Q: Our recently enclosed screen porch has a concrete slab floor that is covered with slate. Dampness seems to be coming up through the floor during rainy days and staining the joints between the slates. Do you have any advice as to how we can correct this?
A: If moisture is actually coming up through the concrete floor, the condition may be pretty difficult to cure. About the only thing that might work is to apply a coat of clear epoxy waterproofing -- a two-part material that is sold for use in waterproofing basement walls. It has an amber cast and will darken the floor slightly, but it should hold back mild seepage. However, it is expensive.
There is one other possibility. You may not have a seepage problem at all. It could be condensation forming on the surface of the cold floor. There is not much you can do to stop this on an open porch, but you can keep the moisture from staining the mortar joints by coating them with clear masonry sealer.
Q: More than two years ago I had my wood shingle house painted with latex paint over previous coats of oil paint. Parts peeled the next summer and were repainted, but last year the peeling started again -- down to the bare wood and the metal gutters. I now realize that changing from oil to latex paint was a mistake, but wonder if it is possible to correct the situation without repainting the entire house?
A: Changing from oil paint to latex was not necessarily a mistake, and probably has nothing to do with your peeling problem. The fact that it is peeling down to the bare metal and wood indicates that it is the old paint that is letting go (and taking the new paint on top with it), not just the new paint.
There are many reasons why this could happen, but one reason could be moisture getting behind the paint and into the wood. Check all calking, putty, and flashing around the outside and replace or repair where it looks defective. Scrape the peeling spots off, then prime these areas with a primer suitable for that particular surface, and repaint with two coats of finish.
Q: In two of my rooms paint was applied over wallpaper by the previous owner. It's hard to tell how many layers of paper there are, but there seems to be just one coat of paint. I have been advised to size the paper and then apply another layer of wallpaper, or to remove the painted wallpaper and then either paint or paper the walls. What do you suggest, and what is the best way to remove the paper?
A: I recommend removing the painted paper -- adding another layer will only postpone the problem and make it worse. I suggest renting a steaming machine to remove the paper. Rub over the paper with the coarset sandpaper you can find (the kind sold for floor-scraping is best). The steam will then penetrate through the scratches to soften the paste and the backing so they can be removed.