Back Prime Siding

Back priming helps prevent paint from peeling by reducing the amount of water vapor that passes through the wood.

Back prime siding.

Therefore do not prime the back side of the siding or trim. Not only does back priming prevent rot it prevents bowing cupping. It occurs either when heated or air conditioned air from the house radiates out and meets the cold or hot outside air. Back priming consists of applying a coat of primer to the reverse side and edges of boards before installing.

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

First of all lets explain what is back priming. While back priming has proven to be useful to control tannin staining with some types of solid wood siding trim and some composite sidings lp smartside products are not intended to be back primed. According to rick crotts my local james hardie representative it s not necessary to back prime any of the company s fiber cement siding products. He says that when panels are primed in the factory some primer ends up on the back of the boards as they pass over the rollers but this isn t a half hearted attempt at priming the backs.

For best results fresh siding should be pre primed on all six sides with a stain blocking primer and top coated with 100 percent acrylic latex paint. Importance of back priming when installing wood siding. Dont know what type siding your using but hardie is already primed i think it 39 s primed on both sides i have installed it on my house even if not dont let the exposed side stay un painted too long or you will have to prime it use good paint and it will last a long time even cheap paint will do well on hardie. Types of paint to use.

Alkyd oil primers are recommended but one may choose a high quality latex primer as long as it contains stain blockers. The back side is better left unpainted.