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.
General Specification Data
- The contractor shall cover all roof surfaces with Certi-Split® shakes/Certi-Sawn® shakes/Certigrade shingles bearing the Cedar Shake and Shingle Bureau's official grade marked label.
- Shakes/shingles for roofs shall be (specify grade and length).
- Shakes/shingles for outer courses shall be (specify grade and length).
- Shakes/shingles for undercourses shall be (specify grade and length).
- Roof shakes/shingles shall be laid with a weather exposure of (specify in inches).
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Roof Application - Sheathing Boards
- Certi-Split® shakes/Certi-Sawn® shakes/Certigrade shingles shall be applied over spaced sheathing. Solid sheathing is acceptable and may be required in seismic regions or under treated shakes and shingles. In areas where wind-driven snow is common, solid sheathing is recommended under shakes. Please note: the only solid sheet sheathing tested with shakes and shingles is plywood. Check with your local building official for plywood thickness/dimensions.
- All open sheathing shall be 1 x 4 or 1 x 6 boards (minimum 1 x 4 for both shakes and shingles).
- 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.
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Roofing Felt Interlay (for shakes only)
- Contractor shall apply a 36" wide strip of Type 30 minimum roofing felt at the eave line. An 18" strip of Type 30 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 of the total shake length (three-ply roof).
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Roofing General Application Data
- Certi-labeled shakes/shingles shall be at least doubled at all eaves.
- Butts of the Certi-label™ shakes/shingles in the first course on roofs shall project 1 1/2" from the edge of the roof eaves to ensure proper spill into gutters and approximately 1" at gable and rake edge.
- Certigrade shingles shall be spaced apart not less than 1/4", nor more than 3/8".
- Certi-Split® or Certi-Sawn® shakes shall be spaced apart not less than 3/8", nor more than 5/8".
- Premium and Number 1 Grade Certi-label™ shakes/shingles shall be applied with the weather exposures consistent with the following tables:
| Shingle
Length |
3:12 to 4:12
Roof Slope |
4:12 and
Steeper |
| 16" |
3 3/4" |
5" |
| 18" |
4 1/4" |
5 1/2" |
| 24" |
5 3/4" |
7 1/2" |
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| Note exception for resawn shakes:
24" x 3/8" shake= 7 1/2" |
- 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" shake= 4" wall, 4" roof
- Apron counter flashing shall extend to within 1" of the surface of the finished roof.
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