Part 14

DATA FOR ESTIMATING SHINGLES ===========+===========================+=========================== | Number of Square Feet of |Number of Shingles Required Exposure to| Roof Covered by 1,000 | for 100 Square Feet Weather | Shingles | of Roof Inches +-------------+-------------+-------------+------------- |4 Inches Wide|6 Inches Wide|4 Inches Wide|6 Inches Wide -----------+-------------+-------------+-------------+------------- 4 | 111 | 167 | 900 | 600 5 | 139 | 208 | 720 | 480 6 | 167 | 250 | 600 | 400 7 | 194 | 291 | 514 | 343 8 | 222 | 333 | 450 | 300 ===========+=============+=============+=============+=============

White-pine and white-cedar shingles are graded alike. The shingles made of No. 1, or clear, stock are designated XXXX. Those made of No. 2 stock, with 6-inch clear butt, are given the brand XX, while those made of mill cull, with sound butt, are called X.

Red-cedar shingles are graded differently. Their grade depends on their length. Thus, 18-inch, No. 1 shingles are termed “Perfection,” while 18-inch, thin butt are termed “Eureka.” Red-cedar shingles 16 inches long, if made of No. 1, or clear, stock, are designated “Extra * A *.” If they are 16-inch, thin butt, they are termed simply “* A *.”

Sawed shingles are made up into bundles of 250, and are sold on a basis of 4 inches width for each shingle. Shingles cost from $4 to $6.75 per thousand, according to material and grade. Dimension shingles—those cut to a uniform width—if of prime cedar, shaved, ½ inch thick at the butt and ¹/₁₆ inch at the top, will cost about $7.75 per thousand, but since such shingles are usually 6 inches wide, less will be required per square.

A fairly good workman will lay about 1,000 shingles per day of 8 hours, on straight, plain work; while in working around hips and valleys, the average will be about 700 per day.

=58. Slating.=—In measuring =slating=, the method of determining the number of slates required per square is similar to that given for shingling; but in slating, each course overlaps only two of the courses below, instead of three, as in shingling. The usual lap, or cover, of the lowest course of slate by the uppermost of the two overlapping courses, is 3 inches; hence, to find the exposed length, deduct the lap from the length of the slate, and divide the remainder by 2. The exposed area is the width of the slate multiplied by this exposed length, and the number of slates required per square is found by dividing 14,400 by the exposed area of 1 slate in square inches. Thus, if 14" × 20" slates are to be used, the exposed length will be

20 - 3 ------ = 8½ inches; 2

the exposed area will be 14 × 8½ = 119 square inches; and the number per square will be 14,400 ÷ 119 = 121 slates.

The following points should be observed in measuring slating: Eaves, hips, valleys, and cuttings against walls are measured extra, 1 foot wide by their whole length, the extra charge being made for waste of material and the increased labor required in cutting and fitting. Openings less than 3 square feet are not deducted, and all cuttings around them are measured extra. Extra charges are also made for borders, figures, and any change in color of the work; and for steeples, towers, and perpendicular surfaces.

Table XI, which is based on a lap of 3 inches, gives the sizes of the American slates and the number of pieces required per square. The cost of slating varies from 9 to 15 cents per square foot, depending on the class of work.

The thickness of stock slate varies from five to 1 inch to ⅜ inch and special thicknesses up to 1 inch are made to order. For ordinary dwellings, the usual thickness used is five to 1 inch, which gives a thickness of a little more than ³/₁₆ inch, and the size used for this class of work is generally 8 in. × 12 in. or 9 in. × 18 in., the price being the same.

TABLE XI

NUMBER OF SLATES PER SQUARE ========+=========+=========+=========+=========+========= Size |Number of| Size |Number of| Size |Number of Inches | Pieces | Inches | Pieces | Inches | Pieces --------+---------+---------+---------+---------+--------- 6 × 12 | 533 | 9 × 16 | 246 | 14 × 20 | 121 7 × 12 | 457 | 10 × 16 | 221 | 11 × 22 | 138 8 × 12 | 400 | 9 × 18 | 213 | 12 × 22 | 126 9 × 12 | 355 | 10 × 18 | 192 | 13 × 22 | 116 7 × 14 | 374 | 11 × 18 | 174 | 14 × 22 | 108 8 × 14 | 327 | 12 × 18 | 160 | 12 × 24 | 114 9 × 14 | 291 | 10 × 20 | 169 | 13 × 24 | 105 10 × 14 | 261 | 11 × 20 | 154 | 14 × 24 | 98 8 × 16 | 277 | 12 × 20 | 141 | 16 × 24 | 86 ========+=========+=========+=========+=========+=========

In Table XII is given a list of the different colors of slate used in the Eastern and Middle States, the quarries from which they are obtained, and the cost of slate, labor, etc. per square, pertaining to each variety. The prices in the table are based on the 8 in. × 12 in. or 9 in. × 18 in. sizes, thickness five to 1 inch, and for quantities of not less than 50 squares. The cost of labor, etc. being based on current prices in the aforementioned territory.

Slate ¼ inch thick cost about 20 per cent. more than the five to 1 inch for the material, and about 5 per cent. more for laying and freight.

Slate ⅜ inch thick cost about 45 per cent. more than the five to 1 inch for the material, and about 15 per cent. more for laying and freight.

When copper nails are specified obtain current prices.

TABLE XII

APPROXIMATE COST OF SLATING, PER SQUARE ==================================+========+=========+============ | | Cost of | |Cost of | Laying, | Total Cost, Classification | Slate |Including| Exclusive |F. O. B.| Roofing |of Builder’s |Quarries|Felt, and| Profit | | Freight | ----------------------------------+--------+---------+------------ _Black Slate_ | | | Brownville, Maine | $8.00 | $5.00 | $13.00 Monson, Maine | 7.00 | 5.00 | 12.00 Peach Bottom, Pennsylvania | 5.50 | 4.00 | 9.50 Chapman (Hard Vein), Pennsylvania | 4.50 | 3.50 | 8.00 Bangor, Pennsylvania | 4.50 | 3.50 | 8.00 Lehigh, Pennsylvania | 4.00 | 3.50 | 7.50 Buckingham, Virginia | 3.75 | 4.00 | 7.75 _Red Slate_ | | | Vermont | 12.00 | 4.25 | 16.25 _Green Slate_ | | | Vermont | 5.50 | 4.25 | 9.75 _Purple Slate_ | | | Vermont | 5.00 | 4.25 | 9.25 _Mottled Slate_ | | | Vermont (Purple and Green) | 4.00 | 4.25 | 8.25 ==================================+========+=========+============

=59. Sheet-Metal Roofs.=—In estimating sheet-metal roofs, the hips and valleys are measured extra their entire length by 1 foot in width, to compensate for increased labor and waste of material in cutting and laying. Gutters and conductor pipes, or leaders, are measured by the linear foot, 1 foot extra being added for each angle. All flashings and crestings are measured by the linear foot. No deductions are made for openings (chimneys, skylights, ventilators, or dormer-windows) if they are less than 50 square feet in area; if between 50 and 100 square feet, one-half the area is deducted; if over 100 square feet, the whole opening is deducted. An extra charge is made for labor and waste of material to flash around openings.

=60.= There are two regular sizes of roofing plates, namely, 20 in. × 28 in. and 14 in. × 20 in. The larger size is generally used on common work, owing to the fact that it requires fewer seams on the roof and consequently cheapens the cost of laying. A third size, namely, 10 in. × 20 in., is also supplied, and is used generally for gutters and leader pipes. Sheets 10 in. X 14 in. are sometimes used for laying roofs, as they can be cleated better than the larger sizes. Such small sheets, however, cost more to lay.

Two thicknesses of roofing plates are commonly recognized. One is the IC, or No. 29 gauge, and weighs 8 ounces to the square foot; the other is the IX, or No. 27 gauge, and weighs 10 ounces to the square foot. Sometimes, a still heavier plate is called for, and it is therefore kept in stock by the best manufacturers. This plate is known as IXX, or No. 26 gauge, and is used for especially heavy work.

Formerly, the standard net weight per box of IC, 14" × 20" roofing tin was 112 pounds, or 1 pound per sheet, making 112 sheets to the box; but now this weight is reduced to 108 pounds. The old standard for IX plates was 140 pounds, but very few brands now weigh more than 135 pounds per box. The most reliable manufacturers guarantee the weights for the different boxes of tin, and if the material does not come up to the guaranteed weight, it can be returned. The best sheets in the market today are stamped with the mark of the brand and the designation IC or IX of the thickness.

=61.= Using standing joints, a 14" × 20" sheet of roofing tin will cover about 235 square inches of surface, or one box of such tin will cover about 182 square feet. With a flat, lock seam, a sheet will cover 255 square inches, allowing ⅜ inch all around for joints; or a box will lay 198 square feet. These figures make no allowance for waste.

Two good workmen can put on from 250 to 300 square feet of tin roofing per day of 8 hours; this also includes painting the outside of the tin. Tin roofing will cost from 8 to 10 cents per square foot, depending on the quality of material and workmanship.

=62. Tile Roofs.=—Since =tile roofs= are constructed of so many styles of tile, no general rules of measurement can be given. Every piece of work must be estimated according to the particular kind of tile used and the number of sizes and patterns. Information on all these points is to be found in the catalogs of tile manufacturers.

TABLE XIII

APPROXIMATE COST OF ROOF TILING, PER SQUARE =======================================+=========+=========+========== | | Cost of |Total Cost Classification | | Laying |Exclusive | Cost |Including| of | of Tile | Ashphalt|Builder’s |Delivered| Felt | Profit ---------------------------------------+---------+---------+---------- Shingle tile (rectangular), 6" × 12" | $13.00 | $ 7.50 | $20.50 Shingle tile (rectangular), 8" × 12" | 14.00 | 6.50 | 20.50 Shingle tile (geometric shapes) | 12.00 | 7.00 | 19.00 Conosera (interlocking), 8" × 12" | 14.00 | 5.50 | 19.50 Conosera (interlocking), 10" × 15" | 12.00 | 5.00 | 17.00 Conosera, combination 8" × 12" | | | and 2" × 12" | 16.50 | 8.00 | 24.50 French A (interlocking), size 10" × 15"| 12.00 | 5.00 | 17.00 Spanish, 8" × 12" | 13.00 | 6.50 | 19.50 Old Spanish, semicircular, channels | | | laid alternately, concave and convex | 22.50 | 10.00 | 32.50 Roman, pan and semicircular roll, | | | laid 7½ in. center to center of rolls| 17.00 | 8.00 | 25.00 Greek, pan and semihexagonal cap, | | | laid 7½ in. center to center of caps | 17.00 | 8.00 | 25.00 Promenade for flat roofs, laid on 5 | | | layers of asphalt felt in asphalt | | | pitch | 7.00 | 13.00 | 20.00 =======================================+=========+=========+==========

In Table XIII is given a list of the prevailing styles of roof tiling, the cost of tiling, labor, etc. per square, pertaining to each variety. The prices in the table are based on the natural red color of the clay when burnt; extra prices are asked for glazed-surface finish which can be obtained in different colors. The prices in the table are based on quantities of not less than 30 squares, as less than a minimum carload means increased freight rates. The prices given cover railroad delivery to points in the Eastern and Middle States. Labor, etc. being based on current prices.

The above prices are figured on the tile being laid on wooden sheathing; if laid on book tile or cement add 20 per cent.

If copper nails are used, care must be taken in figuring the number of nails, as well as their length and gauge, for the special forms of tile specified. Fluctuating values of copper make this an item of much importance.

Ridges, hip rolls, barge tile, and finials are charged as extras and due allowance must be made for cutting at valleys and hips.

=63. Gravel Roofs.=—In =gravel roofing=, the cost per square depends on the number of thicknesses of tarred felt and the quantity of pitch used per square. A value of 4 cents per square foot for four thicknesses may be considered an average.

ROOF MENSURATION

=64.= While a knowledge of how to apply the ordinary principles of mensuration is all that is necessary to calculate any roof area, yet the modern house, with its numerous gables and irregular surfaces, introduces complications that render some further explanation of roof measurement desirable. The most common error made in figuring roofs—and one that should be carefully guarded against—is that of using the apparent length of slopes, as shown by the plan or side elevations, instead of the true length, as obtained from the end elevations.

=65.= The area of a plain gable roof, as shown in end and side elevations in Fig. 6, is found by multiplying the length _g j_ by the slope length _b d_, and further multiplying by 2, for both sides. The area of each gable is found by multiplying the width of the gable _a d_ by the altitude _c b_, and dividing by 2.

=66.= In Fig. 7 is shown the plan and elevation of a hip roof, having a deck _z_. The pitch of the roof being the same on each side, the line _c d_ shows the true length of the common rafter _l m_.

In Fig. 8 is shown the method of developing the true lengths of the hips and the true size of one side of the roof. Let _a b c d_ represent the same lines as the corresponding ones in Fig. 7. From the line _a d_, Fig. 8, through _b_ and _c_, draw perpendiculars, as _g h_ and _e f_; lay off from _g_ and _e_ on these lines, the length of the common rafter _c d_, Fig. 7, and draw the lines _a h_ and _d f_, Fig. 8; then the figure _a h f d_ will represent the true shape and size of the side of the roof shown in the elevation in Fig. 7. The area of the triangle _d e f_ is equal to the area of the triangle _a g h_ or a similar triangle _a i h_. Hence, the portion of the roof _a h f d_ is equal in area to the rectangle _a i f e_, the length of which is half the sum of the eave and deck lengths, while its breadth is the length of a common rafter.

=67.= A method of obtaining the lengths of valley rafters, applicable also to hip rafters, is shown in Fig. 9, which is the plan of a hip-and-gable roof. To ascertain the length of the valley rafter _a b_, draw the line _a c_ perpendicular to _a b_ and equal in length to the altitude of the gable; then draw the line _c b_, which will represent the true length of the valley rafter _a b_.

=68.= As an example of roof mensuration, the number of square feet of surface on the roof shown in Fig. 10 will be calculated.

The area of the triangular portion _a c b_ is equal to the slope length of _d c_ (found by laying off _c′ c_ equal to the height of the ridge above the eaves and drawing _c′ d_) multiplied by the length of the eaves line _a b_ and divided by 2. Multiplying the dimensions 13.5 feet and 23 feet, respectively, and dividing by 2, the area is found to be 155.3 square feet.

The area of the trapezoid _g f i h_ is half the sum of _f i_ and _g h_ (shown in their true length on the plan) multiplied by the true length of _h i_. The latter is found by marking the height of the gable _i i′_ on the ridge line, and drawing the line _i′ h_, which measures 10.6 feet. Performing these operations, there results

5 + 14 ------ × 10.6 = 100.7 square feet 2

for each side, or 201.4 square feet for both. As each of the side gables is the same size, the area of the two roofs is 201.4 × 2 = 402.8 square feet.

The area of the polygon _q p n k_ is equal to the triangle _q p w_ minus the triangle _k n w_, the area covered by the intersecting gable roof. The former is equal to the triangle _a c b_, the area of which is 155.3 square feet. The area of _k n w_ is equal to half of _n w_, or 6.5 feet, multiplied by the true length of _k s_ or the altitude of the triangle; the latter is obtained by laying off _k k′_ equal to the height of the gable, 5.5 feet, at right angles to _k s_, and drawing _s k′_, which is the required altitude and which measures almost 7.4 feet. Then _k n w_ = 6.5 × 7.4 = 48.1 square feet; whence _q p n k_ equals 155.3 - 48.1 = 107.2 square feet.

The area of _a p q c_ is

_a p_ + _q c_ ------------- 2

multiplied by the true slope length of _t v_, or _t v′_, which measures 15.2 feet. Substituting dimensions, the area is found to be

6 + 24 ------ × 15.2 = 228 square feet. 2

From this deduct the area of _y z u_, which is the portion covered by the intersecting gable roof. The true length of _t u_ along the slope is _t u′_, measuring 12 feet; hence, the area of _y z u_ is

14 × 12 ------- = 84 square feet. 2

The net area of _a p q c_ is therefore 228 - 84 = 144 square feet; _b c q w_ being equal to _a p q c_, its area is the same, making the area of both sides 288 square feet.

The area of _k n m l_ is

_m n_ + _l k_ -------------- × _m l′_, 2

the slope length of _m l_. Substituting dimensions, the area is

11 + 16 ------- × 8.5 = 114.8 square feet. 2

As _k l x w_ is equal to _k n m l_, the area of both is 229.6 square feet.

Adding the partial areas thus obtained, the sum is 155.3 + 402.8 + 107.2 + 288 + 229.6 = 1,182.9 square feet, or approximately 11.9 squares.

PLASTERING

=69. Plastering= on plain surfaces, such as walls and ceilings, is always measured by the square yard. In determining the cost of plastering walls and ceilings, measure the surface actually plastered, making no deduction for grounds or for openings less than 7 superficial yards. For surfaces of domes or groined ceilings, beams, coves, paneling, etc., a unit price is fixed by the linear or the superficial foot, according to the character and disposition of the work. Round corners and arrises should be measured by the linear foot.

On interior work, increase the price 5 per cent. for each 12 feet above the floor after the first. For outside work, add 1 per cent. for each foot above the lower 20 feet. All repairing and patching should be done at agreed prices.

=70. Stucco Work.=—In estimating =stucco work=, cornices composed of plain members and panel work are measured by the square foot. Enriched cornices with carved moldings are measured by the linear foot. When moldings are less than 12 inches in circumference, measurement is taken by the linear foot; when over 12 inches, superficial measurement is used. For internal angles or miters, add 1 foot to the length of cornice, and for exterior angles add 2 feet to the length. Sections of cornice less than 12 inches measure as 12 inches. Add one-half for raking cornices.

For cornices or moldings abutted against a wall or plain surface, add 1 foot to the length of cornice; if against the soffit of stairs or other inclined or covered surface, add 2 feet to the length of cornice. Octagonal, hexagonal, and similar cornices, less than 10 feet in single stretches, take one and one-half times the length.

For circular or elliptical work, charge double price; for domes and groins, three prices. Enrichments of all kinds should be estimated at an agreed price.

=71. Cost of Plastering.=—The following analysis of the cost of plastering for 100 square yards, for both three-coat and two-coat work, will be of assistance in making estimates. These costs are exclusive of the lathing, which will be taken up later.

COST OF 100 SQUARE YARDS OF THREE-COAT PLASTERING

_Scratch Coat_ 6 bushels of lime, at 25 cents per bushel $ 1.50 9 pounds of hair, at 4 cents per pound .36 ¾ cubic yard of sand, at $1.50 per cubic yard 1.13 5 hours, plasterer’s time, at 50 cents per hour 2.50 5 hours, laborer’s time, at 25 cents per hour 1.25 ------- Total $ 6.74

_Brown Coat_ 6 bushels of lime, at 25 cents per bushel $ 1.50 3 pounds of hair, at 4 cents per pound .12 1 cubic yard of sand, at $1.50 per cubic yard 1.50 13 hours, plasterer’s time, at 50 cents per hour 6.50 6½ hours, laborer’s time, at 25 cents per hour 1.63 ------ Total $11.25

_Finishing Coat_ 3½ bushels of finishing lime, at 35 cents per bushel $ 1.23 ½ barrel of plaster of Paris, at $1.75 per barrel .88 ⅜ bushel of white sand, at 27 cents per bushel .10 18 hours, plasterer’s time, at 50 cents per hour 9.00 4½ hours, laborer’s time, at 25 cents per hour 1.13 ------ Total $12.34

The total cost of 100 square yards of three-coat plaster, then, is $30.33, or about 31 cents per yard.

COST OF 100 SQUARE YARDS OF TWO-COAT PLASTERING

_Brown Coat_ 8 bushels of lime, at 25 cents per bushel $ 2.00 16 pounds of hair, at 4 cents per pound .64 1¼ cubic yards of sand, at $1.50 per cubic yard 1.88 8 hours, plasterer’s time, at 50 cents per hour 4.00 8 hours, laborer’s time, at 25 cents per hour 2.00 ------ Total $10.52

_Finishing Coat_ Same as given for three-coat work $12.34

The total cost of 100 square yards of two-coat plaster is therefore $22.86, or about 23 cents per square yard.

LATHING

=72. Lathing= is measured by the superficial, or square, yard, no openings under 7 superficial yards being deducted.