DATA FOR ESTIMATING SHINGLES
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| 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.