Q. Is there a paint which can be applied to inside walls, plaster or paper, which will serve as a vapor barrier to keep moisture from entering new blown-in wall insulation? Would it also be effective as a vapor barrier for batt-type insulation in a new house? Four years ago we had insulation blown into the walls of an old house. Now some of the paint is peeling. What can be done to dry out the insulation if it is damp and thus prevent more trouble? Marvin E. Thornburg Washington C.H., Ohio
A. There are paints on the market shelf which are designed as vapor barriers but are usually difficult to obtain in very small quantities. However, many "dense" coating systems can provide a minimum of vapor transmission, such as gloss epoxies, gloss urethanes, and some chlorinated rubber systems that are used to paint swimming pools.
ACtually, a high-gloss, oil-base enamel would probably prevent most vapor transmission.
If blown-in wall insulation has become damp, remove the plugs which pierce the wall and let the insulation aerate.
We reckon that the above answer would apply to both batt-type insulation as well as that which is blown in through the walls.