I am having a paint failure on a newly painted house: East face, older cedar siding primed with oil primer and 2 coats of acrylic latex top coat, hand brushed. The paint is blistering, and began to fail within one week of application, and it only occurred on the East face of the building.

The house is not under a great deal of heat load, being somewhat shaded and located in Seattle. The building sat drying in late summer sun for a good period. Some of the siding is flat-grain, rather than quarter-sawn material, and these boards are more apt to be blistering. The roof is vented with a continuous ridge vent, and soffit vents below. The failing wall is on a gabled side and therefore has little interaction with the small attic space.

I want to try siding wedges beneath the clapboards to encourage air passage behind the siding. I believe I saw them somewhere in Fine Homebuilding, but my research comes up blank for a source of product. Does anyone know who builds a siding wedge? Any opinions on their performance? Any htoughts are greatly appreciated. Gleno

PS. Appologies for posting in the wrong place. GM