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Les diagrammes suivants iilustrent la m^thode. 1 2 3 1 ■.''smeaneiiy .' afc'';!fi.^:»?^»ir*. MICROCOPY RESOIUTION TEST CHART (ANSI and ISO TEST CHART No 2) 1.0 I.I If 1^ 1.25 WWWA m 2.2 2£ I 1.8 1.6 ^ APPLIED IIVHGE I ST- "=^-5 Eost MO'H StrM! ^^S f'ochesler. N*.* ron. U609 USA '-S5 (^'6) 482 - 0300 - Phont ^= (^16) 288 - 5989 - Fa» mi' l'l;!Hli;!V CONKI'UllCDON in. n, 'iHKiii'.ii^^ MILL BUILDING CONSTRUCTION BY H. G TYRRELL. C. E. Bridge and Structural Engineer NEW YORK THE ENGINEERING NEWS PUBLISHING CO. 1901 h-f^.jiT^H\ Copyright. 1901. by THE ENQINEEUINO NEWS PUBU8HINO COMPANY TABLE ( )F CONTENTS. CHAPTER I. LoacL: Roof Loads — I-loor Loads — C .iie Loads — Snow ar^ Wind Loads— Miscellaneous Loads— Summary of Loads— Meth- ods of Calculation. CHAPTER n. General Desifni : Genera! Considerations— Walls— Roof Trusses —Spacing of Trusses— Jack Rafters— Roof Coverings— Truss Connections— Rafters — Bottom Chords— Purlins — Unit Stresses Lighting and Ventilation— Estimating the Cost. CHAPTER lU. Design of Structii ai Details: Foundations and Anchorages. Ground Floor 'instruction: Concrete Floors- -halt Floors Wood Floor —Floors or T- heds. Upper Tloor Construc- tion: Stcii Trough 1 ioors- rrugated Iron and Brick Arch Floors— Steel Girder and Timber Floor —Slow Burning Wood Floors. Roof Coverings: Gt — Asphalt Roofing — Slag ai: Roofing— Sheet Steel Rooh Roofing — Tin and Terne Plate . Rubber Roofing — Asbestos Ro Compantive Costs of Roofing. ?. Wall Anciiorages of Roof Trusses— tion — Gutters and Down Spouts. Cuiisi raiions — Slate Roofing iioofing— Corrugated Iron Hi iped Rooting — Steel R< ing — Metal Shingle Roofinf: ' — Wood Shingle Roofing — ellanpous Structural Details: ors a' d Windows — Ventila- iH963 CHAPTER i. LOADS. Mill biiililings diflfcr so greatly in character and purpose that it is impossible to formulate tables of dead weights which will suit all cases. The use to which the building is to be put, its location, the character of ihe roof covi-ring, the presence or absence of cranes, etc., ail aflfect the dead weight, and generally each case must be con- sidered indiviilually. For most purposes of design the loads may - divided into: (i) roof loads; (2) floor loads; (3) crane loads; (4) snow and wind loads, and (5) miscellaneous loads ROOF LOADS.— For making rough estimates the diagram of weights of roof trusses given in Fig. i will prove useful. hese weights have been figured separately nd do not quite agree with any of the published formulas. From this diagram, the table (Ta le 1.) giving the weights of roof coverings and the table (Table IIL) of wind and snow loads, the total weight to be carried is found. Were it possible to realize in actual practice the small sections re- quired, the weight • . trusses would be directly proportional to the lord carried. Iron purlins weigh from 2 lbs. to 4 lbs. per square foot of ground covered, according to the spacing of the trusses. Good practice in the United States requires that roofs in northern latitudes shall be figured for at least 40 lbs. per square foot of roof surface. FLOOR LOADS.— The Building Law of New York City re- quires that floors shall be proportioned to carry the following min- imum loads per square foot: Office buildings, 100 lbs.; public halls. 120 lbs.; stores, factories, warehouses, etc., 150 lbs!; rioors carrying heavy machinery, 250 lbs. to ^ j lbs. In every case the floor must bo strong enough to carry its maximum load. Mr. C. J. H. Woodbury, in his book on "Yh. l-ire Protection of Mills," gives a table of weights per square ;..u of fl or of vai s kinds of merchandise, which is reprinted herewith 1 . able I.) and which will be found v-J'-.oble in determining loads on floors CRANE LOADS.— For small traveling cranes of one or two tons capacity it is safe to consider the total weight of one end of the crane and its load as twice the capacity of the crane. For cranes TWO » *» » » TO flD WW wtlght of Boof -rvv.*^ pw w^ ♦. of Ami Covered. 4 MILL BUILDLVG CONSTRUCTION. ci!n?on nfn"''" ^'"^"• ^'^'^ '''' "^^•^'-"^ ^'^^t which will come on two carrying: wheels at one end of the crane wlien the uly oaded trolley is at that end. The corresponding CZ o aLtt^t^'iir"'^' '' ''"''''''' --'-' ^- "- --i>' - - the construction of the building. From the fig- ures in Table II. the strength of traveling crane runway girders and c olu m n s may be calcu- lated. The strains due to the pres- e n c e of jib cranes vary so greatly in num- b e r, character and intensity in different cases, that they do not admit of any general tabular statement. They must, however, be carefully fig- ured in each case and fully provided for in the design. The principal strains produced will be in the lower chord bracing of the roof trusses, columns. — * vv 60 10 Total WVigM- of Roof Thia«»» capacity 40 Ibe, ptr sq. ♦, Untt» E^XX^ BW. RtCh6"|«-#. Fig- 1. Diagrams Showing Weights of Roof Trusses. and the bending strains in the supporting SXOW AND WIND LOADS.-The pressure exerted bv wind on roofs ,s .n every case normal to the plane of the roof surface LOADS. - The amount of wind pressure usually assumed in proportioning framed structures is 30 lbs. per square foot on a vertical surface, which corresponds to a velocity of from 70 to 80 miles per hour. This velocity includes all storms except tornadoes, which cannot be provided fur. Table III. gives the normal pressures on roof sur- faces of different slopes for a pressure of 30 lbs. per square foot on a vertical surface. Snow loads of from 10 lbs. to 20 lbs. per square foot of horizontal projection uf the roof should be provided for. There are records of snow and ice deposits weighing 40 lbs. per square foot having lormed on roofs in northern latitudes, but this is a verv exceptional occurrence. When the roof has a pitch of 45° or more, snow load need not be considered. In Xew England latitudes, for roofs of ordinary pitch, it will be sufficient to assume 30 lbs. per square foot of roof surface for snow and wind loads combined. The maximum strains from wind and jib crane loads will so seldom occur together in the horizontal bracing that a combination need not be provided for. If they should occur at the same time, once in a year or so, the factor of safety will enable the metal to withstand the strain without injury. The overturning efifect of wind acting on the building as a whole and tending to revolve it about the bases of the leeward columns need be considered only in the case of tall narrow buildings. Wind acting on the sides of a building will necessitate the u^e of knee braces running from the columns to the bottom chords of the roof trusses, and the strains in these braces will be considerable. These strains will produce bending strains in the columns which must be provided for. MISCELLANEOUS LOAnS.— In special cases there will be other loads to provide for besides the more common roof, floor, crane, snow and wind loads just considered. The bottom chords of roof trusses are frequently employed to carry shafting, steam pipes, trolleys, etc. It is sometimes convenient also to have the roof trusses sufficiently strong to permit of a block and tackle being attached at any point to handle goods. The roof may re- quire a ventilator and when it docs this extra weight must be added to the roof loads. Columns in exposed places where they are liable to shocks from vehicles or merchandise should be made stronger than those built into brick walls. SUMMARY OF LOADS.— The total roof loads per square .at I ir.Tv^ 6 MILL BUILDING CONSTRUCTION. foot of roof, including weights of trusses for spans under 75 ft is about as follows for different constructions of roofing: style of ConatrucUon. , v. r, ■ ^'"- per »Q- ft. Corru^'ed Iron, unbearded „ " on boards ". ,', iSlate on laths H ^" " 1'4-ln. boards.'.'.".'!!.'.'.' ]^. Tar and gravel J'> Shingles on laths .'.'.'. J- Tile 10 20-30 When any of these roofs are plastered below the rafters 10 lbs per square foot should be added to the loads given. For soans ZTT ')r ^^-\ ' ""^'* °' ' ''''■ P" ^^-- ^-t should be added to the weights given. For snow and wind loads combined add for northern latitudes 30 lbs. per square foot to the loads given The weight of steel in the sides and roofs of mill buildings, with- out cranes, is from 4 lbs. to 6 lbs. per square foot of exposed sur- t'u! rim °'''^- ,^°'-'-"^^t^d iron sheathing weighs from I lb to 2 lbs. per square foot. These weights, with steel at ■; cts per lb., make the cost of steel buildings from 25 cts. to 40 cts per square foot of exposed surface. A rough approximate rule for calculating the extra weight of steel required in columns and girders when traveling cranes are used is as follows : Add 100 lbs. of steel per hneal foot of building for every five tons of crane capacity. This would give for a 5-ton crane an addition of 100 lbs. per lineal foot and for a 20-ton crane an addition of 400 lbs. per lineal foot. METHOPS OF CALCULATION.-Method.s of calculation will not be touched upon in this book, since they mav be found in any text-booK upon the subject. Briefly enumerated, the cases to be considered in determining strains are the following: (I) Strains in roof trusses and columns from permanent dead loads. {2) Roof trusses on walls, strains from wind normal to the sur- face. (3) Wind on side of building and roof, strains in trusses, columns and knee braces ; (a) columns hinged at the base ; (b) columns fixed at the base. Partial loading can never cause maximum srains in the parts of a Fink truss as they may in other forms of roof trusses. LOADS. TABLE I.-Showlng Weights of Merchandise as Given by C. J. H. Woodbury in his Boole on "Fire Protection of Mills." Wool in bale. 1^'° $? '^ ""' ""• •"■ Woolen goods oftJSlo Baled cotton Tii.^2i Cotton goods |^J°»^ Rags in bales ,■••"•,:, l^tn^ Strawboard, newspaper and manilla ^ttK Calendered and super-calendered book ^1 t^ Writing and wrapping paper .ik . ja Wheat "SI Flour "*" Corn Corn meal Oats Baled hay ia *« (jn •• Compressed hay and straw Vi " Bleaching powder |*.^ Soda ash Indigo Cutch Sumac Caustic soda Starch Alum iSxtract logwood Lime .„ Cement, American ii«* Cement, English '^ Piaster ^| '.'..'..".'.'.'.'.'.'.'.'.'■'■'■■■■Si ■ ■■■ 43 278 (K) 40 ■bai^s:.::: ]«t°23 ■■";; [[['.['.wi.'.'.i^'. TO 31 37 27 57 ' '•' one or more large bays or wide panels in the walls, in which ca le ends of the roof trusses coming over these bays must be supported on side or wall girders attached to the columns on each side of the bay. I Fig. 2. ROOF TRUSSES. — The Fink truss is the type most commonly used in the United States for the roofs of small buildings. It is economical because most of its members arc in tension and the 10 MILL BUILDING CONSTRUCTION. Fig.6. Fig.8. Figs. 3 to 8. Diagrams of Common Forifis of Roof Trusses. Struts are short. Fig. 3 is the form of Fink truss commonly used for spans of from 30 ft. to 40 ft. ; Fig. 4, the form used for spans of from 40 ft. to 55 ft. ; Fig. 5, the form used for spans of from 55 ft. lO 85 ft. ; and Fig. 6, the forms used for spans of from 85 ft. to 100 ft. If the slope of the roof is small, some form of English truss will be prefer- "■^j-^w^ ^-^ able fn the Fink truss, because .^y'\/\7 ^-^f^/ / '^ gives better intersection angles. If the roof is hipped it is necessary to have vertical members to which to fasten the hip rafters. Figs. 7 and 8, respectively, show a Queen truss and a Fink truss of th; same span and pitch, and both with vertical posts. It will be observed that the longest ver- tical strut in the Queen truss is avoided in the Fink truss. For small spans -p to say 30 ft., sheets of corrugated iron may be curved and provided with a single tie-rod across the bottom to form an arched roof. This construction can often be used to ad- vantage for ventilator roofs. The allowable slope or pitch of loofs depends upon the kind of covering or roofing employed. The allowable slopes for some of the more common roof coverings are shown in T Liie IV. It is more economical to employ horizontal bottom chords for roof trusses, or at least to keep the cumber down to an inch or two, since it avoids any bending of the bottom chord laterals. A truss whose bottom chord has a rise of two or three feet, however, pre- sents a better appearance. The neutral axes of all chord members should intersect in a common point at each intersection. Flat iron should not be used in roof trusses, except for connection plates, as it lacks the necessary stiffness. Steel is a superior material to tim- ber for roof trusses, because it is lighter, stronger and more dur- able. SPACING OF TRUSSES.— For the least weight of purlins the distance between supports must be a minimum, and since the weight of trusses is directly proportioned to the load upon them, the least total weight of trusses and purlins will be when ihe trusses are placed close together. This reasoning assumes that it is possible to rea'.ir.e practically the small sections required for the truss mem- PIP GENERAL DESIGN. I j bers, whicli it is plainly impossible to do. Experience shows that the most economical distance between centers of trusses for small spans up to say 50 ft., is from 10 ft. to 16 ft.; for spans e.xceeding 50 ft. it should be from one-fourth to one-eighth of the span, de- pending upon the nature of the roof covering and purlins. For plank laid directly on ra ;ers spacing should not exceed 8 ft. fc r 2-in. plank and 10 ft. for 3-in. plank. JACK RAFTERS. — Jack rafters need not ordinarily be used in mill buildings. When, however, the distance between trusses ex- ceeds 20 ft., it will be more economical of material to run a few heavy purlins from truss to truss to carry one or more jack rafters which in turn support the small purlins upon which the roof cov- ering rests. This construction was used in most of the buildings for the Columbian Exposition at Chicago and in many of the roofs for large train sheds which have recently been constructed. ROOF COVERINGS. — A great variety of roof coverings are available to the engineer. In selecting % roof covering the princi- pal things to be considered are the cost and the necessity or not of having it fire-proof Figures of slopes required for various ordi- nary kinds of roof coverings are given in Table IV. It should be remembered that the material requiring the greatest slope will re- quire the largest amount of covering. TABLE IV.— Showing Least Pitch of Roof Required for Various Kinds of Roof Coverings. Wood shingles on plank least pitch = '/« span. Slate, large '• " = V's •' " ordinary " " = Vi " " in cement " " = "n " Steel roll roofing " " = ',',2 " Rubber " " = Vn " Asbestos " " = '/ij " Asphalt " " = 'Aa " Corrugated iron, laid In cement " " = ' s " " " not laid in cjment " " = '/i " Tar and gravel flat Tin or terne plates " The building laws of the principal cities specify the conditions unvler which fire-proof roof coverings shall be used and also state what coverings are to be classed as fire-proof. Where this matter is not specified, the engineer must decide whether or not the risk warrants the use of fire-proof roofing, keeping in mind always that the cost of insurance on fire-proof buildings is less than for build- ings which do not come within this classification. When the risk is inconsiderable a covering of some of the best brands of roofing paper makes in every respect a first-class roof, since this material < "VM.-idR'ii •= zritm ifF- 12 MILL BUILDING CONSTRUCTION. T Fig. 9. i"gs where corro: ve ^sc/J: I 7 ir""" *'""°"" '" ""''"- boanls or have some kin I of IZ ,"'"'"^ *""'" "•= "'"< <"> .r™«e, of Ions spa,, where erec i„„ "" ' I e >« T"' ""' '" . p,a,es be.„een^he a„j ^ n, flangS 171 pnl pen, connecion,,. It ,„e ,oa-^''' but ordinarily .•».-hraei„,iri„r'es,r-;Xl":^tt:n^Trr;h; GENERAL DESIGN. 13 cost of manufacture. It is more economical to use simple shapes even at the expense of increasing the weights slightly than it is to in- troduce trussing. When the distance between rafters is more than about 15 ft. a line of J-in. rods should be run from the ridge through ihe purlins to prevent them from sagging in the plane of the rafters. At the gable walls a single angle ma . be built into the masonry and the purlins attached to it by clips as they would be attached to a rafter. The best way of placing angle purlins on a sloping roof is as shown in the sketch, Fig. loa. In this position it has a greater ver- tical moment of resistance than if tht roof leg were placed in a reverse posi- tion, as in Fig lob. To rivet the over- lapping ends of the corrugated iron on '^'CJ'Oa- both sides of the angle purlin, as si in the sketch. Fig. loc, and secunnc the covering to the angle by means 'FlgiOb. cf a bent iron, passing around the purlin, makes altogether a very much tighter piece of work than for a single clinch nail to be driven through the sheathing and bent around one leg of the purHn. In order to protect the overhanging corrugated iron at the eave from being battered and getting out of shape it is desirable to extend the upper chord angles of the trusses out far enough to receive an out- .^(•e purlin placed as nea.ly as possible at the edge of the sheath- ing. This overhang nred not be greater than 12 or 15 ins., and if a slightly better app .arance is desired a molded sheet metal cor- nice may be used. shown y^ ^curing y^^ A / fig. 10 c. 1^1 In UNIT STRESSES. — For dead and for live load stresses a factor of safety of four is sufficient. For greater combinations such as (lead, live, wind an:' crane loads combined, a factor of safety of three should be used. The temporary buildings for the Columbian Exposition at Chicago were proportioned for unit tensile strains of from 20,000 lbs. to 25,000 lbs. per square inch of section. LIGHTING AND VENTILATION.— A very efficient method of lighting mill buildings is to make the entire upper halves of the side walls of windows with the sash bolted to the framing. In buildings which do not require heating in cold weather, such as forge shops and ooiler houses, the lower halves of the side walls may be made of wood panels which can be eas-'y removed to allow a free circulation of air and to give clear space for the handling of '■SilP' ^AB5i*6«»:r='!-B'*-?'|ii^.-^-. qBH^^i i'SiS ■•'-.^ M MIU. BUILDING CONSTRUCTION vvuh open sides are us!.a,ly yS^o':„t"n;„";.^;;|- ^t forge shops or other buildings where there is considerable .as and l^^^L rT' '■°°' ""'' ""' ^^"^"^d --h more efficiem as a en Ulator by p acng a line of shutters about 2 ft. high in the ! de wa dIJt ■"■ °"Tt ''■'^" ^'^"^ ^''""-^ "^ opened an up hor roof """' ''^°"^' ''^"^ ^"^ ^^^ °P- ->es of the mon- A good common rule for the amount of windows required in the side of a buddmg is to make the window area one-fifth "he waU or say one-tenth of the total floor area. In place of removable wooden panels for the sides, corrugated iron doors may sometim be used to advantage. These are built to fill the whofe pane Tnd are counter weighted. They can be easily opened, but on account of the counter we.ghts and rigging for han^ng them, the cost U consKkrably more than that of wooden panels. If sash is used n nor should be Wide, say one-fourth the whole width of the building n order to allow light to reach the floor. This arrangem n o^ .de monitor however, does not secure so good ventilation. The upper part of the roof holds a considerable amount of dead air To overcome this a second smaller monitor may be placed along th ndge With louvres or shutters on the sides. This arrangement Will secure both a light interior and good ventilation. ESTIMATING THE COST.-It has already been stated that the weight of steel frames for mills and similar buildings is from 4 lbs. to 6 lbs per sq. ft. of exposed wall and roof surface; also that provision for traveling crane adds a weight of about loo lbs. per hn. ft. of building for every five tons capacity of crane Other material such as brick wall, roofing, doors, windows and floors is vei-y easily figured out in square feet. Hence, with the aid of the following table of prices, the approximate cost of the whole build- ing can be very quickly estimated. GENERAL DESIGN. IJ TABLE OP APPROXIMATE PRICES. Common brick work 25 to 35c. per cu. tt Rubble maionry *5 to If" per cu. yd Concrete f*> to #** per cu. yd. Cut Stone pier caps ♦- per cu. ft. PUet In place 25 ct». per lln. ft. Earth excavation 50 eta. per cu. yd. Steel trust and column frame In place 4 cti. per lb. Steel beam*. In place 3 Plain casting •_• -2 Corrugated Iron ..u. 22, In place, black 7 cts. per iq. tt. " " galvanized " " '■ Flashing, galvanized 15 " " Spruce luml^er. In place on floor or roof f25 per M. H. P. matclied, In place $35 " H. P. Joist and purllLS, on floor or roof $30 " Door frames and doors 50 cts. per sq. ft Window frames and window i .^.,.50 " Sash, glazed and painted 15 to 25 Gutter and conductor 2.' n. ft. Stairs. 3 ft. wide, wood step. Stairs, 3 ft. wide. Iron step. Rolling steel shutters 5*) sq. ft. Louvres, flxed 51' " Louvres, moving 75 " Corrugated Iron doors and shutters %' " Wire netting, galvanized l"* " Skylight, Vi-ln. thick glass 2.". Skylight, translucent falrlc 15 Pipe railing 50 c in ft. Round ventilators * >l«> eseh. Metal cornice 10 to 2.") er lln ft. Slate roof, not including boards $7 to $12 per 10 x !• ft. Slag and gravel roof, not includ'g boards. |5 " S7 Prep'r'd comp'slt'n roof, n't Incl'd'g b'ds |2 " 15 Wood shingle roof, not Including boards. $3 " 15 Tin plate roof, not Including boards 110 " |12 Corrugated Iron roof 17" f{> Roughly speaking, the cost of one-story iron h gs. rtim^*'te. is, for sheds and storage houses, 40 to 60 cts. p< sq. and for such buildings as machine shops, fr nes, plants, that are provided with traveling crani .he cc no to 90 Cts. per sq. ft. of ground covered. ;| i6 MILL DL'ILDIXO CONSTRUCTION, CHAPTER III. DESIGN OF STRUCTURAL DETAILS. FOUX NATIONS AND ANCHORAGE.— The subject of foun- dation cot. truction i.s such an extensive ont that it is impossible to consider it exhaustively within the limits assijjned to this book. It will he evident to all, however, that the design of foundations for the great majority of shop buildings is not a difficult problem, Fince the site selected for them will usually be in a location free from water and treacherous .soils. For the outside lines of columns either a continuous foundation wall, if the columns are close together, or, individual piers, if the columns are widely separated, may be employed. In either case the foundations must have ample area to distribute the loads over a sufficient area of foundation bed to ensure safety from settlement. The bearing power of (UfTerent soils is given in Table \'. If the building is large and any doubt exists as to the nature and quality of the foundation soil, soundings should be made and the bearing power tested by placing weights on a small known area. The bottom of the walls should always be carried to a sufficient TABLE v.— Showing Supporting Power of Various Foundation Soils In Tons per S'luare Foot. BeJrock (hardest) 20() (poor) ."J to 30 Dry clay In thick beds 4 Soft clay 1 Gravel and sand wel! cemented 8 Compact sand 4 Clean and dry sand 2 Quicksand and soft soils i j, d»»pth to make certain that the original bed Si. " is reached. A few layers of wet sand or gravel placed in the bottom of the excava- tion, filing it from side to side, and thoroughly rammed will help to distribute the pressure evenly. The wall or piers should have two good footing courses and the projection of each course bevond the one immediately above should be so small that the lower foot- ing will not be cracked by the bending strain from the load above. Each column should rest on a cut stone cap except ..here the load is so small that the foot of the column may rest directly on the reg- ular masonry without danger of crushing. The usual safe load for ' ."TriHtiW at.^ t lA- I Wim artt^k^lGBMtjy'^Jf-^rq^Bia', ■"-.fa •^~*"^**i -J* ■r'.Mis''"ii*^ ■'' r. ' .'..-Stit^^^i GROUND FLOOr _ . J8TRUCTI0.V. 17 Stone IS 250 lbs. per s.i. in. and for brick is 125 tbs. per sq. in. In the opinion of the writer hard brick or concrete are superior to stone for small foundations on account of their better bond. i'or very light loads a wooden box may be set in the ground and filled with concrete, the column ba.'j resting directly on the con- Crete or on a thin layer of cement mortar covering the top of the cuncrt-.'. In special cases of heavy loads on soft soil a grillage of concrete and I-beams .n- of concrete and railway rails will enable the load to be distributed over the requisite area with a saving over masonry. Where there is a tendency toward overturning, the column bases should be anchor-bolted to the foundation masonry. Generally the anchor bolts should extend through the masonry and be fastened on the underside. These bolts arc set in position by means of wooden templates and asonry is built up around them. In some cases a small -' • ,.,or set in the capstone, with sulphur or lead, will prcvn cient anchorage. It is the practici. ^f the writer in designing wall columns for buihhngs to consider the same rigidly fixed at the base, provided there is sufficient load on the column to hold it down. In some cases even though the load may be considerable, if the post is small there is still a liability to pin ended action. GROUND FLOOR COXSTRUCTIOX. CONCRETE FLOORS.-In the construction of floors as in other parts of the building the requirements of each case will de- termine the design and construction to be adapted. A very solid floor is made as follows: The soil is excavated to a depth of about 18 ins. and leveled up. Upon the bottom of this exca- •I'Cermni. 3'Con(reH. vation is placed a 6-in. layer of j^^'hi^ji broken stone which is thor- W^^^^^^^^^^^' Dughly rammed and the.; cov- ''^''^'Tr" ered with a layer of concrete 8 '''■ ''■ ^TTJ^T' '""" ins. thick. After the concrete has set it is covered with a wearing surface of cement 4 ins. thick. A combination of asphalt, Portland cement and sand makes a good wearing surface. T": ,• „ shows a section of this floor. ASPHALT I I rv RS »>;;i,alt floors are becoming very popu- lar where smah ost i ^ ncjt the t-ief consideration. Rock asphalt is limestone im -t-y .-?z .• tli i om 8^ to 17^ of bitumen. It is H^SSX^SEs .■*ix?- '■■<^\.~ 7^^ i8 MILL BUILDING CONSTRUCTION. found in many localities, but the principal workable deposits are at Limmer in Germany, Neuchatel in Switzerland, and at Seyssel in France. Less well-known deposits exist at Ragusa in Sicily, near Santa Barbara in California, and in Kentucky, Colorado, Utah and New Mexico. For shipping the rock is usually made into asphalt mastic in the following manner: The rock is ground into powder and heated in kettles with 8^ of Trinidad asphaltum added to pre- vent burning. The mixture is heated to a temperature of 350° and kept at that temperature for about five hours, being constantly stirred the whole time. The next step of the process is to mold the mixture into blocks weighing from 50 lbs. to 60 lbs. each. These blocks as purchased in the market always have the name of the mine from which they come plainly stamped on them. When mar- keted the mastic should contain 14^ of bitumen and 86;^ of caroon- ate of lime. To prepare the mastic for flooring it is mixed with Trinidad as- phalt and sand in the following proportions : Mastic blocks, broken, ... X'y "".... ^ ^ "''■ ' '^""'^'^^ asp'ialt, 4 fbs. ; fine gravel and l^^r^'-^-^- sand, 36 lbs. This mixture is heated for about '_ ■ five hours at 400° F., and is constantly stirred ^0- ''2- during the heating. At the termination of this Asphalt Floor wiOi Con- i,^-,.; ,i .. • i • , i , , . Crete Foundation. heating the material IS taken out of the kettles and spread. For a mill floor the asphalt should be spread i in. thick on a foundation of concrete or on boards. The concrete foundation should be 3 ins. or 4 ins. thick, and if boards are used they should be covered with a layer of sheathing paper before the asphalt is placed. Fig. 12 is a section of asphalt floor having a concrete foun- dation and Fig. 13 is a similar section with a foundation of wood. Any composition of coal tar becomes useless in a short time on account of the evaporation of the tar which causes the material to disintegrate and crumble away. Felt satu- I'AsphaH-; rtrper. rated with coal tar becomes brittle and finally useless. The oils of asphalt, however, are not volatile at any natural temperature, and hence properly prepared asphalt flooring composi- tion remains absolutely unchanged during years of exposure to the air and sunlight. Other important advantages of asphalt for flooring are that it is impervious to water and is so elastic that cracks do not develop. An asphalt floor has no joints to accumulate dirt and can be easily and thoroughly cleaned. It is pleasant to walk on, not tiring the feet as do stone 4'P!anH gnal^ "TW Fig. 13. Asphalt Floor with Wood Foundation. GROUND FLOOR CONSTRUCTION. 19 blocks or flagging. It is not worn away by traffic as are stone blocks, but is simply compressed. Asphalt flooring costs 16 cts. per square foot when laid i-in. thick, the cost running higher or lower according to the location and size of the floor. There are many imitations of asphalt made of coal tar and crushed limestone which it is almost impossible to distinguish from the genuine article, but none of these imitations has the properties of asphalt. These imitation asphalts will all crack and crumble after a few years' service. Asphalt is softened and finally destroyed by oil and it cannot, therefore, be recommended for floors subjected to oil drippings from machinery and materials. WOOD FLOORS.— A first-class wood floor is made as follows : Excavate the soil to a depth of 18 ins. and place a thoroughly rammed layer of concrete 8 ins. thick on the bottom. After this layer of concrete has set place 6x6-in. sleepers of pine or spruce 3 ft. apart c. to c. and fill be- 3' Pkink-4 Concrete..^ -gVg ?M:W¥1^. WW^- Fig. 14. Heavy Timber and Concrete Floor. tween them and flush with their tops with a second layer of concrete. For a wearing surface lay a flooring of 3-in. plank spiked to the sleepers. Fig. 14 is a section of floor of this construction. This floor construction is heavy and solid and will carry ordinary machinery without special machine founda- tions. A much lighter and cheaper wood floor may be constructed by embedding 3-in. plank or half-round sleepers in a layer of 6 ins. cr 8 ins. of cinders and spiking to them a flooring of 3-in. plank 3'Phnk-^ ^ ■e'gnder 'mm Fig. 15. Light Timber and Concrete Floor. (Fig. 15)- When this con struction of floor is used all machines must be provided with special foundations. Wood block pavement on a concrete foundation is a form of shop floor which has been considerably used, but the writer cannot recommend this construc- tion. FLOOR FOR CAR SHEDS.-Car sheds for electric railways require a special floor construction because of the pits beneath the tracks for the use of the inspectors and cleaners. These pits are from 4 ft. to 5 ft. deep. A common construction is to build brick ao MILL BUILDING CONSTRUCTION. piers nearty to tlie height of tlie floor level which carry timber sills, lo which the floor planking is spiked. W here wood floor.s are employed the preservation of the timber from decay is an important consideration. The best authorities on the question recommend the application of a coating- of lime 'A-'in. thick around the sills and on the bottoms of the floor planks. This protection should give the floor a life of 50 years. Mixing coal tar with the concrete makes a good preservative, or the concrete may be covered with tar wherever the floor timbers come in contact with it. Coating the sills and the underside of the planking with rosin is another excellent means of preventing decay. UPPER FLOOR COXSTRUCTIOX. STEEL TROUGH FLOORS.-There is probably no more sub- stantial a construction for floors above the ground floor than the riveted steel tror-ii construction known as the Lindsay floor. With this construction the floor boards may be laid directly on the metal or they may be spiked to small timber sills embedded flush in a concrete or cinder filling carried by the troughs, as shown by Fig. 16. The "Hand Books" published by most of the rolling mills give the safe load per square foot of trough flooring for vari- ous spans. CORRUGATED IRON AND BRICK ARCH FLOORS.— A cheaper construction of iron floor than the steel trough consists of corrugated iron arches sprung between I-beams and filled above with concrete in which the timber sills are bedded and planked over, as shown by Fig. 17. This floor has no spring. Corrugated iron sheets of No. 18 B. W. G., having a span of 6 ft. and a rise of 10 ins., have in actual tests sustained a load of 1,000 lbs. per square foot. Brick or terra cotta arches filled above with concrete is a floor construction which has been much used, but besides being heavy and expensive, this construction cannot be recommended for floors which are subjected to vibration from heavy running machin- ery. Fig. 18 is a section of brick arch floor. STEEL GIRDER AND TIMBER FLOORS.— A floor con- struction which has been extensively employed consists of a timber flooring carried by metal beams or girders. Fig. 19 shows one form of this construction, which consists of steel T-heams spaced 3 ft. or 4 ft. apart and capped with timbers to which a flooring of 3-in. or 4-in. plank is spiked. Another form of this construction is UPPER FLOOR CONSTRUCTION. 21 shown by Fig. 20, which consists of built up steel girders capped with plank and carrying timber joists to which the planit flooring is spiked. In this construction the girders are spaced from 10 ft. to 15 ft. apart. Another form of I-beam and timber floor construc- tion which is not much used in tliis country but which is a very effi- ■Cyndtrs ZUiypr s fhorinq SLaye rs Flooring P5f Cemgtrna Fig. 17 yCynelers Fig. 16. Fig. 18. ■ IT.:- ■( Vc&rhed Flmrmq Fig. 21. 5'Phnl, Fig. 20. Pig. 22. Figs. 16 to 22. Typical Upper Floor Constructions. cient construction for heavy loads is shown by Fig. 21. The I- beam joists are spaced the proper distance apart, which should be not more than 3 ft. or 4 ft., so that the depth of the wooden flooring may be kept at the minimum, and on them planks are set close to- gether on edge .md firmly spiked together. The top of this plank- ing is then covered with a i-in. coating of fine sand mortar and a wearing surface of matched boards is laid on top of it. SLOW BURXIXG WOOD FLOORS.— A form of floor con- struction known as "slow bu.niiiyf construction" is shown by Fig. 22. The principle of this construction, which is entirely of wood, is to concentrate the timber into the fewest number of large pieces so that a minimum surface will be exposed to the attack of flames. The construction consists simply of widely spaced heavy timber joists covered with a flooring of heavy planks. 22 MILiL BUILDING CONSTRUCTION. ROOF COVERINGS GENERAL CONSIDERATIONS.— The importance of having an absolutely weather-proof roof for shop buildings is evident with- out argument. The kind of roof covering employed determines in a large measure the possible pitch or slope of the roof. A roof with a steep slope sheds rain and snow more efficiently than one which is more nearly flat, but it has the disadvantage of a greater area and consequently of being heavier and also of presenting a larger surface to wind pressure. .\1! metal roofs are lightning- proof and because of their smooth surfaces are more easily kept clean by the wind and rain and the rainwater from them is likely to be more pure than that off a shingle or gravel roof. With these brief general remarks attention will be turned to the various forms of -)of coverings. SLATE ROOFING. — Roofing slates are usually from ^-in. to i-in. thick and of various sizes. The minimum slope of roof rec- ommended for slate covering is one with a 6-in. pitch. If the pitch is less than this water is likely to be driven through the joints in beating rains. If, however, the joints are laid in cement, the pitch may be decreased to 4 ins. or 5 ins. to the foot. Cement joints are advantageous in any case since they prevent the slates from break- ing and make the building warmer in winter and cooler in summer. A few courses of slate, with cement joints, are always advisable at the eaves and ridges and around chimneys. If the roof is exposed to the action of the corrosive gases, as is the case in chemical works, cement joints are imperative because any kind of nails will be de- stroyed after a time. Slate when well laid have a longer life probably than any other form of roof covering; they will last for 50 years or more. Slate make a firc-proof roof covering, but they will crack when exposed to heat and also if they are walked upon. Hard slate of a shiny ap- pearance are the best ; those that absorb water will be destroyed by frost. Slate may be laid on boards, on lath or directlv on iron purlins. \\ hen laid on wood they arc held in place by two nails, one in each upper corner. When laid on iron purlins they are held in place by copi)cr wire. For roofs of small pitch a lining of roof- ing felt will help to mal- t'le roof watertight. ROOP COVERINQS. 2^ The cost of nails for slate roofing varies with the market, but the following table is a fair average : 3d. galvanized slate nails, per liegr 15.50 4d. " " " 5.00 3d. tinned " " 5.7o 4d. " " " 5.25 3d. or 4d. polished steel wire nails, per keg 4.00 Copper nails, per lb 20 Slaters' felt in rolls of six squares costs $1.25 per roll ; two-ply tar roofing felt costs $1 per square, and three-ply $1.25 per square. Slaters' cement in 25-tb. kegs costs 10 cts. per pound. Shorter slates must be used for the first course at thj eaves and the final course at the peak. To give the first course at the eaves the same inclination or slope that the succeeding courses will have, a thin lath murt be laid under the slate at the edge of the eaves. A lap ol 3 ins. is the amount usually allowed and it should not be decreased. Slate does not make a cheap roof covering, be- cause it is heavy and requires a stronger framing to carry it, and be- cause the steep pitch required makes the area to be covered large. At present the Brownville and Monson slates of Maine and the Peach Bottom slate of Pennsylvania are the best and also the most expensive. The weight of slate per cubic foot is 174 lbs., hence the weight per square foot of different thicknesses of roofing slate is as fol- lows : Weight, lbs. Weight, lbs. Thi'-kness. per sq. ft. Thickness. per sq. ft. >/,-ln. 181 Vs-in. .5.4."? Vi.-in. 2.71 'A-ln. 7.25 V.-in. 3.02 An experienced roofer will lay about two (10 ft. x 10 ft.) squares per day of ten hours. The price of the best slate on board cars at the quarrico is from $5 to $7 per square, according to size and color. Red slate costs from $10 to $12 per square, and ordinary slate, black, purple, or of mixed colors, cost from $2 to $4 per square. These prices include punching and countersinking the nail holes. Table \T. gives the number of slate per square, using 3-in. lap for various sizes of slate. TABLE VI.— Showing Number of Roonng Slate of Different Sizes and 3-in. Lap Required per Square of 10 x 10 ft Size, No. in each Size, No. in each Size, No. in each ins. square laid. ins. square laid. ins. square laid. 6x12 5.S3 0x1(5 247 11x22 138 7x12 457 lOxKi 222 12x22 120 Sx12 400 0^18 214 12x24 115 7x14 3:4 lOxlH na 13x24 106 Sxl4 .'W7 lOx'JO 170 14x24 98 9x14 201 11x20 154 8x16 277 12>c20 142 I 1 H MILL BUILDING CONSTRUCTION. ASPHALT ROOFING.-Asphalt roofing for flat roofs is ap- p led as follows: (i) One or two layers of felt paper ; (2) a coating of asphalt roofing cement : (3) a laver of roofing felt ; (4) a fi-ial coating of asphalt cement into which is rolled clean sand and fine gravel. I- or pitched or sloping roofs the layers of roofing felt al- ready cemented together by the first coating of asphalt cement are sold in rolls about 36 ins. wide. This covering is laid in courses with the edges overlapping about 2 ins. and fastened with the nails and tin washers. When laid the roofing is covered with the final coating of asi)halt cement and gravel. A canvas bottom laver may be used in place of the first layer of paper. This form of covering with the top covering and gravel complete and ready for laying is sold for $3.50 per square of 10x10 ft. - ^ t. The principal advantage of any kind of asphalt roof covering is that It is perfectly water-proof, and after being laic' it does not crack or peel off like tar and does not run at anv natural tempera- ture. W hen graveled over it makes a practicailv fire-proof roof- ing. I-inally, it is easily applied by unskilled workmen. SLAG AXD GRA\EL ROOFIXG.-SIag is preferable to gravel or .hese roofs because of its lighter weight. The construc- tion of both Slag roofing and gravel roofing is as follows : (i) Three layers of felt paper are fastened to the roof; (2) a coating of tar is applied to the top layer of felt ; (3) two layers of felt paper are laid on the tar; (4) a covering of tar is applied to the top layer of the second course of felt u.-ing about eight gallons of tar per 10x10 ft square, and the slag or gravel is rolled into the tar. This form of roof covering should last from 10 to 20 years. It is fire-proof needs no pamt and refracts the heat. It is noiseless and is not af- fected by gas. acids, etc. Finally, it is a comparativelv cheap cover- ing, costing 5o>' less than tin CORRUGATED IRON ROOFIXG.-Corrugated iron is made from sheet iron of standard gages by stamping, one corrugation being stamped at a time. As there are no sharp joints to be made there is no advantage in using sheet steel. The corrugated sheets are made in lengths increasing in dimensions by even feet from 5 ft. to ID ft., inclusive, and of such width that they lav 2 ft. even on the roof. The sizes of corrugations made in the United States are 5 ins., 2^ ins., i} ins., f-in., and 3-16-in. c. to c. of corrugations. The 24-in. corrugation is the size most commonly used. Table Vn. gives the costs and weights of both black and' galvanized iron ROOF COVERINGS. 25 for Dirniingliani Wire CJage and the new American Standard Gage adopted by Congress in 1893. TABLE VII.— Showing Cost and Weight per 10 x 10 ft. Square of Painted and Galvanized Corrugated Iron. Gage. 2,H 27 2ti 24 «>•> 20. . . . 18 10 I — Painted Wt.lbs. Price persq. persq. *.i.oo 3.20 ;j.,so 7.20 U.UO Birmingham. I — Galvanized. — 1 Wt.lbs. Price HI its 12:{ l.-.:{ 214 2S3 persq. 8.' !I4 101 114 141 1,S8 221 287 per sq. $h!4<» 5.(;o (i.80 8.40 ll.tlO 15.20 -American.- I— Painted. — , Wt.lbs. Prlie per sq. 1*1' 7" 84 111 138 105 220 i-GaIvanized.-| Wt.lbs. Price per sq. $2.t)(» 3.10 3.30 4.15 4.90 o.m 7.40 8.00 per sq. 80 113 99 127 154 182 23t; per sq. !?4.i«) $5.30 5.50 t;.4<) 7.40 The prices given in Table VII. are for small lots ; for car bad lots the prices will be about lo-f less. This table also refers to 5-in. 2^- in., and 3-16-in. corrugations; for i^-in. and |-in. corrugations, $^ should be added to the weirhts and prices given. If painted with asphalt or graphite instead of iron oxide, the cost will be 25 cts.more per 10x10 ft. square. Wire nails cost 10 cts. per square; galvan- ized nails cost 15 cts. per square and cleats and bolts cost 25 cts. per square. The price of curved sheets is 20% more than that of straight sheets. Hg.es. The sheets of corrugated iron should be laid with a lap of 4 ins., as shown by Fig. 23, when used for covering side Fig.84.. walls, and with a lap of 6 ins., as shown by Fig. 24, when used for roof covering. When laid on wood sheathing corrugated iron covering is lined with water-proof paper and fastened with 6d. nails, using about 25 nails per sheet. \\'hen laid on iron purlins for boiler houses or anywhere that water is likely to collect on the underside of the cor- rugated sheets, a lining of the following composition may be em- ployed: (i) Wire netting tightly stretched over the purlins; (2) asbestos paper ; (3) tar paper ; (4) asbestos paper ; (5) tar paper ; and (6) the corrugated iron roof covering. When corrugated iron is laid over iron purlins it may be fastened to them by clinch nails bent around the purlins, as shown by Fig. 25, or by cleats of ^-in. hnnp iron 2I in';, lorsrf riveted or hoUcd to the sheets and to the pur- lins. Generally, however, cleats of this form are used especially with channel or Z-bar purlins. The clinch nails or cleats should be placed about 5 ins. or 6 ins. apart and care should be taken to con- 4 I a6 MILL BUILDING CONSTRUCTIOK. nect them always to the tops of the corrugations, as shown by Fig. 25. The following table shows the size of clinch nails to be used Fig. 26. Clinch Nail Fastening for Corrugated Iron Roofing. with different sizes of angle purlins and also the number of nails to the pound in each instance : Purlin angle 2 x 2 Ins. 2V,x3ina. SMjxavilns. 4x4>/.lns Length of nail 4 Ins. 5 Ina. « 8 ."."i 1.0 U. S. Standard, Galvanized . . .84 .'JO l.ic Gage. Oi) 1T2 1.31 1.2.-) - 41 20 1.40 1.7.% l.«« 18 lit" 2.0 $3.10 per stpiare painted and ?5.50 per scpiare palvanizcd. I'o. uir load lots lo'/ should be de- ducted from the above prices. STEEL ROLL ROOFIXC-Steel roll roof^nj? differs from steel sh.-et roofing by having the sheets of 8 ft. and 10 ft. length jomcd at the factory into a continuous piece some 50 ft. long As the side joints nuist be made after the material is laid out on the roof this roofing is more suitable to roofs of small pitch, say i in to the foot, than to steeper roofs. Steel roll roofing is easily han- dled and the cost of-shipping is less than in the case of steel'sheets which have to be boxed. Parrafintd felt packing should be in- serted in the joints. If desired the manufacturers will make stee! roll roofing in any length retjuired up to 150 ft. to sui' the length of roof to be covered. This roofing weighs about 85 fts. per 10x10 ft. square and in sheets of Xo. 27 R. W. G. it costs $3.30 per square pa-ntcd. and $5.90 per s(|uare galvanized. Steel roll roofing re- quires no ridge capping since the strips or rolls are continuous over the ridge. Generally the manufacturers of an> kind of steel roof- ing having folded joints provide special tools for laving it. TIX AXD TERXE PLATE ROOFIXG.-Tin and tame plate riofing are generally used only for flat roofs or roofs with a small pitch. The plates come in i4x2o-in. and ^Sx2o-in. sizes and well laid plates of good quality should last 30 vcars. It is very im- portant to the life of the covering that its joints .should be well sol- dered and that there should be no travel on the roof. Tin and tcrne plates may be laid on sheathing or over old shingles. If the roof is quite flat all joints should be soldered, but when laid on sloping roofs the side joints may be folde.l aiul the cross or horizontal joints soldered. Some roofers lock all joints and fill the horizontal seams with lead. The sheets are fastened to the roof bv cleats; if the side joints are soldered the cleats should be soldered in the joints. For sloping roofs it is often convenient to have a number of sheets jointed in the shop into strips of the right length to reach from the eaves to the ridge. After laying the plates should be nnsntc.-] xvith two contf, of paint and they slunild be repainted about every two years afterward. To reduce the noise, tin or terne sheet roofing may be laid a lining of tar paper. The old method of preparing tin or terne plates was to immerse ROOF C0VERIN03. 29 tlie sheet of ir n or steel in a bath of tin or lead, a coatinp of which adhered to the plates when they were removed. The nodern method o. manufacture is to pass the sheets between rolls which are immersed in a batti of tin or lead, and thus by adjusting the rolls to secure a coating as thin or as thick as may be djsired. The cost of the finished plate depends largely upon the thickness of the coat- ing. Plates coated with lead are called ternes and are somewhat cheaper and less durable than tin plates. Terne plates are more generally used for roofing than tin plates. The best plates are made from charcoal iron, but Hessenier steel is also used. The thickness of sheets commonly employed are known as I C and I X, and correspond to No. 30 and Xo. 28 B. W . G., respectively. MET.\L SHINGLE ROOFING.— Metal shingles are made either of tin or terne plate or of sheet steel painted. They possess the regular advantages of metal roofing, being fire and lightning proof, of light weight and not being easily cracked or detached. Like shingles of any kind they cannot be laid on fiat roofs. They are manufactured in a great variety of sizes and forms to fit differ- ent kinds of sloping roof, are durable and present a fine appearance. Metal shingle roofing weighs from 90 fts. to no lbs. per 10x10 ft. square. RUBBER ROOFING. — Rubber roofing is made of felt paper soaked in a preparation of rubber and then rolled. It is put up in rolls 32 ins. wide and is laid lengthwise of the roof and fastened either with strips running up and down the roof about 2 ft. apart or with nails and tin washers. After being laid the roofing is coated with two coats of slate paint, the upper coat of which is sanded. Rubl)er roofing is very cheap and is especially suitable for tempo- rary roofs or for sheds where an expensive covering is not required. When painted it does not take fire easily, and it can be laid on roofs having a pitch as flat as 2 ins. to the foot. It does not make a hot upper story as some other coverings do. The slate paint does not contain tar and so will not crack or peel off, and it is very elastic. The color is chocolate brown. As usually laid the layers are lapped about 2 ins. The cost of rubber roofing complete as described, in- cluding nails, painting and sanding, runs from about $2.50 to $3.75 per 10x10 ft. square, according to the thickness of the felt paper used. ASBESTOS ROOFING. — Asbestos roofing is made of canvass coated on both sides with a water-proof composition and lined on the bottom with Manilla paper and on the top with asbestos felt. It |§ MILL BUILDING CONBTRbOTION. is laid in horizontal courses and fastened with nails and tin washers, and afterwards it is coated with asbestos paint. Asbestos roofing weights complete as described about 85 lbs. per 10x10 ft. square and costs about $4.50 per square. The covering re ,uires occasional repainting, the paint costing from 40 cts. to 50 cts. per gallon and one gallon covering about 100 .scj. ft. Asbestos cement for stop- ping leaks and calking around chimneys costs from 5 cts. to 10 cts. per pound. Asbestos building felt in rolls 36 ins. wide weigh- ing about 70 lbs. per roll costs about 12 cts. per pound. This papci- runs 6 lbs., 10 lbs., and 14 lbs. in weight for thin medium and thick paper, respectively. Another paper made from long libered asbes- tos costs about 15 cts. per pound. WOOD SHIXGLE ROOFING.— According to Kidder's "Ar- chitects' Pocket book": "The average width of a shingle is 4 ins. Hence when shingles are laid 4 ins. to the weather, each shingle averages 16 sq. ins., and 900 will cover a square. If laid 4J ins. to the weather, 800 will cover a square ; if laid 5 ins. to the weather, 650 will cover a square ; and if laid 6 ins. to the weather, 600 will cover a square. This is for com- mon gable roofs. In hip roofs where the shingles are cut more or less to fit the roof, add 5^. A carpenter w'll carry up and lay on the roof from 1,500 to 2,000 per day, or two and a half squares of plain roofing; 1,000 shing'.cs laid 4 ins. to the weather will require 5 lbs. of shingle nails." When cost will permit and the roof is not steep shingles should Lt laid in J-in. of mortar, as the lim.e prevents decay. The life of shingles is greatly increased if they are dipped in paint before being laid. COMPARATIVE COST. — The comparative approximate cost per square of loxio ft. of the several kinds of roof covering which have been described is given by Table IX. TABLE IX. — Giving Comparative Approximate Coet per 10 x 10 ft. Square of Ditfereot Roof Coverings. Slate on Iron purlins $2.fK) to J7.00 per sq. Metal tile, tin 8.50 " 9.75 " " steel, lead-coated 10.75 "1,3.75 " Rubber roofing 2.00 " 3.75 Felt and gravel ♦L.^O " Ornamental tile 40.(K> " fiO.OO per M. Tile shingles 21.00 " 35.00 " Charcoal tin plates, I.e., 14x20 Ins 0.00" 0.50 per box of 112. I.e., 20x28" 12.00 " l.TOO I.X., 14x20" 7..T0 " S..-K) IX, 20^2.'«" i5nrt"i7.(X) Coke plates, tin, I.C, 14 x 20 Ins n.-V) I.e., 20x28" 11. ,50 "12.00 I.X., 14x20" 7.50 Charcoal plate, terne. I.e., 14x20 Ins.. . . 5.50 " I.e., 20 x2,S " ....10.75 "11.00 " I.X., 14x20 " fi.40 " I.X.. 20x28 " 12.80 SII8CELLANE0VB STRUCTURAL DETAILS. 3» ■.nrii F;g. -M. Fig. 30. MISCELLANEOUS STRUCTURAL DETAILS. WALL ANCHORAGES OF ROOF TRUSSES.— There are several methods of anchoring roof trusses to the side walls of build- ings. Fig. 26 shows the standard anchorage in which the lower chord of the truss is connected by boltr. to the projecting end of a plate built into the wall masonry. Fig. 27 shows an anchorage con- sisting of bolts set into the wall and at- tached to a washer plate at their bot- toms. Fig. 28 shows a similar anchorage with the washer plate omitted and the bolts held in the masonry by cement. Fig. 29 shows a method of attaching the truss to the side of the wall. As shown by the draw- ing, the anchor bolts pass through the wall against the outside of which their heads secure a bearing by means of a washer plate. The area of this washer plate in square inches shouM equal eight times tlie tension on the bo;:> in tons. It is important also that the end of the truss should fit tight to the wall, shims being used if necessary to ensure such a fit. The following table shows the diameter of bolt to be used for walls of different thicknesses ; the washer plate area in square inches to be allowed for each bolt, and the holding value of the bolt in tons: % iU'>^\ ^ ^ Fig. 31. ■IRovqhBolfs stt in Ctmtnf I'm Fig. 28. Figs. 26 to 32. Fig. 33. Typical Wall Anchorages for Roof Trusses. Dlam., S-lQ. wall, 12 -iii. wan. IC-In. wall, 20-tn. wan, Area or plate in>. tons. tons. tons. tons. sq. Ids. §:::; 0.5 0.7 • . . 18 O.fi 0.9 1.0 . . . 26 %• • 0.7 1.05 1.4 . . . 36 1 08 1.2 1.0 1.77 46 i 32 MILL BUILDING CONSTRUCTION. Wlicn it is inexpedient to pass tiie anchor holts throiifjli he wall, as shown hy h'v^.- jy. the anchorafje is accomplished hy inserting ex- pansion holts into the wall. The following taljle shows the holding power of expansion holts of different sizes: Diam., ins. I Hfildins power in loiia tor Irngrha of- i ins. C, ins. ,S ins. • .■ ■■ .JS 0.42 (l.nc. tt.Tn (•.47 o.r,.-i (i.sj <)..")- it.ir, (i.iK! !•_' ins. 1.1:.' Fig. 30 shows the end of the truss l)u.':. 1 :.j> *';..■ v;all, the angle clips serving as anchors. Fig. 31 shows the method of anchoring a beam bf.ilt into the wall: the length of the rod should equal the width (jf the beam flange plus 6 ins. I'ig. 32 shows the man- ner of nnchnriTig chnnnc! heatii wall struts. The anchor holts shotdd he spaced about 3 ft. apart. If the struts are to be anchored to a wall already built the holts should be run through the wall with washers on the outside, or expansion bolts may be used. DOORS AXD WIXDOWS. — Xarrow doors may he made without center styles and wide doors should have two or more spaced from 3 ft. to 6 ft. apart. The rails and styles should be halved together, and they and the diagonals also should have a J-in. chamfer; the sheathings should be screwed on. Fig. 33 shows a door of the construction described. Tables X. and XI. give the proper sizes of material and hardware for doors of different sizes. Fig. 33. Construction for Narrow Doors. TABLE X.— Showing Proper Sizes of Material for Doors up to 14x20 ft. In Size. Size of Doors. Styles. Id ft. Ins. 5 X S or less -ix W* 5 X 8 to 7 X S 7xlW 7 X 8 to 10 X 10 7xl(<. 10 x 10 to 14 X 14. ..8x2 " 14 X 14 to 14 X 20. .0x2% 1 ■■'■ ■ Top. Center. Bottom. Diags. Sheath Ins. Ins. Ins. Ins. Ins. 4x114 4x114 (ixn4 4xlV4 4x% 7x114 ♦i X 114 8XIV4 4X1H 4x% 7x11^ tixlVi SxlH 4xlV. 4x% 9x2 8x2 10x2 5x2 4x% 9x2Mi 8 X 21,^ 10 X 2Vj 5 X 2Vi 4x% HS MISCELLANEOUS STRUCTURAL DETAILS. 33 ^~" w 1 — '*•■ .r> i, ^J% ^ i r,r- ^li'tij'Bncilhtlnrytr OmlHd ir Chmf li> H> lii .,i 24-ia. strap hinge Vi-ln. lag screws JO-ln. " " 30-in. " " Size of doors. Ft. ." X f> or less. . !! X t! to a X M.. 3 X S to 4 X 10. » X 10 to ox 12. Over 5 X 12. . . I — Screws. — | Uoor. Jamb. Ins. Ins. i:!4 - Doors of Holts. Ins. Mi Fig. 34 sliows tilt details for a side window in a bricl< wall. Us- ing ioxi2-in. glass, these windows are usually made with from 24 to 40 lights or panes. The sizes of wall openings required for win- dows with from 24 to 40 ioxi2-in. lights, are as follows: No. of lights. 24 2.S ;i2 40 Size of opening. .4 X 7 ft. .4x8 ft. 1 in. .4x!tft. 1 in. .4 ft. 10 ins. xOft. 1 in. Louvi^s Rcund Ven+llcTtt)rs Fig. 37. '0 40 -1O % •>; 1,.', RoLnd venir. i\ .-. 4 Louvre vent^. 8 7 »; L-.uvre or open vents. FiRs. 35 and 36 shows details of window construction in the side wall of an iron frame building covered with corrugated iron. VENTILATORS. — Ridge ventilators may be in the form of a luonitor roof or they mav -^¥>. --^^~^ be round ventilators placed at intervals (Fig. ' ^/). The area of ventilators required i)er 100 sq. ft. of floor surface for shop buildings of various kinds is given in square feet by the following table : Height, in ft., above gioiir.d. 20 Machine shr^p, sq. ft % .Mills, sq. ft 7 Forge shop, sq. ft f> The areas given in this table are net areas and when louvres are used 6o;if should be added to allow for the obstruction of the open- ing by the slats. The areas in square feet of round ventilators of different diameter are as follows : Diameter, ins 12 IcS 24 3(3 38 42 48 Area, sq. ft 0.8 1.8 3.1 4.0 7.1 ll.li 12.0 Details of a monitor roof ventilator with louvres are shown by Fig. 38. Fig. 3Q shows details of a monitor roof ventilator with hinged flat iron shutters. These details are for a shutter 8 ft. long. Ordinarily, shutters should be made 6, 7, 8, 9 or 10 ft. long, but in- termediate lengths may be used if necessary. The width of the shut- ters should be the same for all lengths. The shutters may be either mi3'::el.laneous structurau dbtails. 35 kr-'K 4k' i—LeurreBIXK Bolt with LtwneyJ^y^/'rshin^ S ash Fig. 38. Monitor Roof Ventilator with Louvres. Flashing'-- K' -gr - -l'>L,}i?ii' 8"^ ? This Hole h. Wtd Cabk over O'O'lmj Finish ~-rio'~ This Dcrrtensian tvbf din. Ifis them Len^h sf 5huttcr .ji^ ^^^T^ h Laying o/tiinH- \ " lalm locirtt S^a •Purlins in f)vper NT* _ s/ton to Fit Bnel \^ of Standard Vmtilation J flashing, / SlKith for Con- har list 6iyr Dimensi on li \,itf. /y^im-L,yri^r I Steel Spring i §"Tie-8eirm Hook Fig. 39. Monitor Roof Ventilators with Hinged Flat Iron Shutters. !r I . J-Jl I , i UM. 36 MILL BUILDING CONSTRUCTION. Kig. 40. Montior Roof Ventilator with Fixed Sash. Fig. 41. IVIonitor Roof Ventilator with Movable Sash. ')^m MILL BUILDING CONSTRUCTION. 37 Fig, 42. y-d'Spiking Piecf ^— aiM,;iiiMTTTTm— ^ 'T -!■— '— Fig, 43. Figa. 42 and 43. Monitor Roof Ventilators with All-Wood Framiig. 38 MILL BUn DINQ CONSTRUCT ON. Detail of Lap Joirrt-. Detail of Lock Joint. Detoil of Copped Joint. Method for Faatning Ends of Wira. Fig. 44. Monitor Roof Skylight of Translucent Fabric. [ctjn of Sheets Rm-fetl together here^ Zlayers Tar fbpcr \ ..-Corruqatett Inn Oetail ! dLayenTarfinxr Net Lei \^i xpil' of Single 6irtt«r Next Wall. Specimen Drawing of Gutter Angles. Detail of Doobte or \bll«y Gutter. Fig. 45. Single and Double Gutters Detail of Gutter Yvi* C, Purlins. MILL BUtLDlNQ CONSTRUCTION. 39 Hanging Gutter fcrgsr"* Patent Adjustable Hanger. For Hanging Sunrr3,Punch ^' Holes in B/rlin to fake Honors. Out fdjp of Oulter must net Extend aboa Boof plant prolonged. Hcmgti Hanging ©utt-ers "D-B." ^justable Strap Hangsr. Details cf Box Outt^r. Fig. 46. Types of Fixed and Hanging Gutters. 40 MILL. DUILUING CONSTUUCTION. of !)lack iron or palvanizd iron. If galvanized iron is used all cover- ing and flasliing for the ventilator roof, sides and ends, and all bolts, clips, clinch rivets or other fa.steninf,'s, any part of which shows on the outside of the covering or finishing,', should also be galvanized. Fie 40 shows a monitor roof ventilator with fixed sash and all . on framing, ami Fig. 41 shows a similar construction with mov- able sash. Figs. 42 and 43 show monitor roof ventilators with fixed and swing sash, rcspectivcl... all wood framing. Fig. 44 shows a skylight on roof of monitor made of translucent fab- ric. It should be noted that the roofing sheets run lengthwise of the building and are 6 ft. 3 ins. x 3 ft. 3 ins. in size. This .size of sheet shouhl be used whenever possible, although sheets may be readily cut to smaller sizes. The widtii of the lap should be 2' ins. and both edges should be securely fastened. I'or fastening the fab- ric wire nails il-in. long, or 3d nails, should be used; the amount required being i^ lbs. per loo ft. of seam. Lap joints or lock joints can be used for all seams, but capped joints can be used only for seams running in the direction of the roof slope. GUTTERS AND DOWN SPOUTS.-Thc sizes of gutters and down spouts and their distance apart for roofs with \ pitch and of different spans are shown by the followii'g table : Vj root span, ft. Size of Kutter, ins Size of down spouts, Ins. .. Spacing of down spouts, ft. 10 liO a<> W ,-)(» m 70 8<) . . o r> 1; « 7 7 .S 8 . . ■■« 3 t 4 .- r, 1; «i .50 50 :A) 50 40 40 40 40 The slope of gutters should be at least i ft. in 50 ft. When the length of the roof overruns the spacing more than 10 ft. an extra down spout should be put on. Fig. 45 shows details of single and double gutters with both an- gle and channel purlin conncci. ms, and Fig. 46 shows diflferent forms of hanging and box gutters. Regarding hanging gutters it may be noted that ordinarily gutters should slope i in. in 15 ft. A 6-in. gutter takes a 4-in. leader and will drain about 3,000 sq. ft. of horizontal surface. A 4-in. gutter will take a 3-in. leader and will drain about 1,700 sq. ft. of horizontal surface. Hangers for hang- ing gutters should be spaced about 2 ft. 6 ins. apart.