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P A R T PRESIDING CI-IAIRMAN W. E. Reynolds Consulting Engineer, N\~ashington, D. C. r 0 u R CosIs and Maintenance MR. SILLING: In tile past, whenever ~ met your next session chairn~an, he did the presiding and ~ was listening, and very carefully. You see, he was in a position to snake one rich. TIe was the Fecleral Con~issioner of Public BuilcTings and hired architects by tile hundrecI. They had to certify their record on a government form in a cJefinite, prescribed manner. There was no place to show those beautiful red, white and blue pipe drunks that architects are very fond of drawing to mislead their clients, and he wouIcl not listen to any fancy talk. A 1larcl ~nan--but fair. And with a sharp knowlecige of how to use an architect eRectively, and also Low much or LOW little to pay hint. Even uncler other personnel, tile clepart~nent that Ile Ileaclec! up still persists in that manner. He was educatec] as an engineer. However, architects have long since forgiven hint for this oversight. TVe are proud to count hint an honorary November of the American Institute of Architects and publicly declare our sincere af ection for fling. Gentlemen, Mr. TV. E. Reynolds, Consulting Engineer of Washington, D. C. 95
. ~ . I: . ~ In-The-Wall Costs MR. REYNOLDS: ~ think that this particular session is one of the more important ones that you have at this meeting. It is very often over- Zooked by many people in the construction industry that maintenance is a very vital factor in the design of ~ structure. We have proved in various ways that it is sometimes profitable to pay more in first construction in order to eliminate maintenance, which is a continuing problem throughout the life of a betiding. Tt is now my pleasure to introduce Mr. H. T. · . ~ H. Ta Nones Turner Construction Company, New York, N. Y. Noyes, Assistant Chief Engineer of Turner Construction Company since 1926. He was chief buiZ3ing engineer and later chief engi- neer of the joint venture titled "Contractor, Pacific Naval Air Bases" at Pearl Harbor from October 1939 through July 1945. He attended the School of Technology of the City College of New York and has ~ Bach- eZor of Science degree and a Civil Engineering degree. He is a member of the American Society of Civil Engineers. MANY great advances have been made in out of all comparison with general living costs. buildings since the end of World War 1:~. While the walls of buildings have increased These advances in design have greatly in- in cost in step with other items. their crocor- creased the usefulness of buildings and certain- ly the comfort and efficiency of their occu- pants. But they have increased building costs --- r--r-- tion of the total building cost has generally gone downward. This is particularly true of masonry-waIled buildings, as is well illustrated 97
by a comparison between a 20-story office building built in 1977 and a sin~ilar 25-story buiTcTing built in 1949-50. The brick and stone walls, including the windows, glass, etc., an~ountec! to 19.~:O of the total cost of the 192/ building. The similar walls of the 1949- 50 building an~ountecT to only S.29~/o. The rea- son for this, of course, is the very great in- crease in the cost of mechanical work in the average building due to the adclition of air conditioning and to a very great increase in the complexity of the electrical system in the newer buiTcling. The cost ratio of the con~- binecI electrical ancl mechanical items in the builclings ~nentionecl above increased front 77.527~ in tee case of the 1977 buiTcling to 44-547 in the 1949-50 building. Tile opinions of the great mass of people who fool; at, visit, ancT occupy buiTclings are greatly influenced by outward appearances. Because of this, the walls have retained and shouicT retain very great importance in the de- velop~nent of any building clesign. Architects in endeavoring to obtain new and modern ap- pearances are designing walls using masonry in its various forms, combinations of masonry; with metal and glass, and combinations of natal, glass and/or other materials without the use of n~asonr~;. While this conference is primarily intenclecT as a discussion of masonry, no such discussions have any meaning without a comparison of the cost of masonry walls with other types. The preparation of comparisons of costs of walls is not easy, as any such comparison nudist recognize that the costs divicle themselves into two basic categories: 1. Direct Costs including flee cost of: a. Masonry b. Metal Savory c. Spandrels d. Windows e. Dampproofing and Insulation f. Scaffolding as i,. Air Conditioning Unit Enclosures 1~. Little and Plaster i. Sun Control Installation. such as Venetian Blinds i. Other similar items a. Indirect Costs . Effect upon Structural Uranic and lTounda- tions b. Efl ect upon I-Icating and Air Conclitioning So stems c. Effect upon Lighting System d. Effect upon Speed of Erection e. Effect upon Rentable Arca f. Eficct upon Window N\:asl~in<, Equipmcut g. Effect upon Sound Transmission 1~. Effect upon Gcncral Comfort of Occupants i. Effect upon Maintenance i. Influcncccl by Code Rcquircments 1;. Inflnenccd by l~irc Insurance Requirements 1. Influenced by Owner s Special Rcquiremcnts, such as blast resistance design. as frcqucutly acquired be; else Telephone Company-. DIRECT COSTS Tile "Direct Costs" are the in place' costs of the various materials which go to make up the buiTcTing wall. These are usually- shown in cletaiT on the arcllitect's drawings and can be rea(lilv; csti~natecl by a general contractor with the help of Isis various subcontractors. Exterior walls may be built in ain~ost an infinite number of contaminations as designers strive for in~proven~ents in appearance, utility ancT cost. Each designer approaches the prob- le~n (lifferently, and as a result sextons are two builclings built front exactly the sense con~bina- tions of materials anc] details. For comparison of wall costs we 1lave ana- lyze(1 the costs of some buildings of which we 1lave knowle(lge and have corrected them for Turner Construction Company s Cost Inclex of July 1956. Before presenting these, ~ thought teat it piglet be interesting to give you a percentage breaLclown of tile various major items in a building which we built in blew Yorl: in 1L949- 50. To(la~7's buiI(ling average is about the same.
Excavation and Foundations ......... Steel France and Fireproofing ........ Brick and Stone 2\I~.sonr~, Windows and Glazing ....................... Roofing and Flashing .............. Waterproofing ................... Interior Partitions ................ N/Ietal Lath and Plaster ............ Carpcntrv and :Millworl: ........... Miscellaneous and Ornamental Metal. Cement Finisl~ Floors ........... Tile Terrazzo and N~Iarble ....... Floor Coverings ................ Painting and Decorating ............ Acoustical Treatment .............. Finished Hardu arc ................ Security Vaults ................... Heating. Ventilating and Air Con ditionin~, ............. Plumbing .............. Spiring and Fi:;turcs ..... Elevators and Con~cvors ........... Job Supcr;-ision and General Expense. 4.53~o 16.92 . 8.l: . 0.45 . 0.36 . 8.29 . 7.37 . 1..26 . 2.~ .. 1.~S ~ ~ - .. /.~) .. 0.57 0.69 :.45 0.2/ . 0.60 . . 19.55 .. 5.59 . .10.2S . 9.12 . 1.40 1 00.00 Yo In preparing the following cost comparisons, we lease. unless otherwise noted, considered only; the following items: a. 2\/Iasonrx b. Metal NVorl; c. Spandrels d. Windows e. Dampproofin~, and Insulation f. Scaffolding \Ve leave not inclucled such "Direct Cost" items as Air Conditioning Unit Enclosures, In- terior Furring and Finishes, Sun Control and similar iten~s. These are not a feature of tl~e exterior wall as being considered here, as the similar designs of each could be usecT with any type of wall. Further, their costs would not seriously alter our present comparisons. Tonne comments will be made later regarding then. Tile following is a condensecl listing of a number of unit prices for various buildings with different walls. The chart below shows the n~ake-up of each of these walls in snore detail. :Et must be recognized that these are only approximate prices to be used very care- fully. Minor changes in location or condi- tion Night result in appreciably different prices. UNIT PRICES FOR VARIOUS BUILDINGS Type Location Description Price/sf. 1. 32-stor~ ofEcc NO Yorl: City Face Brick and Aluminum Sash . .. $ 5.20 2. '-4 story; lab. New York State Roman Brick and Aluminum Sash . . . 5.47 3. 5-stor; l~ospital New York City Brick Caxity \Vall ...... ........ 4.60 4. 25-stor~ office New Yorl: City Limcstonc- Alum. sash and spandrel . . . 7.40 4a. 25-stor~ office New York City Limestone includ. spandrel Steel windows ... . . . 6.1 5 5. 6-stor; Telephone Near New York City Blast Resistant limestone and cone .... 8.90 6. 2-storx lab. New Yorl; State Alum. Porcelain Enamel and glass 6.30 7. 41-stor~ ofI;ce Pennsylvania Limestone with stainless steel windows and Steel spandrels 12.30 8.42-stor~ office New York City Stainless Steel with reversible sash 7.20 9. '-story office New England Alum. Stainless Steel Trim and 3/s-inch Solex Glass . . ............... 11. / 5 10. 2-stor~ office Near Philadelphia Porcelain Enamel Stainless Steel and Glass 11.60 11. 1-stor; manfg. Virginia Concrete tilt-up and corrugated asbestos. . 1.22 99
All of the above prices are per square foot costs. In addition to the above we have estimated the cost of several other types of masonry faced walls: I. Marble faced exterior walls using ~s-inch marble facing and 8-inch common brick should cost between $7.00 and $~.50 per square foot provided a normal domestic marble is used. 2. Granite faced exterior walls using /-inch thick granite and 8-inch common brick back- ing should cost about $12.00 per square foot. 3. Mosaic faced exterior wall in the form of a precast 8-inch Waylite panel of maximum size-5 feet x 10 feet facet! with Casavan mosaic would cost from $5.00 to $6.00 per square foot installed. This panel has a 4-hour fire rating and Toacl carrying capacity of about equal to a ~ 7-inch masonry wall. These prices are for the area of the mason and do not include windows, glass, insulation, etc. INDIRECT COSTS To discuss "Tndirect Costs" in any detail would require far more time than is available Heat Loss through "Window" NVall: Glass 70 sq. ft. Insulated Wall 30 sq. ft. here. However, we believe that a few general observations might be well worth while. T. Structural Frame and Foundations For years Engineers and Architects have con- sidered the effect of the weight of walls on the design of the structural frame and the founda- tions. Little more need be said about this ex- cept that the influence of the weight of the wall is far more important in tall buildings than in low ones and that Pile or other expen- sive forms of foundations are more influenced by weight than are rock or high bearing value soil footings. This problem lends itself to rel- atively easy analysis. 2. Heating ant] Air Conditioning The effect of the exterior wall of a building upon the size and design of the heating and air conditioning system is very important eco- nomically and nest be considered by the Me- chanical Engineer in designing the system. In studying this effect, we took two building walls each 8 feet Tong by 12 feet 6 inches high. In one building we assumed a "Conventional" wall of masonry and 30~0 glass area. In the other we assenter! a "Window" wall of metal and panel construction and 70~0 glass area. HEAT LOSS CALCULATION 100 BTU/hr. 7000 BTU/l~r. 6 BTU/hr. 180 BTU/hr. Heat Loss through "Conventional" Wall: (Masonry portion is 12-inch brick with 2-inch furring of metal lath and plaster) Glass 30 sq. ft. 100 BTU/hr. 3000 BTU/hr. Insulated NVall 70 sq. ft. 6 BTU/hr. 420 BTU/hr. Excess heat loss through "Window" Wall One ton of refrigeration equals 12,000 BTU/hr. Then the added AC load due to "Window" Wall is: 3760 . 12,000 0.3 tons per 100 sq. ft. of wall area 100 7180 BTU/hr. 3420 BTU/l~r. 3760 BTU/l~r.
Our calculations apply to the eastern and western walls of a building. They apply to a lesser degree to the southern wall and still less to the northern wall. The first cost of the heating and air condi- tioning system for a large building varies be- tween $800 and $1,200 per ton of refrigeration. Tf we assignee that variations in wall type would merely alter the size of the system to a degree and that the price per ton for the added re- frigeration would be only 507 of the above prices, the increased cost of the heating and air conditioning system in the "window" walled building will run from $~.20 to $~.80 per square foot of wall more than the "con- ventional" walled building. As noted, these figures apply fully only to the eastern and western walls. Tf these walls total 30,000 square feet, the increased cost of the heating and air conditioning system would be $36,000 to $54,000. In addition the operating costs go up proportionately. For a "rule of thumb" we may say that an additional ton of refrigeration is required for each 130 square feet of 12-inch brick wall with metal lath and plaster furring which is changed to glass. This means that if the acided refrigera- tion cost $500 per ton, this change costs about $4 per square foot of increased glass area. This applies only to the eastern and western walls. All of the above figures will vary somewhat with details, climate, exposure, etc., but still they indicate how carefully this factor must be considered when deciding upon a wall design. 3. Lighting Tile lighting system of a building must be designed for the worst condition, which of course is night tinge operation. An increased window area does not alter the system. Our observation indicates that in most offices and factories the lights are turned on fully in the morning and turned off by the cleaning force after they complete the evening cleanup. Thus, in practice, no operating savings are obtained. 4. Speed of Erection It would appear that any kind of panel system would result in greater speed of erection than is possible with the conventional type of masonry construction. We all are familiar with the spectacular speed of the erection of the outside skin of several aluminum buildings in New York City an(1 elsewhere. However, it should be kept in mind that the speedy installation of the exterior skin is only one phase of the construction of the wall. In New York where masonry backing is required, it is fount] that the overall spee(1 of erection of panel walls is not very much greater than the spee(1 of erection of masonry walls. There might be some advantage during winter weather when a rapid enclosure for winter protection will save some money. It is cliff;cult to assign a (lolIar value to this item. 5. RentahZe Area Tf the outside lines of a building are fixed by property lines or code requirements, such as is usually the case in a large city, the thickness of the exterior wall is of economic importance. The American Standards Association in con- junction with the National Association of Building Owners anc! Managers has estab- lished that the "Net Rentable Area" of a building space shall be measured to the inside finish of the permanent outer building walls, but no deduction shall be macle for columns and projections necessary to the building. In the case of a New York City building of an individual floor area of 26,000 square feet gross and 19,000 square feet rentable area and a story height of 12 feet, the wall surface per story was found to be approximately 10,000 square feet. A decrease in the thickness of 101
wall by 2 inches wouIcl Lave acicTecI Ti0 square feet of rentable floor area per floor. At a rental of $6.00 per square foot, the yearly income frown this wouicl have been roughiv SS40. Taxis suns capitalizec! at 10~,' amounts to $S,400 or a savings of S4( per square foot of wall surface. In considering this matter of wall thickness, it must be recognized that frequently too snuck effort is Inane to recluce wall thickness widen it is not necessary or even clesirable. An example is in a large builcling built where no property; line or cocle rcquirc~nents governed the size of tile buiTcTing. The wall thickness Was clesignecT clown so much that snore money was spent clue to close tolerances titan if an acIditional inch were acicTec3. mass has the advantage over any; type of light sandwich wall or metal skin with light weight backing. All types of walls neecI maintenance, some snore than others. Those requiring cleaning, calking anc! painting or otiose regular atten- tion shouIcT be analyzecT to cleter~nine the en~- pl1asis to be given maintenance when co1npar- irlg wall costs. TIlis is a very complicated anc] controversial subject. NVe clo not have any generaliv acccptec! information regarding the cost of such maintenance programs. 9. Code Require~ne~zts 6. Window Washing Equitnze~t Whenever consideration is given to cletaiTing tile walls of a building with fixed glass, proper evaluation nest be given to the method of cleaning the windows. In some large buiicI- ings built recently, machines have been built to ride rails on the roof ancT drop some form of car over tile side for the use of tile winclow cleaner. In some instances this equipment leas cost over $100,000. In a number of builclings built since the war, reversible sash have been user] so that the win- dow cleaner can stand in the building ancT wash both sides of tile glass by reversing the sash. :In one such building it was estin~atecT that the cost of snaking these sash reversible rather than fixec] was about $7 ~ 5,000. In this building window washing machines wouIc: have I~a(l to be placecl on several levels due to set-backs, so that close analysis was necessary,. S_ ~ ~ . . /. OU17G 1 ransn~zsslon The transmission of sound through an exterior wall may be of great importance in some Toca- tions. Since sound is stopped principally by mass, the masonry wall clue to its weight and 102 City or state buiTcling cocles frequently; have requirements which greatly; affect wall costs ancT must be given full consideration. Often they require a specific fire rating and so~ne- ti~nes give actual masonry thicknesses and material requirements. Wind pressure design also is important. No generalization of costs is possible here. The foregoing is intende(l to indicate that many factors must be consiclere<1 before select- ing a wall type. Songs of these are: a. Aesthetics b. Publicity c. Use of the Building d. Effect upon Strr~ct~re, :Foundations, and 2\/Ie- cl~anical Installation e. Economics Any of these considerations may be estab- lishecT by the owner as being of top in~por- tancc. I\To one type of wall is best for all pur- poses or situations. One owner may select a wall which is tile cheapest, another owner one which is outstanding in being clifferent of modern, and still another owner must have one which fits into an existing pattern. Only thorough study will give him the assurance that Ile has best gained Isis desires.
Maintenance of Industrial Buildings 1MR. REYN-OLDS: Our next speaker is Mr. MyEre of - the duPont Company. He is a spect~cations man. He is a designer with struc- turaZ experience. And he is with a great com U~TTIL comparatively recent tinges, penna- nent industrial plant buiTclings were invariably constructed with masonry walls. Stone or brick buiTclings offered ~naximu~n fire resistance and endurance and lent themselves to ~nini~nu~n maintenance costs. Stone wadis were inherently thick-two feet or more. Since labor was cheap, brick walls, too, had a thickness of twelve inches or snore and provided, in acTdi- tion to their function as an enclosure, support for floor sy~sten~s. Thev were ~enernilv solic1 . . . _ j ., ~ A ~ ~ ~ V ~ J ~ J. A CAL brick throughout their thickness. Under those conditions, ~nasonr,v was pretty stable ancT very little cracking and leakage occurred. All M. Myhre E. I. duPont de Nenzours and Company, I7zc. WiZmi7zgton, Del. pony. He is seZf-eclucated anti has been a con- struction superintendent and a designer. Mr. AZf M. 1MyEre is a registered professional engi- neer in Delaware. The last twenty or twenty-five years have seen n~arkecT changes in inclustrial cTesign. In- creased cost of loots labor and material has clictatec] many of these changes; others resultecT front new technological requirements which necessitated more rigid operating conditions. Tile design of masonry wails has been aRectecI along with many other buiTcling components. To accon~plish Tower costs, wall thickness leas been decreased, while the masonry units the~n- seives have increased in size. Greater use of cored units results front an attendant to adjust unit weight so teat masons can 1lancIle larger sizes without increased fatigue again an econ 103
omy~T~ove. Avails havelargely ceased to func- out wheat we can do to correct or eliminate tion as such; they have become enclosures . a skin to cover a structural skeleton. During the period when all these changes were taking place, n~any attempts were negate (and are still continuing) to come up with satisfactory substitutes for masonry wails. To ciate, however, masonry retains its position as the lowest cost, really fire-resistant enclosure for most kinds of industrial buildings. What other type of exterior wall can be constructed for a price as low as $~.50 per square foot ancT be as durable as masonry? Yet, some industrial buildings which conic! appropriate!`; use masonry walls are clesigned with some other type of enclosure. Why? There nest be a gin~nick somewhere in the above statements. Is the quoted cost too Tow? No: the above cost figure has been repeater! time and tinge again on our jobs. Fire resist- ance? That characteristic has never been ques- tioned. Durability? Masonry is the only form of wall construction that has endured through hundreds of years while retaining its original form. Aesthetic quality? Masonry in its various J ~ forms and multitudinous color variations should satisfy the most critical architectural designer. Maintenance requirements? Maybe: that's about the only factor left which could possibly be tagger] with an unsatisfactory answer. Masonry is occasionally subject to criticism. Some of that criticism is justified; most is not. Even though masonry wails occasionally crack and leak, we nest ren~en~ber that there are endless examples of installations which are functioning in a first-cIass manner and will continue to do so for decades. AncI, in spite of the selected accompanying illustrations, du Months experience, T know, parallels that of the industry in this respect. However, our particu- lar subject is "maintenance" so we must, of necessity, point our discussion to the more vulnerable characteristics of masonry and find 104 them. WHY MASONRY WALLS CRACK Plant walls are frequently subjected to forces and strains above and beyond those usually J J encountered in public or commercial build- ings. Temperature variations clue to operating processes may be much wider, affecting both the superstructure and its enclosure. In fact, this factor may loom so large that it is imprac- tical to use anything except a very flexible sys- ten~. Vibration often dictates special treatment. The necessity for locating plants at specific geographical points sometimes introduces un- usual problems in soil stability and climatic changes, both factors in masonry wall stability. The very atmosphere to which buildings are exposed may be contaminating and highly corrosive. Even though masonry is highly re- sistant to the effect of most chemical fumes, cases have been experienced where brick walls have failed completely from internal build-up of sulphate crystals and allied chemicals. Many of the above conditions dictate the use of special (resign techniques. The same procedure may not work in any two similar situations. Consequently, these are special problems requiring special solutions. However, there are two elements that work both sepa- rately and together to destroy the integrity of masonry walls and against which specific pre- ventative measures can be repeatedly effective namely, changes in moisture content and variations in the temperatures to which ma- sonry is exposed. All masonry is subject to moisture absorp- tion to some degree. It is always affected by temperature changes. Peculiarly, moisture and temperature produce exactly the same di~nen- sional changes-an increase in either or both causes expansion, while a decrease causes shrinkage. Not only that, high temperatures are frequently accompanied by heavy precipita
tion so that the effect of both temperature increase and moisture absorption takes place at the same tinge and is cumulative. In addi- tion to these results, dimensional changes in the steel supporting structure resulting front temperature variations exert forces on ma- sonry which create large differential move- ments. The thermal coefficient of steed and concrete, for example, is up to 2~/2 times that of masonry. The forces acting on masonry walls, both front within ancT without, some- times exceed the n~asonry's compressive strength while it tensile strength, as well as the bond strength of mortar, is aIn~ost always ex- ceeded when reactive movements are devel- oped. A wall which is restrained by its support- ing structure or its own mass invariably cracks when shrinkage takes place. When a wall cracks, return to its original position is cut short. During the second and succeeding cycles of temperature and moisture changes, particles of mortar and masonry units drop into the crack to partially fill it so that, at maximum elongation during the next cycle, the position of the wall is somewhat farther along the support than it was at the peak of the previous cycle. Thus the results of cyclic changes are cumulative. Sonnetizes, evidence of cracking is difficult to detect because the change has produced short, thin openings dis- tributed over wide areas, but if a wall leaks, they are always there. Two types of cracking are involved. One is identified by opening of mortar joints at the interfaces of the masonry units resulting in hairline cracks which do not necessarily extend from brick to brick. Such openings form chan- nels for infiltration of water by capillary action. The other kind of crack is recognized (l ~ by its size which varies from hair line width to that big enough to "lay a hand into," and (2) by its direction and course which frequently is directly through brick without regard to the position of joints, or zig-zag from brick to brick and course to course. The first type is caused by shrinkage in indiviclual masonry units, accon~panie(1 by poor adhesion of joint mortar and the use of mortar having high shrinkage characteristics. The second type is caused by shrinkage of whole sections of the walls, together with the results of differential movements restrained by collateral construc- tion. About three years ago our company initi- ated a study to find out why we were getting adverse comn ents on masonry walls front the operating management of some of our plants and to determine the procedures which wouIct eliminate recurrence in our new buildings. Many plants in widely separates] locations were visited. The condition of their masonry walls was closely exan~inecT and the causes for crack- ing analyzed. Let me show you some of what we found. Figure ~ shows one wall of the cafeteria builcling at one of our plants. This builcling as well as all others at this plant has composite walls with brick facings and sn~ooth-faced hol- low tile back-ups in a total thickness of eight inches. Most columns were encased, with the tile or brick in intimate contact with column 105
~:~:~:E:~:E:E:::E~E:::E~E:E.E:E:E:E~E:E~ESE:E.E.E~E~E:E:E:E:E ~ ~::E: FICLRE 2 Aces and H~ngcs. Ecc~usc of thc Icstf~int oE fc~cd by cnc~scmcnt ~t columns, thc ~alb cr~c~cd vcltic~lly ~t c~ch column loc~tion. Abo notc thc opcning of [c~d ioints tbrough out thc ~B ~rc~. Considc:~blc movcmcnt Lc~c b~s Tcsultcd from thc~m~1 ch~ngcs ~nd FICCRE 3 v~ri~tions in moLturc contcnt. Figurc ~ sbo~s ~t h~ppcns on thc insidc of thc ~Hs ~t thcsc loc~tions. ~otc bow tbc column cnc~sc- mcnt b~s shc~rcd ~y from thc ~1L Figurcs ~ ~nd ~ sbo~ mucb indiscdmin~tc cI~cking tbrougbout thc ~E J1CO, p~rticul~rly in thc p~pcts. Ibc columns of thcsc p~rUc- ul~r buildings ~crc not cnc~scd, so thc vcrtic~1 CIOCtS ~t column lincs did not dcvclop. No~- cvcr, bcrc ~s ~cL ~s in Figure I, ~c c~n obsclvc thc rcsuRs of poor tond bct~ccn mort~, ~nd FICDRE S :::::~: FICLRE 4 106 . FIC~RE 6
h. ; .; ~ l - ~ ~ l FIGURE ~ I'rick and of ~nove~rcuts in the masonry wall itself. We leave experienced much trouble with parapet walls. Both surfaces of these building elements are subjected to extremes of moisture infiltration and thern~al changes which cause n~oven~ents differing front those in the wall below which is exposed on one side only. There is generally a through-all flashing ap proxin~ately a foot above roof level which acts to separate the parapet physically front the wall below and locates a plane of weakness. Tllis is true, even though the flashings tl~c~n selves have been designed to promote continu ity of mortar bond. In addition, parapets lacl; the weight necessary to hold masonry units to gether and maintain integrity. Sometimes at te~npts are made to protect the insicle of para pet walls with flashings extending front the roof to the underside of the coping in-orcler to Intuit exposure. This technique often proves in edective. We are just finishing repairs to para pet walls treated in this manner on a Jaboratorv building at one of our plants. Figure 5 shows lion one parapet wall has expanded ant! bowed outward so that its face FIGURE overhangs that of the wall below by 3/~". Fig- ure 6 shows how expansion has distorted anc! displaced the parapets at opposite corners of a building. In this particular case, the wall in- volved was about four hundred feet long and was constructed without expansion joints. Elongation progressed to the point where an overhang of 7~/' inches occurrec! at both cor- ners. Tile forces developed during expansion are terrific. In Figure ~ is illustrated the sill of a floor used for loading and unloading purposes, located at the seconc! floor level. The right hancT jangle of the frame is positioned close to a four inch jog in the wall, wills the column at that point completely encased in n~asonr,v. The restraint offered by this combination of details was suflicient to cause the brick in the facing to spell at the sill location as it expan(led to 107
ward the corner. The jamb of the frame offered less restraint and bowed. The wall below the sill buckled while a wide crack cleveloped as the forces sheared the n~asonr~; at the internal corner of the setback. Figure ~ shows another example of results of shearing stresses as a wall about 700 ft. long expanclec! into a setback. When concrete foundation walls are ex- posecl to a height of nave than a foot or so above grade, thermal changes cause cracking in the foundations. The stresses attendant to that phenomenon are transferred to the ~na- sonry above, and it also cracks. Frequently such fractures are erroneously defined as settlement cracks. ~ hey are not. Settlement cracks can be identified by their position ancT by the fact that they are wider at the top or Cottons de- pending upon their location in the foundation. These cracks are of uniform width throughout the exposed foundation height. Figure 9 is a typical illustration of this type of failure. The illustrated masonry crack starts at the bottom of the masonry walls on top of the foundation FIGURE TO FIGURE 9 108 ~ ~ ~ ~ ~ ~.~ ~.~ ~.~ ~.~ ~.~ ~ ~.~.~.~ ~.~ ~ ~ Ace. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ FIGURE 12
FIGURE 13 and disappears at a point about 3 feet above. Figure 10 shows the ~nagnitucle of the forces involved: even a 6" thick precast concrete panel was affected by such a founciation crack. One of the obscure reasons for masonry failures is illustrated in Figures ~ ~ anct ~ 7. In the first, the walls support a senate section of concrete roof slab, poured in intimate con- tact witty the top of the wall. Upon setting and curing, tile stab warped, causing ruptures in tee masonry at tile corners. A similar concli- tion cleveloped under poured in place concrete window sills as shown in Figure 17. Another tripe of failure which can be serious is the one shown in Figure 13. We fistic! this happens in most cases where wall-bearing (le- sign is usecT. Cracks develop at the intersection ~C~ . ~. . Of partitions witty exterior walls along both sides of the building. They are wicler at the top than at the bottom; in fact, frequently disap- pear a couple of feet above the floor line. Gen- erally, the roof fleck is of poured concrete- either a thick structural stab or a thin stab over bar joists. However, in one case the sense thing happened where a metal deck was inacI- vertently extencled into the wall. High summer temperatures cause expansion of tee cleck. and the n~oven~ent pushes the loacI-bearing walls outward at the top. This condition has been observed to progress to the extent that horizontal cracks have appeared in joints Tocatecl at tops or bottoms of winclows. The extremes to which maintenance work roust be carried if we fait to recognize design fundamentals are shown in Figures 14 anti 15. The wall in this case was rigicITy anchored at one end by an intersecting builcling unit anc! FIGURE 14 109
FIGURE 1 5 all expansion progresses! toward the free corner. The columns were all partially encased. Total n~oven~ent over a period of 10 years was about 3 inches and wall stability was affected. The walls cracked vertically at each column location while the encasement sheared front the inside face of the walls. Figure 14 shows reconstruction work at the corner done about 3 years ago. Note that freeing the walls front the columns and providing an expansion joint has stopped further carnage. The expansion joint shown in Figure 15 extends from the bottom of the coping to the top of the support- ing spancirel. Tile cover plate serves only the purpose of preserving the resiliency of the call:- ing con~pouncI. Use of the better types of n~a- terials now on the market will eliminate the necessity for the cover, if tile joint is not ex- cessivel~; wicle. MAINTENANCE COSTS AND PROCEDURES NVhen we talk about maintenance work of any kincI, the terns implies that renewals or generalities. 110 r epairs of a repetitive nature are involved- that something is necessary to restore or main- tain original integrity, that deterioration is anticipated, and results for natural wear and tear. Can we apply that definition to mainte- nance of masonry walls? In a broad sense, yes. However, masonry walls neec! maintenance work only if they crack, if they or their con~- ponents disintegrate or if they leak. To repair cracks and stop mortar disintegration, repoint- ing is necessary; to obtain adclitional imperme- ability to moisture absorption or transmission, waterproofing may be necessary. However, re- pointing is not done on an annual or biennial basis: it is sel(lom repeated during an ensuing quarter century-. Only in extreme cases is it necessary to rebuiTc! whole wall sections to re- store structural stability if expansion has caused extensive damage. But even if such a repair is required, it is seldon, repeated dur- ing the entire remaining life of a building. The only phase of masonry maintenance that can be properly defined as such, is that of water- proofing by the application of some type of coating to exterior wall surfaces and of replac- ing calking around the perimeter of openings. Since the advent of silicone coatings, masonry walls are frequently waterproofed in~n~ediately after completion with the recon~n~endation that the coating be renewed periodically. The preceding partially explains why it is so clifEcult to cone up with factual data on ~nain- tenance costs. Plant records in many instances are not available to establish costs of repairs which may have been completed 10, If, 75, or 50 years ago. Also, because of the nature of the failures involved, repetitive yearner appropria- tions for masonry repairs are not made in the same manner as allocations for equipment maintenance, painting, electrical work, etc. Yearly approprations for masonry repairs are based on specific requirements, seldom on
How many of you leave ever seen clolIars and cents evaluations of masonry maintenance costs? Not many! True. there are unit prices for cutting out masonry joints ant! repainting, for possibly replacing a section of masonry Alicia failecI structurally for some reason or another, for recalling where necessary, or for application of waterproofing compounds. But where have you seen any figures setting forth the cost per year for maintaining n~asonry walls of, say, $1,000,000 worth of buildings? During the course of our masonry wall study we nude concerted efforts to evaluate costs of maintaining masonry walls. We canoe up with answers on specific items of repair of recent execution, but data could not be in- tegrated into over-all costs. For example, one of our largest plants, manufacturing heavy chemicals, is composed of buildings up to 50 years of age or snore. The masonry walls of its buildings vary greatly as to the kind of n~a- sonry units used. Some enclosures have leaked, necessitating some maintenance work but, in general, all walls were performing satisfac- torilv;. An estimate of over-all maintenance costs was impossible ancT in~practical. At another plant, where materials are con~- pounded for sale to plastics manufacturers, much trouble was experienced with leaLv J walls. Almost all of the original buildings on the site were involves! and upwards of $30,- 000 was spent, over a period of four or five ~:ears, to make necessary repairs. However, perfonnance during the last three years has been good and with an occasional application of waterproofing liquicls it is anticipated that a satisfactory: status quo can be maintained. The costs here cannot appropriately be ground into a formula which will give over-all results. In 1943-50, one of our large textile plants was constructed in South Carolina. Its walls were constructed of a single wythe of jumbo brick and were ~ inches thick. Performance to date has been satisfactory and little mainte nance work has been required. However, in 1950-57 another similar plant was built in North Carolina and here trouble has been encountered. It was particularly unfortunate for this plant to have been subjected! to the heavy wind-driven rains of three successive hurricanes. Eight-inch thick walls constructed of one wythe of hollow masonry units such as jumbo brick are harclly proof against this kinc! of exposure as you can well guess, but an investigation exposed several faulty details which were the main sources of trouble. Re- pairs included some cutting out and repoint- ing of joints and cracks, an over-all application of silicone waterproofer and some flashing re- pairs. Costs of repairs on this $60,000,000 plant have amounted to approxin~ately $20,000 and the need for repetition during the next 5 to 10 years is not anticipated. If masonry walls have cracked, the most edective repair procedure used to restore and maintain integrity consists of ~ ~ ~ providing flexible fastenings to the supports, (7 ~ remov- ing restraints wherever they exist ant} (3) to cut in expansion joints at strategic locations. Flexible fastenings will permit freedom of noven~ent without restraint, while expansion joints will prevent cumulative elongation. It is very necessary to provide tight seals at joints in copings (when parapet walls cannot be re- moved) and at the perimeter of all openings, sleeves, etc. Use of calking materials, such as the new synthetic elastomeric confounds, which retain elasticity indefinitely rather than the use of oil-base materials which cIry out and become brittle in two or three years, is a necessity. Waterproofing with silicone water- proofers is a good way of sealing the surface. However, this material cannot be expected to seal openings against wind-cTriven rain, other than those of inherent porosity or hair-line cycles. Wllen the faults of any product are dis- cussecl, it is necessary for full comprehension 111
to bring all of its acIverse properties into the open. This has been done in the case of ma- sonry walls. However, the over-all picture is by no means as bad as discussion of inclividual examples seems to indicate. We have built millions of square feet of masonry walls which are functioning satisfactorily. CONCLUSIONS NVe are' in masonry construction, dealing with very durable, but also very rigid and in- flexible materials. The way in which these materials must be used today diFers front that which determined design criteria in the past. Let us start thinking in terns of masonry en- closures, or skins, instead of walls. As Tong as masonry enclosures must form skins for steed or concrete superstructures, let us treat then as skins. If we accept this viewpoint, recognize the limitations of our materials and design accordingly, we shall have much less trouble. There are some very basic physical laws gov- erning the performance of masonry materials which must be respected exactly the saIne as for steed and concrete or any other building elen~ent which is not purely decorative. We can term observance of those laws, ant! their application to design of new structures, a form of preventive maintenance. Some rules which must be followed are these: 112 or floor stabs ant! the inside face of ~nasonrv walls. 3. When spandrels are necessary for support of masonry in n~ulti-story buildings, negate then stiff even to the point of preventing deflection of more than T/500 of the span and provide slotted connections at one end to prevent cun~ulative expansion. 4 Provide expansion joints where necessary. They shouIc! always be positioned so as to separate building segments or wings and should be strategically located at other points throughout the wall. We have found teat the provision of one expansion joint in each 140 ft. of straight wall is quite satisfactory when walls are faced with burned brick units. 5. Eliminate parapet walls. The advent of prefabricated metal facias introduces an excel- lent n~ediu~n for finishing off the tops of walls and edges of roofs. 6. Use calking compounds which rennin truly elastic and provi(le lasting adhesion to both masonry and metal surfaces. Such n~a- terials, although higher in cost than conven- tional calking, can be applied at no greater cost than the latter so that the over-all cost is not excessive. A greatly extended, trouble-free life span makes then very economical, incieecI. 7. It is always advantageous to waterproof masonry walls as soon after completion as I. Recognize that walls undergo clin~ensional practical. changes and that restraint cannot stop n~ove- ~nent. Provide wall stability by using flexible ties to columns, beans anc! spandrels. Wire or strap ties arranged so as to slide behinc! a bar welclec3 to colognes or beaten flanges pro- vicle satisfactory; fastening. 7. Except when absolutely necessary, do not surround steel or concrete columns, beans or spandrels with masonry. Especially, do not place n~asonr,v in contact with colun~ns. Pre- vent physical! contact between edges of decks S. Keep the Alkalis ciry as they are constructed. This is very important. Do not wet brick un- less their absorption rate is very high or un- less the weather is very loot. Uncler no circurn- stances wet concrete blocks used for back-up or allow then to get wet in storage. Protect the portion of walls laid up in any work perioc] against bandage front the elements. 9. Tailor the mortar to be used to the type and the characteristics of the masonry units selected. When the moisture absorption rate
is Tow, use mortars with higher proportions of Portland cement to achieve maximum bond strength. When absorption rates are high, in- creasing the Tinge content will prove helpful by providing greater extensibility and water re- tentivity and promoting better boncI. after tooling. If setting has progresses! too far the mortar cannot be adequately densified. In conclusion, let me state that, since we in our organization started to engineer our masonry walls OI1 the above basis, greatly in- creased water tightness has been achieved ancl structural cracking has been virtually; elin~i 10. Do a good job of tooling. This means, Hated. We can unequivocalIv state that n~a essentially, that tooling nest be done at the sorb walls clo constitute very satisfactory en J J ~ right tinge. Mortar which has not set sum- closures forindustrialbuiTclings when correctly ciently will shrink away front brick surfaces engineered ancT constructed. 113
Maintenance of Public Buildings M R . R E Y A- O ~ D S.: ~ 30 not believe there is a anon in America who knows more about the operation of buildings than the next speaker, lA1r. Charles A. Peters. He is the Di- rector of the BuiZ~ings Management Division, PubZic BuiZ1ings Service, General Service Ad- n~inistratio~z of the United States Govern nzent. Mr. Peters has been e~ntZoyed by the PubZic BuiZ3ings Service and its predecessors since his service with the Bureau of Yards and Docks, United States Navy, during Worm War T. He is a Bachelor of Civil Engineering from the University of Michigan and ~ newer of the Charles A. Peters Public Buildings Service General Services Administration:, Washington, D. C. An~erica~z Society of Civil Engineers, the Society of American Military Engineers, the Illuminating Engineering Society, several code committees of the American Standards As- sociation and the International Municipal Signal Association. He is also ~ member of the Washington Building Congress, the Building Owners and Managers Association, Washington Society of Engineers, BuiZ1ings Management Associa- tion, Government Services, Inc., Federal Safe ty Council, Federal Fire Council, The Wash- ington and MaryZan<] Societies for the Blind, and the P.B.S. Welfare Service, Arc. ~ His paper is a report of experience asso- are basic in tile design and construction of ciated with 36 years of living with the prob- public buildings. Tents of builcling <design, buiTcling construction, It would be highly desirable if we could ancT building operation. It represents an effort cluplicate the forces of nature and in a matter to record the performance of materials that of days of testing predict the performance of 115
n~aterials that the architect and engineer will use in erecting their structures. From my ex- perience. ~ believe we are still limited in our conclusions drawn from tests, ant! that time and nature's forces still produce the conclu- sions that are universally accepted. Having been asked to participate in the Conference on Modern Masonry, T have ap- proached the subject from the viewpoint of consenting on the n~aterials that are used in public buildings to enclose the buildings and to partition the buildings. The maintenance engineer, probably snore so than the architect, becomes conscious of operating costs. He can evaluate mistakes in design practices and quickly observe the cle- fects in workmanship and those resulting from poor inspection. He navy take the tinge to pass back to the buiTcling designer and the pro- ducer of materials, corrective suggestions or information that would alert them to errors in design or in manufacture. The usual course, however, scene to be to live with the mistakes and to attempt corrective alterations and re- pairs. \Ve do review our design practices, such as design details and specifications, periodically. Recently a committee of seven experts was ap- pointed to study and report on the documents, criteria, and practices that establish design and construction standards of public build- ings. Their objective was to bring the existing standards in line with good con~n~ercial prac- tice consistent with Federal requirements and to insure n~inin~un~ operational and n~ainte- nance costs. it may be of interest to repeat a sentence front the con~nittee report that relates directly to the subject. The contingent concerns exterior facings. "Public Buildings Service should not experiment with any particular type of con- struction but shouIcT use proven materials to assure n~inin~un~ operational and maintenance costs." 116 EXTERIOR WALLS- DESIGN AND CONSTRUCTION When selecting the materials for exterior walls one thinks in terns of durability, ap- pearance, weather-tightness, unit cost of n~a- terial in place, and Tow maintenance cost. There are other factors that are important to the architect, possibIv classed loosely as the aesthetic requirements, but to those respon- sible for maintenance and operation, n~ate- rials requiring minimum maintenance are ideal. Granite brings to mind a material that is ageless. It is used today by the architect for a partial treatment of the exterior of a buiTc3- ing. It has some disadvantages in today's con- cept of a public buiTcling, and these are Eight and first cost. On the other hancI' tile build- ings we operate that are granite faced are practically free of maintenance costs for stone work. I.inlestone is the most widely used stone for exterior treatment and when selectee} for qualities of hardness, surface texture, and re- sistance to moisture, is on a par with the other materials for beauty in design and Tow n~ain- tenance cost. It is one of the outstanding stone materials for a public building. Marble as an exterior treatment is one with which we have had lin~ited experience. There are a few public buildings that are n~arble faced but it is a stone that lencis its beauty to interior finishes. Where extremes in weath- er are not conditions that have to be consicI- ered when selecting exterior stone, marble is an excellent stone with low maintenance cost. Sandstone has been used to some extent for exteriors on such builclings as the White House, the center wing of the Capitol, the Court of CIain~s, and other public structures. it is most successful in this use when kept painted. Brick as one of man's oiclest buiTcling n~a- terials is an excellent treatment for exterior
use. We have notary brick faced) buildings which give excellent service front the stand- point of Tow maintenance cost. This is one material that requires careful inspection clur- ing construction if the buiTcling wails are to remain free of water. The entrance of water has been our principal source of trouble and the most difficult to correct. The cause is us- ually poor workmanship or skimping on the vertical joint mortar. We have exan~ples of this at SuitIand, Maryland. Terra cotta has n~anv qualities to recom- ~nend its use in builclings. Its history, however' as an exterior building n~aterial, records many instances where trouble resulted front design defects, anchor corrosion, failure to consicler climatic changes, and installations that were ctiflicult to reach ant! maintain. As a n~an- ~nade n~aterial, it readily fits into arcLitec- tural concepts and can be so rnoulded. Concrete exterior walls have not been too well received when considered in public build- ing design. In some parts of the country, con- crete builclings for public use have been con- structed which are achitecturally beautiful. In the limited experience we have had from the standpoint of maintenance, this exterior treat- ~nent appears to have Tow maintenance cost. Our niacin difficulty has occurred in designs which did not fully allow for temperature changes and resulting movement in the span- clrels. Our Federal Warehouse, here in Wash- ington, is an example. Stainless steel as an external facing mate- rial has not been one of our problems. It is too new and wit] have to prove itself as a pro- tective skin before it has wide acceptance with architects of public buildings. Glass in the form of panels or blocks is not a n~aterial that has been used to any extent for the exterior treatment of public buildings. EXTERIOR WALLS MAINTENANCE Maintenance problems that have concerned us in connection with exterior stonework have been widespread geographically. They result ,fron~ climatic changes, design weaknesses, poor workmanship, and inadequate inspection. The materials used for setting ant! pointing have also player! a large part in contributing to our problem, and in some instances the corrosion of anchors has produced major fail- ures. Poor inspection can be cleaned in a nun~- ber of ways, but our experience indicates its cause stems from too much reliance on the workman to conform to design details that are not fully understood, limiter! funds to hire qualified inspection personnel, and leniency on the part of the men responsible for getting what was intended. Specifications should include the require- n~ents that will adequately describe the n~a- terial and assure rejection of faulty pieces. Material inspection is very important if we are to obtain the quality material specified. Considering stonework from the viewpoin of installation we fins! that poor workn~an- ship, unsatisfactory bonding materials, and lack of protection of the work during con- struction are the principal sources of trouble. The tendency to use high-strength mortar usually results in poor bone! with the masonry units. Shrinkage quite often destroys the bond between the masonry units. Mortar design or formulation has been widely investigated but it still remains the weak point of a n~asonry-faced structure. Pos- sibly because it is relatively simple to prepare' it remains a point of weakness. Much can and has been written on the subject, still it is the principal cause of the need for periodic maintenance of stone work. Much greater success has been attained with brickwork than with stonework from the standpoint of mortar design. Here the chief trouble has been the difficult task of trying to get sur~cient mortar in the vertical joints. 117
Where pointing mortar is used, there is a tendency for a crack to clevelop between the mortar and tee masonry unit which admits water. Where a rich mortar is useci, tee stone on one sicie of the joint wit} often spell off. These difficulties have lee! to the use of calking compounds in many cases. Calking ~natcriaIs have been ancT still are relatively short liver! in maintaining a perfect seal. View formulations appear frown time to tine, but tee period of effectiveness is quite short when exposed to the sun. Revere calking materials are required, teeny shouIcl be usect where in- spection is easy and repairs can be oracle with- out too much clil~culty. Design shouIcT be such as to eliminate the pocketing of water when the calking material fails. Waterproofing materials Lave receixiec] carc- fuT consideration when we faced the problem of camp walls or walls that permit the pas- sage of water. Talc materials so ciassifiecl have a relatively short life before requiring acicTi- tional treatment. This is particularly true when exposecl to the sun. T ant of the opinion there is still no silent cut to a weather-tight structure except by the use of souncT materials, skilIfully placecT ancT clesignecI to cTevelop their full capabilities. Metal skins, Allen they Second accepted in tile saline sense as we accept stone-facecT struc- tures, will bring their own problems of ~nain- taining a weather seal. Glass panels anc] blocks oder features that will intrigue tile architect anc! may be usecT more extensively in the future. Whether they wit} solve the problem of maintaining a weather-tigI~t building anc! one which will be economical to maintain and operate, remains to be seen. EXTERIOR PROBLEMS When considering exterior problems we all agree that the parapet wall is our principal of- fender and produces more troubles than any other part of the buiTciing. Since the parapet is 118 more exposed, it is subject to greater expan- sion anc] contraction than any other part of tile building. This probe of expansion, to- gether with flashing difficulties, nouns leaks, water infiltration, freezing, anchorage failure anc! masonry cracking and clisplace~nent. Tl~e solution is only possible through the most careful consideration in the design and construction of the Nan; details involvecl, witl1 verse special emphasis on expansion. We be- lieve tile best solution, where possible, is to omit the parapet ant! our present revised stanciards so provide. An example of this problem occurrec! in tee Seattle Court House where the exterior terra cotta facing of the building has been seriously cian~agecI, water getting in through the para- pet due to inadequate flashing ancT counter- flashing. Tile moisture 1las penetrated tile e:;- terior wall, causing cliscoloration of the terra cotta and leakage on the interior ceilings. Tile probIcn~s that develop tI~rougl1 i~nprop- cr anchorage or failure of anchorage, usually through corrosion, are many ancT their cor- rection is very costly. ~ could sight many ex- angles but the following three in clifferent types of masonry will illustrate the problem. In the Cleveland Post Office the exterior fluted stone pilasters, througl1 improper an- chorage and support, ca1ne loose and some were projecting due to frost action. Since large stones were involved high on the exterior face of the building, a very expensive job of resetting and anchoring resulted. In Dallas, Texas, tl~e brick pier facing bc- tween the 14tl~ and 15th floor levels of a 19- story building fell on the roof of an adjacent 3-story building. It was found that the brick facing was improperly anchored to the struc- tural framework. The cost of rebuilding and settling claims was in excess of $700,000. In Chicago tile three upper stories of the America-Fore Building were faced Title terra cotta. Water entering through tile joints cor
roded the anchors and several large sections fell to the street below. Luckily no one was injured, but the entire three stories of facing hacT to be removed and replaced at a cost of several hundred thousand dollars. If stone walls are to be kept titlist, a planned program of exterior pointing and calking is necessary. Careful inspection is needed to determine how often this must be undertaken. We have not been able to de- velop a formula that would apply since man; factors, including exposure, size of stone, type of joint, kind of stone, and quality of original work, all play a part in the life of pointing and calking. NVe have found that most struc- tures will require some pointing at least every ten years and some calking every three years. Strange as it may seen, we have had to re- pair ciamage caused by lightning. One ex- an~ple is the General Services Building where several hundred dollars in Manage resulted on two occasions front strikes on the parapet wall. Buildings like the Washington Monument ancT the LincoIn Memorial have elaborate lightning rod systems properIv grounded to prevent Bandage. Time will not permit any covering many other problen~s, such as that introcluced by birds roosting on buildings, lent they are many anct varied. INTERIOR WALLS- CONSTRUCTION Interior construction problems that occur frown occupancy changes are usually the result of organization changes in the tenant agency. The clay is gone when the architect can Cornily plan on how the interior space of a public builcling will function. Verb often before the contractor has completed his work, changes are called for that are costly. Why, you may ask, is this permitted? The reasons for the changes are usually sound and functionally ciesirable. Recognizing this situation, it is nec- essarv to plan carefuliv the use of interior J ~ partition materials. Since weather is no longer a problem with interior walls, the bonding materials are not too critical. Maintenance is minor, and the more costly materials can be justified on the basis of permanency in many locations. When repairs are necessary;, the cause is abuse or faulty workmanship. Materials such as marble, limestone and brick can be used in constructing main corri- dors, elevator lobbies, service and mechani- cal areas. Our experience indicates that marble has decided advantages in lobbies and main corridors. Marble is very attractive for such use, re- quires very little maintenance, is easily cleanest, and will stanct reasonably hard service. Wllv people abuse interior walls by placing their feet against then, writing on then, or other- wise defacing tureen is hard to understand, but they do, and marble surfaces will take that abuse without serious damage. Granite can be used where Bandage is quite probable or service may be very severe. Glass block and glass panels are clesirable in songs locations because of low maintenance and cleanability. The sense is true of terra cotta for floor surfaces and for decorative treatment in corridors, lobbies, auditorinn~s, and public areas. INTERIOR PROBLEMS Speaking of tile floor surfaces ren~in(ls nice that the design and construction cletails must be planned to insure low maintenance and operating cost. An example of the wrong solu- tion exists in the Interior Building, here in Washington. The joints between the floor tile are about 3/8 of an inch wide and were slightly depressed to allow for any irregularities in the surface of tile. Tile result was a very attractive floor but. when we began to clean the floor with a power scrubbing machine, we found a serious defect. The machine which uses a squeegee to remove the water would not pick up flee water front 119
the joints. This resulted in the use of a see- the tenant should be satisfied because the ond Plan to mop behind the machine, thus architect knows best. As an operator, I quickly requiring two men to do the job instead of learned the tenant had ideas of his own. Many one, and doubling the cost. The type of n~aterial to be used for interior partitions dividing the office space into rooms has received a great deal of study frown the operating man in recent years. We have used masonry partitions, metal and wood ceiling- high n~ovable partitions, Tow-height movable partitions. and the dry-wall type of partition. We have sought a low cost solution that would insure n~axin~u~n flexibility. Eve have about concluded that there is no one solution for all buildings and all types of occupanc!. NVe find that each propylene re- quires study. In some types of occupancy, we found that we did not move partitions as often as was expectecI. Some tenants could use the low-type partition witty good results while this type partition completely disrupted the work of other agencies. OPERATOR S VIEWPOINT Front the viewpoint of the manager ancT operator of public buildings it is very i~n- portant to know materials and to observe how they were specified to be used by the architect and engineer. This knowledge can be partic- ularly useful when repairs, alterations, anc! maintenance problems are resolved. To ob- serve weaknesses in clesign details and speci- fied materials is important. Suggested i~n- prove~nents will be particularly helpful to tile design once to prevent tee repeating of ~is- takes. PreviousIv ~ referred briefly to tile special co~n~nittee of experts and their caisson. The operating people worked witty that con~n~ittee when they reviewed specifications and design details and directives, which required chang- ing, to correct faults and improve future de- signs. Too often the architect has the view that 120 in~prove~nents that develop lower operating costs originate frown tenant suggestions or front the operating organization. C OSTS Operating costs of Federal buildings are subjected to careful review by the Bureau of the Budget and by the Congress. The con- tinuing study to arrive at still Tower operating costs challenges the ability of the operator. In searching for tee newels to accomplish this objective without cutting service, the operator must focus his attention on the materials of wl~icl1 the building is constructed as well as on the design of the building itself. Because a Federal building 1las an indeter- ~ninate life, that is, it is not planned and not constructed for a specified number of years' new materials are subjected to searching in- quiry before Ploy can replace materials that are "tine proven." This may be disturbing to some manufacturers but it is necessary. The architects that design Federal buildings are aware of Ellis widen they create their design. It does not mean the absence of progressive construction or ignoring new concepts in cle- sign, but it does mean tl~e use of the building materials that leave withstood the test of time in public buildings. Maintenance costs of specific materials are very difficult to tie down because they clo not occur annually. Fallen failure takes place due to faulty design, poor worl~n~anship, or the presence of materials that should have been rejected, costs that are sizable in amount may occur. Even here, they are so scattered geo- grapl~ically and by years, that the costs are usually not a large part of the operating budget but are certainly an unnecessary part Chicle we would like to eliminate.
Discussion MR. REYNOLDS: The first question is ad- the roof to interior locations or gutters that dressed to Mr. Noyes. it reads '`$1.72 for would be of ample size. :Et is usually done by tilt-up wall. Does this include sash and equip- sloping the roof to interior downspouts. went, surcharge for lifting?" MR. NOYES: It does. It includes the tiTt- up section it includes the corrugated asbestos, which was used as dividers between windows and above the windows, and it includes the sash itself and the glass. It was a complete wall for that purpose. There was no interior finish, there was no fanciness to that wall. It was a straight industrial wall. MR. REYNOLDS: The next question is to Mr. Mybre. What is the relative importance of moisture and temperature movement? What is the order of magnitude of moisture expansion in brick walls? MR. MYHRE: Well, that is a little difficult to answer. It seems that there are no ciata that T have ever seen that have set up the results or that have graphically set up the results of moisture absorption or expansion frown ther MR. REYNOLDS: The next question is to neat changes. We clo not know that as far as Mr. Peters. If we omit the parapet, how do we thermal changes are concerned, there are fig- handIe sullen heavy rains, cannon In south- eastern states? M R . P E T E R S: We conic accomplish that through the design of the roof in directing the water to suitable downspouts, either sloping ures which vary all the way from, ~ think it is, .000003 to .00000S inches per foot. MR. REYNOLDS: The next question is to Mr. Noyes front Mr. Rearclon. Is reinforced brick masonry used extensively on the west 121
coast for single-story construction? How cloes it compare with (a) tilt up, (b) poured in place concrete, ~ c ~ gunnited walls? MR. NOYES: )'n] afraic! ~ cannot answer that. ~ have no connection with the west coast, any experience is entirely on the east coast, anc! we have not used reinforced brick work to its full extent. We have reinforced odds and ends here and there, but not to any great extent. Me. REYNOLDS: Now, here is a question from Mr. Rearclon of G.E. to anyone, but I'm going to address it to Mr. Myhre, because we were talking about the subject before the ses- sion began. If mortars are such an important part of tile masonry wall, ~ would like an expression , . . Ot opinion on masonry cements versus port- lan(l cement tinge putty, or hydrate lime. MR. MYHRE: ~ don't think T have ever been in a conference or in an assembly of engineers and architects where that question has not cone up. ~ awn going to give you nay own personal opinion. :Now, this can be taken for what it is worth, and it nest be consiclered my per- sonal opinion and not reflect on anything that anybody else is connected with. ~ think that high Tinge mortars are the most effective mortars. ~ do not think that masonry cements consisting of Portland cement and ground limestone will be suitable in most cases. ~ think that masonry units having a Tow moisture absorption characteristic could very well use that type of material. However, when the absorption rates become higher, we neec! the qualities that Tinge can produce in the mor- tar, and very- few masonry cements use Tinge, that is hydratec] Tinge, in their n~asonrv; mortar. MR. REYNOLDS: The next one is for Mr. i\:oyes. In your opinion, can money be saved in one- and two-story buildings-schools, offi- ces, etc. by using load-bearing n~asonr`; rather than frame structures? 122 MR. NOYES: Our experience with frame structures is rather meager in recent years. T don't think this question can be readily an- swereci. Many factors have to be taken into account, such as maintenance and various other angles. ~ believe that frame wouIc! be cheaper, but ~ don't think it would be as sat- isfactor,v. MR. REYNOLDS: ~ have two or three more questions of Mr. Myhre. Here is one from the Dow Chemical Company. ``What type of waterproofing do you recommend? What ma- terial do you use in expansion joints2" MR. MYHRE: There is only one water- proofer that is satisfactory in my estimation and that is the silicon waterproofer. None of the other waterproofers will approach it in sealing the pores and hair cracks in masonry walls. :[ know Dow makes that material as well as General Electric. We do not. Now, there are new truly elastic or synthetic n~aterials on tile market today which are a great deal better than the old oil-base type of calking compounds. T am referring to such materials as glycol. We ourselves are develop- ing one that we think will do the job at a little bit less money, possibly, than glycol. But these materials will last a great deal longer than the old compounds- four or five times longer, in our estimation. We have tested then for three or four years now and their con- dition is almost the same today as the day they were applie(l. We think the worIcT of them. It costs a little bit more when you first apply it, but the over-all cost is much less. MR. REYNOLDS: Now, Mr. Myhre, ~ have two questions here which T ant going to com- bine into one. Tile first one is can you describe the expan- sion joint or control joint as shown in your last stifle. And the other one is what is your rec- omn~enclation in regarc! to the use of through- wall control joints, in addition to expansion joints, for controlling cracks in long masonIv walls.
M R. M YHRE: When you leave walls con- rubber. or something that will cone back again sisting of a brick facing or some type of hollow when the wall shrinks, and is sealed on the masonry unit' we will say, for back-up, the type of joint is almost automatically designed. Of course, it must extend all the way through the wall. It cannot be just through the facing. We generally place then on colognes, so that both sides of the wall can be supported with flexible ties to the colognes. The joint is usually outside surface at least with a calking com- pound. Now, if the old type of calking con~- pounds were used, and that was the case in that last slide, it is necessary to protect that compound frown the weather. And that was the reason for the plate that you saw, which was fastened only on one side. It kept out the three-quarters of an inch wide as a minimum- rain and the sun and would make tile old type maybe a little bit more, depending on the of co~npoundlast tl~atn~uch longer. We don't length of the wall. The joint is sealed with an think they are necessary with the new elastic, very elastic, material, such as sponge materials. 123