Chapter VII: Introduction (2)

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3. Office buildings of fairly ornamental type, well
broken up with pilasters, projecting courses, etc.,
with pressed-brick facing.

4. Highly ornamental brick buildings, molded cornices,
pilasters, raised quoins, sunk molded panels, and
numerous flat and segmental arches.

TABLE IV

LABOR PRICES PER THOUSAND BRICK FOR
FOUR CLASSES OF BRICK BUILDINGS

=================+=========+=========+========+=========
Part of Building | Class 1 | Class 2 | Class 3| Class 4
-----------------+---------+---------+--------+---------
Basement | $ 7.50 | $ 7.50 | $ 8.50 | $ 9.50
First floor | 8.00 | 9.00 | 10.50 | 13.50
Second floor | 8.50 | 10.00 | 11.00 | 14.00
Third floor | 9.00 | 10.50 | 11.50 | 14.50
Fourth floor | 9.50 | 11.00 | 12.00 | 15.00
Fifth floor | 10.00 | 11.50 | 12.50 | 15.50
Sixth floor | 11.00 | 12.00 | 13.00 | 16.00
=================+=========+=========+========+=========

The prices in the table include the cost of mortar. If the cost of brick at building is added, the result will be the total cost of brickwork exclusive of scaffolding. The average price of total brick labor in buildings of class 1 is $8.50; of class 2, $9.50; of class 3, $11.50; and of class 4, $14.

=37.= The following miscellaneous brick prices, including labor and mortar, but not brick, are from the same source as the prices given in the preceding article, and are based on the same condition, the prices being in bricks per thousand:

For heavy basement walls and similar masses
of brickwork $ 7.00
For 18-inch brick walls not over two or three
stories high, in hard brick with struck joints 8.00
Same as above, but for 13-inch walls 9.00
For 18-inch brick walls, as above, but faced
on one side with pressed brick 12.00
For 18-inch brick walls, as above, but faced on
both sides with pressed brick 16.50
For 13-inch brick walls, as above, but faced
one side with pressed brick 14.00
For 13-inch brick walls, as above, but faced
both sides with pressed brick 14.00
Add to above, if of English or Flemish
bond, on entire cost of wall .50
If work is broken up into light piers, requiring
a lot of plumbing, add to cost of wall as above 1.50
If a large number of segmental arches must
be turned, add to total cost of wall 1.00

In addition to the preceding schedule two useful rules to remember are: For pressed-brick segmental arches, add for labor 1½ times the cost of bricks; for pressed-brick arches requiring radial brick, add for labor twice the cost of straight, pressed brick. As radial brick are shipped to the building in barrels and have to be unpacked and laid out on the full-sized diagram on the floor, it will be found that the rate given is not excessive.

For brick vault arches, the cost of labor, exclusive of mortar, will be about $5 per thousand brick. If pointed underneath, 7 cents per square foot will have to be added. If the centers are left in place until the mortar has set, it will be necessary to rake out the joints and wet them before pointing. This will cost about 10 cents per square foot.

TERRA-COTTA WORK

=38. Terra-Cotta Floor Arches.=—The cost of =terra-cotta floor arches= varies somewhat with the span and with the difficulties encountered in putting up and removing the centering. If the building consists of a number of stories, the centering that is used on one floor may be reused on a floor several stories higher up, in this way decreasing the outlay for centerings. For ordinary spans, the following analysis of the cost of a 12-inch arch, exclusive of the cost of the terra cotta itself, will be found quite accurate, provided the centering is put up by experienced laborers. The price given is per square foot of arch.

CENTS
Centering 3
Hoisting and laying 3½
Mortar ½
-----
Total 7

This price is for work showing a flat ceiling. If the ceiling is much broken up by girders, the price, exclusive of the terra cotta itself, will be about 8 cents per square foot.

As a price per square foot, including the cost of terra cotta, setting, and mortar, the following figures may be taken. These, however, do not include the cost of plastering, or of any concrete fill above the terra cotta.

CENTS
10-inch arches 23
12-inch arches 25
15-inch arches 29

=39. Terra-Cotta Partitions.=—In office buildings, =terra-cotta partitions= are usually erected on top of a floor in order to divide the space into such rooms as will suit the tenants. This work is generally done after the building is otherwise completed. An analysis of the cost of such partitions is given in Table V.

TABLE V

COST OF TERRA-COTTA PARTITIONS
=========+===============+=============+==============
Thickness|Cost of Setting|Cost of Terra|Total Cost per
Inches | per Square | Cotta per | Square Foot
|Foot, Including| Square Foot | Cents
| Mortar | Cents |
| Cents | |
---------+---------------+-------------+--------------
3 | 5 | 9 | 14
4 | 5 | 10 | 15
6 | 6 | 12 | 18
10 | 8 | 16 | 24
=========+===============+=============+==============

The cost of placing 8-inch, terra-cotta backing to brickwork is 6 cents per square foot.

TILING

=40.= Although not always of a brick or terra-cotta nature, it will be found more convenient to consider all =tiling= together and at the same time that the cost of brickwork is taken up.

Only very general figures can be given on the cost of tiling, as this cost depends considerably on the design to be carried out. The cost per square foot of various styles of tile laid in place is as follows:

Moravian tile floors $1.50
Interlocking, rubber tile floors 1.50
Columbia marble tile, 12" × 12", with colored
border, tile laid straight on floor .50
Columbia marble tile, 12" × 12", with colored
border, tile laid diagonally on floor .60
Italian marble tile, 12" × 12", with colored
border, tile laid straight on floor .70
Italian marble tile, 12" × 12", with colored
border, tile laid diagonally on floor .80
Terrazzo and marble mosaic border .38 to .40
Common, white tile in vertical locations, as
lining for elevator shafts, etc. .40
Marble mosaic ceiling work 3.00
Marble and glass mosaic ceiling work 8.00
2-inch book tile (laying only) .04
3-inch book tile (laying only) .04
Shoe tile (laying only) .06

MACKITE

=41. Mackite= is a fireproofing material used for partitions in very much the same way as terra cotta. As this material is put in place by bricklayers, its cost will be taken up here.

Where there are many openings, two bricklayers and one laborer can set 240 square feet of mackite in 8 hours; in a straight wall, without openings, these same men can set about 400 square feet. The market price for 2" × 12" × 30" blocks is 6 cents per square foot; for blocks 3 inches thick, it is 8 cents per square foot. The average price for both material and labor for 2-inch mackite is 10 cents per square foot; for 3-inch material it is about 12 cents per square foot.

CARPENTRY

=42. Carpentry= should include general framing, roofs, floor joists, partitions, sheathing, flooring, furring, and plastering grounds.

=43. Board Measure.=—The rough lumber used in framing is measured by the =board foot=, which means a piece 12 inches square and 1 inch thick. Lumber is always sold on a basis of a thousand feet =board measure=. The customary abbreviation for the latter term is B. M.; that for _thousand_ is M. Thus, 500 feet board measure, costing $27 per thousand, would be written: 500 ft. B. M., at $27 per M.

To obtain the number of board feet in any piece of timber, the length, in inches, should be multiplied by the end area, in square inches, and the result divided by 144. For example, the number of feet B. M. in a floor joist 20 feet long, 3 inches thick, and 10 inches deep is 240 inches (=20 feet × 12) multiplied by 30 square inches (the end area) divided by 144, or 50.

The following rule is used by most contractors and lumber dealers: _Multiply the length in feet by the thickness and width in inches, and divide the product by 12._ Thus, a scantling 26 feet long, 2 inches thick, and 6 inches wide contains

26 × 2 × 6
---------- = 26 feet B. M.
12

This rule, expressed in a slightly different manner, is more convenient for mental computation: _Divide the product of the width and thickness in inches by 12, and multiply the quotient by the length in feet._ Thus, a 2" × 10" plank, 18 feet long, contains

2 × 10
------- = 30 feet B. M.
12 × 18

=44. Prices of Lumber.=—Owing to the continual variation in the prices and grades of lumber, it is impossible to give prices here that will not vary from day to day. The architect before starting to estimate should first be sure that he has the latest lumber prices obtainable. These prices can always be secured from the local lumber dealer.

=45. Studs.=—To calculate the number of =studs=—set on 16-inch centers—the following rule may be used: _From the length of the partition, in feet, deduct one-fourth, and to this result add 1. Count the number of returns, or corners, on the plan, where double studding is required, and add 2 studs for each such return._ (The reason for adding 1 is to include the stud at the end, which would otherwise be omitted.) The sills, plates, and double studs must be measured separately.

For example, the number of studs required for partitions only, shown on the plan, Fig. 4, is computed in the following manner.

30 ft. 6 in.
10 ft. 6 in.
9 ft. 6 in.
5 ft. 0 in.
4 ft. 6 in.
------------
60 ft. 0 in.

Deducting one-quarter from 60 feet,
the remainder is 45 feet; adding
1 stud, the result is 46 feet. As
there are 4 returns, with 2 studs
for each, as shown at _a a_, the
total number is
46 + (4 × 2) = 54 studs.

As a general rule, when (as is customary) the studs are set at _16-inch_ centers, _1 stud for each foot_ in length of partition will be a sufficient allowance to include sills, plates, and double studs. Thus, if the total length of partitions is 75 feet, 75 studs will be sufficient for sills, double studs, etc. If the studs are set at _12-inch_ centers, the number required will be equal to the _number of feet in length of partition plus one-fourth_. Thus, if the length of partitions is 72 feet, 72 + 18, or 90, studs will include those required for sills, plates, etc.

The same rules may be used for calculating the number of joists, rafters, tie-beams, etc.

A good way to estimate bridging is to allow 3 cents apiece, or 6 cents per pair; this will be sufficient to furnish and set a pair made of 2" × 3" spruce or hemlock stuff.

=46. Sheathing.=—To calculate =sheathing= or =rough flooring= (not matched), find the number of feet B. M. required to cover the surface, making no deductions for door or window openings, because what is gained in openings is lost in waste. If the sheathing is laid horizontally, only the actual measurement is necessary; but if it is laid diagonally, add 8 or 10 per cent. to the actual area.

=47. Flooring.=—In estimating =matched flooring=, a square foot of ⅞-inch stuff is considered to be 1 foot B. M. If the flooring is 3 inches or more in width, add one-quarter to the actual number of board feet, to allow for waste of material in forming the tongue and groove; if less than 3 inches wide, add one-third. Flooring of 1⅛-inch finished thickness is considered to be 1¼ inches thick, and for calculating it the following rule may be used: _Increase the surface measure 50 per cent._ (This consists of 25 per cent. for extra thickness over I inch, and 25 per cent. for waste in tonguing and grooving.) To this amount add 5 per cent. for waste in handling and fitting.

In figuring the area of floors, openings for stairs, fireplaces, etc. should be deducted.

=48. Weather Boarding, or Siding.=—In measuring =weather boarding=, or =siding=, the superficial, or square, foot is usually employed. No deduction should be made for ordinary window or door openings, as these usually balance the waste in cutting and fitting. Careful attention must be given to the allowance for lap. If 6-inch, nominal width (actual width, 5⅝ inches), siding, laid with 1-inch lap, is used, add one-quarter to the actual area of the space to be covered, in order to obtain the number of square feet of siding required. If 4-inch stuff is used, add one-third to the actual area. When, as previously noted, no allowance is made for openings, the corner and baseboards need not be figured separately.

=49. Cornices.=—As a general rule, cornices are measured by the running foot, the molded and plain members being taken separately. A good method of figuring cornices is as follows: _Measure the girth, or outline, and allow 1½ cents for each inch of girth, per linear foot._ This price will pay for material and for setting, the cost of the mill work being estimated at 50 per cent.

=50. Cost per Square Foot.=—For all classes of materials that enter into the general framing and covering of a building, a close estimate may be made by analyzing the cost per square foot of surface; that is, the cost of labor and materials—studs and sheathing in walls, joists and flooring in floors, etc.—required for a definite area should be closely determined, and this cost divided by the area considered, will give the price per square foot. If the corresponding whole area is multiplied by the figure thus obtained, the result will, of course, be the cost of that portion of the work. While the usual custom is to adopt a uniform rate for the various grades of work, a careful analysis will show that roof sheathing, where the roof is much cut up, costs more in place than wall sheathing, owing to its position; also that the studs in walls and partitions cost more than floor joists, as they are lighter and require more handling.

The following example shows how to determine the cost per square foot of flooring and indicates the general method to be pursued in similar cases. The area used in the calculation is a square, or 100 square feet. The cost of labor is estimated at 40 per cent. of that of the materials, as it has been shown by experience that this allowance is a very close approximation to the actual cost of general carpenter work.

COST OF FINISHED FLOOR PER SQUARE
Joists, hemlock, 8 pieces, 3" × 10" × 10',
200 feet B. M., at $27 per M. $ 5.40
Bridging, hemlock, 7 sets, 2" × 3" × 1' 4",
9 feet B. M., at $27 per M. .24
Rough flooring, hemlock, ⅛ inch thick, laid
diagonally, 100 ft. + 25 ft. + 10 ft.,
135 feet B. M., at $25 per M. 3.38
Finished flooring, No. 2, white pine, ⅞ inch
thick, 125 feet B. M., at $45 per M. 5.63
Nails, eightpenny (about) 3 pounds, at $2.50
per 100 pounds .08
Labor, 40 per cent. of cost of materials 5.89
------
Total cost for 100 square feet $20.62

Cost per square foot, $20.62 ÷ 100 = 21 cents.

A similar method may be followed in estimating the cost of interior finish, paneling, doors, etc.

=51. Work of a Carpenter per Day.=—The quantity of material that a workman can put in place in a day is very uncertain, as it depends on the skill of the man and the ease or difficulty of the work, both being somewhat modified by circumstances. The figures given in Table VI, while founded on information gained by many years of experience, are only intended to give an idea of the relative quantities and are not a standard to be adhered to in all cases. The estimates are based on an 8-hour day and wages at $3.20 per day. If the hours or pay are less or greater in various localities than the prices given, the results will be correspondingly diminished or increased.

TABLE VI

=52. Cost of Laying Flooring.=—The figures on flooring given in Table VII will be found useful in calculating as they are based on a square, which, as previously stated, is equal to 100 square feet. The same carpenters’ wages and number of working hours as in the preceding article are used here.

TABLE VII

=53. Miscellaneous Carpentry Items.=—In Table VIII is given the cost of several items of carpentry, such as setting window and door frames, furring brick walls, etc. The prices are based on the same wages and hours as in the two preceding articles.

TABLE VIII

=54. Nails.=—To calculate the quantity of nails required in executing any portion of the work, Table IX, which is based on the use of cut nails, will be found useful.

TABLE IX

QUANTITY OF NAILS REQUIRED FOR VARIOUS PURPOSES
======================================+========+=================
Material | Pounds |Kind of Nails and
|Required| Size in Pennies
--------------------------------------+--------+-----------------
1,000 shingles | 5 | 4
1,000 laths, 4 nails to a lath | 7 | 3, fine
1,000 laths, 6 nails to a lath | 9 | 3, fine
1,000 sq. ft. beveled siding | 18 | 6
1,000 sq. ft. sheathing | 20 | 8
1,000 sq. ft. sheathing | 25 | 10
1,000 sq. ft. flooring, rough | 30 | 8
1,000 sq. ft. flooring, rough | 40 | 10
| |
1,000 sq. ft. studding | 15 | 10
| 5 | 20
| |
1,000 sq. ft. furring, 1" × 2" | 10 | 10
1,000 sq. ft. ⅞" finished flooring | 20 | 8 to 10, finish
1,000 sq. ft. 1⅛" finished flooring | 30 | 10, finish
======================================+========+=================

ROOFING

=55. Kinds of Roof Covering.=—The =roof coverings= most generally used are shingles, slate, tin, tile, and tarred paper and gravel (known as gravel roofing). While there are slight variations in the methods of measuring the different kinds, they are all based on the square of 100 square feet.

=56. Shingles.=—In measuring =shingle roofing=, it is necessary to know the exposed length of a shingle. This is found by deducting 3 inches (the usual cover over the head of the lowest shingle in the four overlapping courses) from the length and dividing the remainder by 3. Thus, in Fig. 5, the distance _b_ that one shingle is overlapped by the third above it is usually made equal to 3 inches, and the remaining length of the lowest shingle may be divided into three equal portions, each equal to _a_. The lowest of these three portions is the part exposed to the weather. Multiplying the length exposed to the weather by the average width of a shingle will give the exposed area. Dividing 14,400, the number of square inches in a square, by the exposed area of 1 shingle, in square inches, will give the number of shingles required to cover 100 square feet of roof. For example, it is required to compute the number of shingles 18 in. × 4 in. needed to cover 100 square feet of roof. With a shingle of this length, the exposure will be

18 - 3
------ = 5 inches;
3

then, the exposed area of 1 shingle is 4 in. × 5 in., or 20 square inches, and 1 square requires 14,400 ÷ 20 = 720 shingles.

An allowance should always be made for waste in estimating the number of shingles required.

Table X is arranged for shingles from 15 to 27 inches in length, 4 and 6 inches in width, and for various lengths of exposure.

=57.= Shingles are classed as _shaved_, or _breasted_, and _sawed shingles_.

=Shaved shingles= have fallen almost into disuse, owing to the difficulty of manufacturing them. These shingles vary from 18 to 30 inches in length, and are about ½ inch thick at the butt and ¹/₁₆ inch at the top.

=Sawed shingles= are usually from 14 to 18 inches long and of various thicknesses. In the case of 18-inch shingles, five shingles, at their butts, will make 2¼ inches; that is, the thickness of one shingle at the butt is 2¼ ÷ 5 = .45, or about ⁷/₁₆ inch. At the top, each shingle is ¹/₁₆ inch thick. With 16-inch shingles, however, five of them make only 2 inches. Therefore, the thickness of a 16-inch shingle at the butt is 2 ÷ 5 = .4, or about ⅜, inch.

TABLE X

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.

Plastering laths are about 1¾ inches wide, ¼ inch thick, and usually 4 feet long, the studding being generally placed 12 or 16 inches on centers, so that the ends of the laths may be nailed to them. The laths are usually set from ¼ to ⅜ inch apart, requiring about 1½, 1⁷/₁₆, or 1⅜ four-foot laths, respectively, to cover 1 square foot.

For a fair grade of work, a man will lay on an average about 15 bundles, or 1,500 laths, per day. The price usually paid for laying laths is 25 cents a bundle.

In the following analysis is given the cost of lathing 100 square yards of surface:

COST OF LATHING 100 SQUARE YARDS

14⁴/₁₀ bundles of laths, at 55 cents per bundle $ 7.92
9 pounds of threepenny nails,
at $3.65 per hundred pounds .33
Putting on 14⁴/₁₀ bundles,
at 25 cents per bundle 3.60
------
Total $11.85

The total cost of lathing 100 square yards is therefore $11.85, or about 12 cents per square yard.

JOINERY

=73. Joinery= includes all the interior and exterior finish put in place after the framing and covering are completed; as, for example, door and window frames, doors, baseboards, paneling, wainscoting, stairs, etc. Most of these materials are worked at the mill and are brought to the building ready to set in place.

=74. Frames.=—In taking off =door= and =window frames=, describe and state sizes. Measure architraves by the running foot, giving width and thickness, whether molded or plain, and state the number of plinth and corner blocks.

=75. Sash.=—For =sash=, state dimensions (giving the width first); thickness of the material, molded or plain; style of check-rail and sill finish; thickness of sash bar; whether plain, single or double-hung; and sizes (giving dimensions in inches) and number of lights. Use standard sizes as much as possible.

=76. Doors.=—In taking off =doors=, describe and state the sizes and thicknesses, whether the framing is stuck-molded, raised-molded, or plain; and number of panels, whether plain or raised. Use stock sizes wherever possible and suitable. For special work, where doors are to be veneered, state thickness of veneer, how cores are to be built, and the kind of wood to be used.

=77. Blinds.=—Describe size and thickness of =blinds=; whether paneled or slatted (fixed or movable), and whether molded or plain.

=78. Baseboard and Beam Casings.=—Measure the =baseboard= and =beam casings= by the running foot, stating width and thickness of stuff, and whether molded or plain. When a shoe is used for the base, so state; also, if a surbase is required, give particulars.

=79. Wainscoting.=—Measure =wainscoting= by the superficial foot. State kind of finish, whether paneled or plain, and style of molding and panels. Wainscoting cap and base, measure by the running foot.

=80. Stairways.=—Often =stairways= are taken by the contractor at so much per step, complete according to specifications. In measuring stairways, take off the amount of rough material in carriage timbers, and the planed lumber in treads, etc. Measure balustrades by the linear foot. Give description of newels. Measure spandrel and stairway paneling the same as wainscoting.

=81. Inside Fixtures.=—_Kitchen dressers_ may be taken at a fixed price complete; or at a fixed rate per square foot; or as dressed lumber, drawers and doors being taken separately. _Wardrobes_, _bookcases_, _mantels_, and _china closets_ should be treated separately, and a fixed price stated.

=82. Porches, Etc.=—_Porches_, _exterior balustrades_, _balconies_, _porte cochèrs_, etc. may be taken at a price per linear foot, or the actual quantity of material may be measured.

JOINERY DATA AND EXAMPLES OF ESTIMATING COSTS

=83. Molding.=—Molded work that goes through the mill is usually charged for by the square inch of section per foot in length. Thus, if the price is 1 cent per square inch of section per foot in length, a molding ⅞ in. × 4¾ in. and 12 feet long will cost 60 cents, because the section in the rough is 1 in. × 5 in., or 5 square inches. Therefore, 1 foot of this molding will cost 5 cents, and 12 feet will cost 60 cents. This method of charging for molding, however, is not altogether satisfactory, because it requires as much time to put a narrow piece of molding through the molding machine as it does a wide piece, and a wide piece, since it will have a larger sectional area, will bring a higher price.

A molding machine operates at different speeds, being run at a slow speed when cutting hard woods and at a high speed when cutting soft woods. A machine will turn out from 900 to 4,800 linear feet of molding of any width per hour, the 900 feet representing the amount of very hard wood run through the machine, and the 4,800 feet the amount of soft wood run through when the machine is speeded up to its full capacity. The average output of a machine, however, is about 3,000 feet per hour.

The cost of the machine with a man to operate it may be considered as 70 cents an hour on an average, the man getting 30 cents per hour and the machine being charged for at the rate of 40 cents per hour. Therefore, according to these figures, the cost of machining per linear foot is only ⁷⁰₃3₀₀₀, or .023 of 1 cent. It will thus be seen that the actual cost of putting molding through the machine, especially in large quantities, does not amount to much.

For this reason, especially in the eastern cities, it is cheaper to buy molding direct from the lumber mill than to buy the rough material and then run it through the mill at its destination. In nearly every instance the saving effected in putting the rough material through the machine at its destination is more than counterbalanced by the extra cost of freight rates due to the extra weight. For the same reason, in the eastern market today planed boards are really as cheap as rough ones, because the planed boards are lighter and thus cost less freight.

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Hardware, estimating, and mill designChapter VII: Introduction (2)

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