For optimum performance, the WRCLA recommends that Western Red Cedar is pre-primed or pre-finished prior to job site delivery.
Factory-priming, as the name implies, is performed in an industrial setting where a machine coating process applies a coating to all six sides of each board. The coated boards are then dried prior to shipment to the job sites.
Pre-primed siding and trim boards delivered to a job site should be kept dry and clean prior to installation. All field cuts should be re-sealed with a primer prior to the boards being installed. Top coating should be completed as quickly as possible as most primers are not intended to be exposed to natural weathering for more than 90 days.
Factory–finishing is similar to the above process, however, it allows for the additional application of one or two topcoats of acrylic latex paint, solid stains or natural stains in job lot quantities and in the colors selected by the builder/homeowner.
It is important not to overdrive nails during installation of factory finished siding, as this will damage the surrounding wood and coating. Overdriven nails must be remedied immediately by filling the depression with exterior grade wood putty specifically designed for this purpose. Touch-up any repairs or field cuts, taking care not to smear the top coat.
Properly done, factory priming/finishing provides:
- the application of a uniform coating at the recommended coverage of the primer/stain to all six surfaces of each piece (face, back, edges and ends)
- a controlled environment to permit proper curing of the finish
- the wood with a coating to protect it from exposure to sunlight (UV degradation) and surface contamination by mildew and dirt
- an elimination of lap marks, streaks and shrink lines after installation
- an ability to install products at any time of the year
- a product that often comes with a coating warranty.