Installation Guide

Table 4: COVERAGE ESTIMATOR
Width
Factor for Factor for
Nominal Exposed Lineal Board
Pattern Width Dressed Face Feet
1
Feet
2
43¹₂ 2¹₂ 4.8 1.60
Bevel & 6 5¹₂ 4¹₂ 2.67 1.33
Bungalow 8 7¹⁄₄ 6¹⁄₄ 1.92 1.28
10 9¹⁄₄ 8¹⁄₄ 1.45 1.21
43¹₂ 3 4.0 1.33
Dolly 6 5¹₂ 5 2.4 1.2
Varden 8 7¹⁄₄ 6³⁄₄ 1.78 1.19
10 9¹⁄₄ 8³⁄₄ 1.37 1.14
12 11¹⁄₄ 10 ³⁄₄ 1.12 1.12
43³⁄₈ 3¹⁄₈ 3.84 1.28
Drop,T&G and 6 5³⁄₈ 5¹⁄₈ 2.34 1.17
Channel Rustic 8 7¹⁄₈ 6⁷⁄₈ 1.75 1.16
10 9¹⁄₈ 8 ⁷⁄₈ 1.35 1.13
65⁷₁₆ 4¹⁵₁₆ 2.43 2.43
Log Cabin 8 7¹⁄₈ 6⁵₈ 1.81 2.42
10 9¹⁄₈ 8⁵₈ 1.39 2.32
21¹₂
43¹₂
Boards 6 5¹₂
87¹⁄₄
10 9¹⁄₄
11
Coverage Calculations
Siding is usually sold either by the
lineal (running) foot or by the board
foot.
To simplify cost and coverage
estimations, select the appropriate
factor from Table 4 according to
how the siding is priced. The factors
provided in Table 4 can be used to
calculate the amount of siding
required either in lineal feet or in
board feet.
In either case, the square footage
of the area to be covered is calcu-
lated first, then multiplied by the
appropriate factor.
Procedure:
A) Calculate the square footage
in walls:
length x width = sq. ft.
B) Calculate and then subtract the
square footage of openings.
Now add 10% for trim and
waste.
C) Multiply the result by either the
factor for lineal feet or
the factor
for board feet.
D) Multiply the total footage
required by price.
Additional Information
Technical information on Western
lumber products manufactured by
WWPA mills is available through the
Association’s Online Technical
Guide at www.wwpa.org. Free
registration is required. The Online
Guide features sections on lumber
grades, design values, specifica-
tions and properties of Western
lumber.
For a full description of technical
publications available for purchase
or download, go to the Online
Literature Store on the WWPA web
site.
Checklist for High Performance, Long-Lasting,
Beautiful Natural Wood Siding
■ Select climate- and design-appropriate patterns with surface textures
appropriate for the desired finish.
■ Specify species and grade compatible with budget.
■ Allow siding to acclimate at job site.
■ Prefinish all surfaces (sides, edges, ends) with:
• water repellent that contains a mildewcide (and is compatible with the
final finish), and/or*
• stain or bleaching oil, if one of these is to be the final finish, or
• primer, if paint is to be the final finish.
■ Use an appropriate sheathing wrap. Make certain it is dry before
applying siding.
■ Allow for drainage between the sheathing wrap and the siding.
■ Apply siding, using the right nails, in accordance with correct nailing pro-
cedures. Incorporate appropriate construction practices at corners.
■ Provide additional coats of protective finish as required.
*While water repellents are not recommended for use under most stains, they can be used to
coat the backside of siding when stain or bleaching oil will be applied to face, edges and
ends.
The exposed face width will vary depending on
size selected and on how the boards-and-battens
or boards-on-boards are applied. Minimum over-
lap is ¹₂". Determine the exposed face, then refer
to footnotes to calculate factor.
1
Lineal Foot Factor is derived by dividing 12" by the exposed face width.
2
Board Foot Factor is derived by dividing the nominal width by the exposed face width and is based on
nominal 1" stock, except log cabin. Log cabin is based on 2" thickness. For nominal 1¹₂" log cabin,
multiply by .75.
Note: Factors do not include any allowance for trim or waste and do not apply to diagonal installations. A
10% allowance for trim and waste (25-30% for diagonal installations) should be added to the square footage
required before the factors are used. Refer to Procedure at left.