After cedar has achieved equilibrium moisture content and before it is installed, a coating on all surfaces is recommended. The type of coating will vary with final finish selected. The coating protects the wood from water penetration, helps prevent staining caused by mildew and extractives and can increase the service life of top coats.
Figure 1. Siding stacked with vertically aligned stickers.
The following coatings have proven themselves in field testing (see table below).
Check with your paint dealer to make sure that the prefinish coat you select is compatible with the intended finish coat. For example, clear water repellants should not be used where the intended finish is a bleaching oil.
Table: Recommended Priming Procedures for Cedar Siding.
|Type of Finish Coat
|Recommended Priming Coat
|Natural and semi-transparent stains
|Coat all surfaces with the stain
|Solid color stains and paints
|Coat all surfaces with an alkyd oil stain-blocking primer. Alternatively, use a clear water repellant on back of siding and the primer on face and edges
|Prime all surfaces with a coat of the bleaching oil