Cementatious Shake and Slate

1. Roof deck may be spaced or solid sheathing.

2. Fill in between existing spaced sheathing boards is required as needed to meet nailing zone requirements. IRCC recommends a complete fill in of spaced sheathing.

3. This material may not be applied directly over rigid insulation board.

4. This material may not be used to recover over any other roof..

1. All field felt shall be a minimum 18” wide 30# felt interlayment installed to the desired field exposure, not to exceed a nominal 10” exposure unless otherwise specified by manufacturer. 102” exposure over 10 courses shall be accepted as maximum tolerance.

3. All sheet metal valleys shall have a 36” wide 30# felt underlayment unless otherwise specified by manufacturer.

4. Slopes less than 4/12 require additional underlayment. The IRCC recommends a mineral surfaced cap sheet.

5. Application of cementatious material on slopes under 3/12 should be over an impermeable membrane where the shakes are installed for aesthetic purposes only.

1. Nails shall be EG type, box nails, long enough to penetrate 3/4” into or through the sheathing board.

2. Staples shall be galvanized type, 7/16” crown minimum, long enough to penetrate 3/4” into or through the sheathing board.

3. Shorter fasteners are acceptable for use at overhangs and eaves to minimize penetration of the visible underside.

4. Fasteners shall be located so as to penetrate the underlying cementatious material and be covered by the overlaying material. Two fasteners per tile are required.

1. Starter material should be specified in the manufacturer’s instructions.

2. Starter should be fastened in the same manner as field material.

E. FIELD TILES:

1. No felt shall be exposed between the open keyways.

2. Keyway spacing shall be 5/8” maximum.

3. Keyways in alternate courses shall offset 1 1/2” minimum.

F. VALLEYS:

1. 28 gauge, 24” wide, W type metal valley may be used. The cementatious material should overlap a minimum of 6” on each flange.

G. CHIMNEY FLASHING:

1. May be reused if in serviceable condition.

2. If counter flashing is replaced, it may be fastened to the chimney with concrete nails and sealed with a good exterior caulk.

1. May be reused if they are the proper type and in serviceable condition.

2. Plumbing pipes may be sealed to the flashing with flashing tape, rubber collar, or plastic cement.

3. Painting of flashing to blend with the roofing is desirable but not required.

4. Exposed galvanized fasteners on base flashing is acceptable.

1. Edge metal is required to cover exposed edges of plywood.

2. Painting of edge metal is not required.

3. When flashing against a vertical side wall:

a. New flashings may be installed if feasible. If new flashings are installed on the exterior of the wall, the flashing should be counter flashed with wood or metal sealed to the wall with a good exterior caulk.

b. The old flashings may be reused if they are the proper type and in serviceable condition. The flashings should be lifted and installed with the new shingles.

1. Ridge should be installed with one galvanized nail on each side penetrating into the sheathing at least 3/4”. Exposed nailing is acceptable.

2. Spacing of ridge shingles shall match that of the field or manufacturer’s recommendations, whichever is less.

K. BUILDING DEPARTMENT INSPECTIONS:

1. In-progress inspections should include spot checks of decking, plywood nailing, shingle application, and flashing installation.

2. Final inspections should be done from the ground to avoid damage to the cementatious material.