Q. The paint on our 44-year-old house is peeling down to bare wood and we need to repaint. Did the use of latex over oil-based paint cause the problem and, if so, what type of paint would be best to use now? Does the color make a difference in paint longevity? We once had water seepage in the basement, but that has since been corrected. The house is fully insulated, including the walls. How about water running off the roof and behind the clapboards? Is this a problem? Should the clapboards be power-washed before repainting?Should we repaint this year, or is there any advantage in waiting? Mr. and Mrs. Carter V. Findley Columbus, Ohio
A. Latex over oil-based paint did not necessarily contribute to the peeling problem. The fact that bare wood is exposed under the blisters indicates that the original coat or primer is losing its adhesion to the substrate. As additional coats of paint shrink, a significant "pull" is exerted on the oil surface.
The sun's heat intensifies the "pull" by vaporizing the moisture in the wood. Presto: blisters! This is the problem, and not the earlier water in the basement. For added water protection on the interior basement walls, however, apply a couple of coats of Sealwall, or its equal, following the manufacturer's directions explicitly.
The heavy insulation is probably not a contributing cause, either.
As to water running off the roof and behind the clapboards, it is vital to flash and counterflash where rainwater tends to rund from roof to wall or wall to roof. Thus, prevent the water from getting behind the boards. Minimize the moisture contact where and as practical. Thwart any moisture from discharging or remaining on the painted siding.
The permanent solution, alas, is to laboriously remove all the old paint down to the bare wood. Then reprime with a high-quality oil-based undercoater. Follow with a top coat in a finish of your choice in material and color.
Color may have little to do with paint longevity, but paint quality is an important index. Avoid cheap paint.
I don't feel that power-washing is necessary at this time. When you repaint the house the next time around, you may want to reconsider a high-pressure hosing of the siding, if it seems to need it.
As for timing, I suggest you remove the old paint and repaint as soon as possible.
To minimize a recurrence of this sort of peeling problem, use only good-quality paint materials and good workmanship. Then follow and annual touch-up program which involves sanding off any paint blisters and then repriming and repainting these spots.
Such an annual maintenance program will extend the life of a paint job for perhaps two or three years.