Installation Guide
Insulated Concrete Forms (I.C.F.)
These systems have no wood component and the foam has no nail holding capacity. As a result, Insulated
Concrete Forms require framing of a minimum of 1¼” thick spaced 16 inches on center on the outside of the
foam. Note these will need to be securely fastened to the concrete.
Rigid Foam Sheathing
Rigid foam sheathing has an insulation value superior to that of traditional lumber and plywood sheathings.
However, it has no nail holding power and using rigid foam sheathing as a nailing base for cedar siding is
not recommended. Follow the nailing recommendations given in this publication as to nail type, positioning,
penetration and spacing.
Foam sheathing panels vary in moisture permeability but are generally considered good moisture barriers. They
should be used with a continuous lm vapor retarder on the inside wall under the interior nish. Rigid foam
sheathing can cause moisture to accumulate on the back of siding and cause staining, buckling and damage
to nish coats. As a result, it is recommended that furring strips are used to create an air space between the
sheathing and siding (follow the rainscreen construction method).
Other recommendations that should be followed to minimize potential problems:
• Thick, narrow siding is more stable than thinner, wider patterns and better able to resist dimensional changes.
• Use kiln-dried siding over rigid foam sheathing. This is the most stable cedar siding.
• Proper prenishing is essential.
• Use light color nish coats to maximize heat reection and reduce dimensional movement.
• In all cases it is strongly recommended that gas permeable house wrap, such as DuPont™ Tyvek®
DrainWrap™, be applied over the foam sheathing.
BEFORE YOU START
WESTERN RED CEDAR
SIDING
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