LESSON 3
ANSWERS TO SELF TEST
Plywood has approximately equal strength in both length and width, has greater resistance to checking and
1.
splitting, is less affected by changes in moisture content, provides more bracing effect, and requires less labor
in installation (para 3-lb).
"One-in-three" spacing means that the space left between sheathing boards is twice the width of the boards. It
2.
is used when corrugated sheet metal or other strong, large-panel material is used for roof covering (para 3-
3c).
Corrugated sheet metal and prepared (roll) roofing (para 3-4).
3.
When using corrugated sheet metal roofing, the roof slope must not be less than four inches per foot of run.
4.
Therefore: 10 x 4 = 40 inches, or 3' - 4" total rise (para 3-5a)
Rafter line length = 11'- 4"
5.
Overhang
= 2'
13' - 4" = 13 1/3 feet
60 x 13 1/3 x 2 (no. of slopes) = 1600 sq ft
1600 80 = 20 rolls required.
Roof slopes of less than 1 inch per foot require multilayer built-up roofing (para 3-5b).
6.
A flashing is installed, made up of either two layers of roll roofing, or a strip of sheet metal (para 3-6).
7.
Where rafters have no overhang, the first piece of sheathing is placed on the rafters so that it hangs over the
8.
rafters 3 to 4 inches (para 3-8b)
When corrugated sheet metal is used, it should overhang the sheathing from 1 to 2 inches on the gable ends as
9.
well as on the eaves, to provide added protection to the walls (para 3-8c).
Vertical sheathing helps to support the roof load on the top plate, while horizontal sheathing does not (para 3-
10.
9b).
Drop and shiplap siding have a rabbeted edge to give the proper lap. The lap must be measured each time in
11.
applying bevel siding, which requires much time (para 3-9c).
Asphaltic felt or tar paper used behind sheet iron will cause the metal to rust (para 3-9d).
12.
The interior door frame is constructed like the exterior door frame except that no casing is used on inside door
13.
frames (para 3-10c).
The hinges are fastened to the battens of the door and to the hinge blocks on the door casing or post (para 3-
14.
10d).
3A-1
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