Cracking of Stained Rough-Sawn Siding
 

Description:
Thin, long relatively straight cracks running in a singular direction on a previously stained, wood surface.

Possible Cause:
The most common surface to show this failure is rough sawn plywood, shakes, and shingles, that have been stained with a semi-transparent or solid color alkyd stain. The main reason for “Cracking,” is moisture content. With stain, the coating usually does not peel or flake. Instead, the wood is open for moisture intrusion from outside weather conditions, leading to delamination and deterioration of the wood.

The wood is highly textured, allowing water to remain on the total surface for extended time periods. These woods are designed for staining and since cracking is inevitable, the life of the coating is shortened. Pigmented stains penetrate the porous wood surface, allowing very little of the stain to remain on the surface. Subsequently, as the wood cracks, the applied stain also cracks.

Solution:
Using detergent and water, scrub siding to remove old oxidized stain film, dirt and other contaminants. Flush with clean water and allow to dry thoroughly. Fill large holes found in plywood grooves with colored caulk to prevent further water intrusion.

Recommended System:
Topcoat
2 coats FLEX BON #490 Series Acrylic Solid Wood Stain "STAIN COAT"