Part 13

=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

QUANTITIES OF MATERIAL PUT IN PLACE PER DAY BY ONE MAN ===================================+===========+==================== | Number of | Class of Material |Feet B. M.,| Remarks | or Number | -----------------------------------+-----------+-------------------- Studding 2" × 4", or 2" × 6" | 400 |Wall or partition. Rafters | 400 | Rafter ridge and bracing | 250 | Plate, 6" × 8", halved at corners | 350 | Floor joists, 2" × 10", or 3" × 12"| 500 | Ceiling joists, 2" × 6" | 450 | Sheathing, unmatched | 500 |Laid horizontally. Sheathing, unmatched | 400 |Laid diagonally. Sheathing, matched | 400 |Laid horizontally. Sheathing, matched | 300 |Laid diagonally. Sheathing, roof | 750 |Plain gable roof. | | | |Much cut up by hips, Sheathing, roof | 300 | valleys, dormers, | | etc. | | Ceiling lined with paper | 200 | | | | |Includes fitting Siding, 4 inches wide | 200 | and setting Siding, 6 inches wide | 300 | corner boards, | | base, trim, and | | scaffolding. | | | |Includes scarfing Posts and beams over cellars | 200-250 | and doweling. | | | |For base and | | wainscot, Plaster grounds, linear feet | 250 | straightened | | in good shape. | | Bridging, number of pairs per hour | 10 |Includes cutting | | and setting. | | False jambs around openings, | 1 | per hour | | ===================================+===========+========================

=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

LABOR COST OF LAYING WOODEN FLOORS, ETC. =========================================+===========+========= | Number of |Cost per Classes of Materials, Etc. |Squares per|Square at |Man per Day|40 Cents |of 8 Hours |per Hour -----------------------------------------+-----------+--------- Rough matched hemlock floor, | 3 | 6 inches wide | | $ 1.07 3-inch spruce floors laid at | 3½ | .91 right angles to the beams | | Yellow pine floor, with struck joints | 1½ | 2.13 Cypress porch floor, finished with | 1 | 3.20 white-lead joints | | ⅞-inch maple floor laid on a plank floor,| 2 | 1.60 with paper between; | | also, struck joints | | Laying straight-oak floor | 1 | 3.20 Scraping oak floors | ⅓ | 9.60 Finishing and waxing oak floors | ⅔ | 4.80 Parquet floor in 2-inch strips of blocks,| ¼ | 12.80 12" × 6" or 16" × 8" | | Scraping parquet floor | ¼ | 12.80 Finishing and waxing parquet floor | ⅔ | to good finish | | 4.80 Sleepers, laying and setting, | | .02 per linear foot | | =========================================+===========+=========

=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

COST OF MISCELLANEOUS ITEMS OF CARPENTRY ===================================+=======+======================= Class of Work | Cost | Remarks -----------------------------------+-------+----------------------- Setting window frames in |$ .45 |Each. wooden buildings | | | |Per square foot; Furring brick walls, 1" × 2" | .02½ | includes labor, strips, 12-inch centers | | material, and nails. | | Furring brick walls, 1" × 2" | .01⅞ |Per square foot. strips, 16-inch centers | | | | Cutting holes and fitting | .05 |Each. plugs in brick walls | | | | Setting window frames in brickwork| .60 |Each; includes nails | | and bracing. | | Setting door frames in brickwork | .60 |Each. | | Setting window frames in stonework | 1.25 |Each, for ordinary work. | | Setting window frames in stonework | 2.00 |Each, for very careful | | work. | | Setting door frames in stonework | 2.00 |Each, for very careful | | work. | | Furnishing and setting trimmer-arch| 2.00 |Each centers | | | | Arch centers, 4-foot span, | 1.50 |Each; includes supports 8-inch reveal | | and wedges. ===================================+=======+=======================

=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