Improving the Performance of Painted Wood Siding; Rai Screen, End-Grain Seal, And Back Priming

By Edward Burke, Tony Bonura, Charles Carll, Dennis Connelly, Christopher Hunt, Doug Mall, Arnie Nebelsick, Norm Slavik, Brent Stuart, Alex Wiedenhoeft, R. Sam Williams

Moisture control is a critical means of improving the performance of solid-color stain and paint on wood siding. In this article, recommendations are given for constructing a rain screen, sealing the end grain, and back-priming siding to achieve this goal.

Rain screen construction and back priming inhibit water absorption and bleed from run-down extractives if water gets behind the siding. Inhibiting water absorption improves dimensional stability of siding, thus improving finish performance. Sealing the end grain with primer decreases paint peeling and bleeding of diffuse extractives near the end of boards.

These techniques should be used in combination with structure designs having adequate roof overhangs, ground clearance to bottom course of siding, roof-edge flashing, gutters, and downspouts.