Installation Guide

Maximum weather exposure
Shingle 3:12 to 4:12 4:12 and
length roof slope steeper
16" 3 3/4" 5"
18" 4 1/4" 5 1/2"
24" 5 3/4" 7 1/2"
Shake length and exposure
18 " 7 1/2"
24" 10"
Note exception for resawn shakes:
24" x 3/8" shake = 7 1/2"
SPECIFICATION GUIDELINES
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Architect: Bill Latoza, Photo: Bill Latoza
This information has been designed to aid
architects, consultants and builders in
specifying Certi-label shakes and shingles. It
suggests a standardized terminology and style
for ordering in the hope of improving
accuracy. It incorporates a general outline of
the latest application information. Please note,
however, that this is a specification guide only.
The information in this manual is not
intended to supercede local building codes.
Refer to local building codes for more
information.
1. The contractor shall cover all roof surfaces
with (specify one type of the following
product) Certi-Split shakes/Certi-Sawn
shakes/Certigrade shingles bearing the
Cedar Shake & Shingle Bureau’s official
grade marked label.
2. Shakes/shingles for roofs shall be (specify
grade and length).
3. Shakes/shingles for outer courses shall be
(specify grade and length).
4. Shakes/shingles for undercourses shall be
(specify grade and length).
5. Roof shakes/shingles shall be laid with a
weather exposure of (specify in inches).
6. Certi-Split shakes/Certi-Sawn shakes shall
be applied over solid sheathing. A solid
deck is recommended in seismic activity,
hurricane and tornado regions and in
areas where wind-driven snow is
encountered and under pressure
impregnated treated shakes and shingles.
Please note that the only solid sheet
sheathing tested with Certi-label shakes &
shingles is plywood. Check with your local
building official for plywood
thickness/dimensions.
Certi-Split shakes/Certi-Sawn
shakes/Certigrade shingles may also be
applied over spaced sheathing.
7. All open sheathing shall be 1 x 4 or 1 x 6
boards (minimum 1 x 4 for both shakes
and shingles).
General Specification Data
Roof Application-Sheathing Boards
8. All solid sheathing shall be lumber or
structural panels applied according to
specifications of the American Plywood
Association. Please note: the only solid
sheet sheathing tested with shakes and
shingles is plywood. Check with your local
building official for plywood thickness/
dimensions.
9. Contractor shall apply a 36" wide strip of
No. 30 ASTM D226 Type II or No. 30 ASTM
D4869 Type lV roofing felt at the eave line.
An 18" wide strip of No. 30 ASTM D226
Type ll or No. 30 ASTM D4869 Type lV
roofing felt shall be applied over the top
portion of the Certi-label shakes and
extend onto the sheathing. Bottom edge of
felt shall be positioned at a distance above
the butt equal to twice the weather
exposure.
Note: felt interlay between courses is not
necessary when straight-split, or taper-split
shakes are applied in snow-free areas at
weather exposures of less than one-third
the total shake length (3-ply roof). Contact
the CSSB for more information or visit
10. Certi-label shakes/shingles shall be at least
doubled at all eaves.
11. Butts of the Certi-label shakes/shingles in
the first course on roofs shall project 1 1/2"
from the edge of roof eaves to insure
proper spill into gutters and approximately
1" at gable and rake edge.
12. Certigrade shingles shall be spaced apart
not less than 1/4", not more than 3/8".
13. Certi-Split or Certi-Sawn shakes shall be
spaced apart not less than 3/8", not more
than 5/8".
Roofing Felt Interlay
(for shakes only)
Roofing General Application Data
www.cedarbureau.org
14. Premium and Number 1 Grade
Certi-label shakes/shingles shall be applied
with the weather exposures consistent with
the following tables:
15. Chimney flashing shall extend up the
chimney to a height not less than 3", up
the roof slope to a point equal in height to
the flashing on the chimney but never less
than 1 1/2 times the Certi-label
shake/shingle exposure. (All metal
flashings should be painted.)
Manufactured step-flashing:
5" x 7" shingle = 2 1/2" wall, 2 1/2" roof
8" x 12" shakes = 4" wall, 4" roof
16. Apron counter flashing shall extend to
within 1" of the surface of the finished
roof.