Back Priming Cedar Siding

Where is the trapped moisture coming from.

Back priming cedar siding. Prime the cedar before you paint it. When back priming be sure to prime the ends of each piece after it has been cut to fit since end grain will absorb the most moisture. Back priming natural wood siding helps control rotting mold build up cupping and movement in the wood ultimately giving your siding and your stain finish more longevity. This is called extractive bleeding a naturally occurring process that does not affect western red cedar s properties.

Regardless of vapor barriers they don t help the siding itself. Importance of back priming when installing wood siding. What that means is that you can put primer on the cedar siding but brown stains will come through. The only way to block the tannins in the cedar siding is to use an oil primer.

Back priming is the best way to treat any exterior wood. You have to use oil primers on cedar siding. A primer with a paint top coat will have a significantly longer service life than will a single coat of paint or even a solid stain. Back priming helps prevent paint from peeling by reducing the amount of water vapor that passes through the wood.

Although intended primarily for restoring horizontal wood surfaces such as decks these products generally work almost as well on vertical surfaces. Prime all sides and end grains or cuts before installation. Uncoated weathered western red cedar siding or trim can often be restored to its original color by applying commercial products called cleaners brighteners or restorers. These are tannins from cedar wood leaking through a water based primer.

Backpriming prevents rotting by sealing the rear side of the wood that is exposed to all the moisture coming out of vapor barriers. Priming western red cedar helps the wood s natural properties stay put. It is strongly recommended that you go with the two coat system for protecting your cedar siding. Back priming consists of applying a coat of primer to the reverse side and edges of boards before installing.

All siding takes on seasonal moisture from sources as diverse as direct rain wicking and vapor diffusion through the wall assembly.