When finishing a basement, properly prepare exterior walls

Q. Our house is about 60 years old with a cinder block foundation. We are beginning the process of finishing our basement and need to address some water issues. Our basement is very dry; the previous owner said it had not flooded in the 25 years she lived here, and we've had only minor issues with water in extremely wet weather. The walls in the basement have been painted by previous owners, probably with a waterproofing paint, but I really don't know. In a number of areas the paint has chipped off or been damaged by lime buildup, leaving areas of cinder block exposed.

We have not had any water coming in where the old paint is chipped or missing, however, and I was wondering if that would be an indication that there is not likely to be significant water buildup. We have experienced some water seepage when days and weeks of rain have saturated the ground. The seepage occurs in a few isolated locations, and the water comes up from where the wall and floor meet. The seepage is minor, never causing flooding, but resulting in a 6- to 10-foot line of wetness along the wall that is 4 to 6 inches wide.

I would like to know if you think that an application of a small amount of Drylok cement at the joint where the wall meets the floor would be detrimental and cause the type of mold issues you warn against. What might you suggest to address the water issue before we finish the basement?

A. You are right. It does not seem that there's any buildup of water within the blocks. I would not recommend applying any waterproofing at the joint of the walls and floor because it would cause water to accumulate within the blocks' cores. As it is now, when you experience the mild-leakage episodes, that floor/wall joint is the relief valve that prevents a potentially worse problem.

The lime buildup you refer to is efflorescence from the wall's moisture evaporating, which leaves behind salts that have dissolved from the masonry. I suggest that you check the grade around the house and correct any flat or negative grades so water does not percolate against the foundation. To ensure that no damage will occur to whatever finish you apply to the basement walls, use a pressure-treated 2-by-4-inch bottom plate for any partition you plan to build and keep all finish material (drywall or paneling) at least half an inch off the floor.

You should not use any wall-to-wall padding or carpeting on the floor, opting instead to use scatter rugs or to stain the concrete (paint is likely to peel). Another option is to have a flooring contractor install tiles that can withstand the existing conditions. But, if you choose ceramic or quarry tiles, make sure that they are installed before the walls go up so that the pressure-treated wall plate sits on them, and that they aren't installed tightly to the wall plate, where they would create a dam. Under the circumstances, I would insulate the walls only from the top of the cinder blocks down to 2 feet below grade in order to prevent any potential frost damage and to allow any moisture to dry through the walls. For that purpose, drywall or board paneling would be better than prefinished plywood paneling with a plasticized finish.

My tan bathtub has white streaks along one side and the bottom. The cleaning lady did not remember what agent she used. Although the tub has drip-like white streaks, the surface is smooth like the rest of it. I never knew this could occur without eroding the surface above. Do you have any clue as to what she could have used? Is the only way to have a uniform tub to coat the rest with whatever she used? (If we can deduce what the agent was.) May I ask how you got your expertise on so many facets of a house?

A. She must have used a product you have, so you may already have checked labels and found the appropriate one. If not, try any product that looks plausible. You may also try washing the areas of the tub that have not been affected with a mixture of 1-part fresh Clorox bleach to 3-parts water. If you see a positive effect, you may want to increase the bleach proportion until you get the desired results.

I have learned what I know from 52 years in the residential construction business after a 10-year career in academia, teaching and pursuing an advanced degree. My experience has taught me how to do research and that all problems generally have a solution that you must be willing to look for in any place possible. In doing so, I developed many valuable contacts in research facilities, the industry and other related fields. I have also attended many seminars, as well as taught some, where I met fascinating people who have become valuable sources of information. It's been a wonderful half-century ride. Thank you for asking.

In a recent article, you note, "If your downspouts are connected to underground pipes, these may need to be watched -" Have you heard of cases of plastic underground rainwater pipes being broken or pulled apart by ground settling? I suspect that is what has happened to my system, as rainwater is overflowing the tops of some of the system's inlets, but the bottom of the clean out standpipe for the system is dry, intruded by roots and soil and cocked at an odd angle. Who would have experience in investigating and repairing such a problem? A plumber? An excavating contractor? A septic contractor? A landscaping contractor?

A. Yes, it is possible that frost may have caused the problem if any underground pipe was not buried below the frost line in your area. However, if I understand correctly, you are referring to a vertical standpipe that was installed to "clean out" the system. This is an unfortunate construction feature that too many builders install under the erroneous impression that you can clean the foundation drains with a garden hose. The more water you would put in those pipes, the more likely it is that the soil becomes compacted.

If I am correct, the downspouts are discharging into the foundation drain - a gross mistake, as any debris from the gutters will contribute to the problem. Gutters and downspouts should either discharge onto the ground or have their own underground piping below the frost line that leads to a safe and accessible outlet, which should be monitored to make sure it has not been obstructed. If I'm accurate, you have a major and expensive job to redo the foundation drain and install a separate drainage system for the roof water. A properly built foundation drain should not silt and fail. A septic contractor or a plumber with a jet service and camera would be the best person to investigate.

Your column always interests me. This week we were horrified to discover "popping" paint on the west side of our big old house! The house was built in the 1880s, and we have lived in it for 38 years. It was originally a frame house, and back sometime in the 1920s or 30s, a thick coat of heavy cement-like stucco was put on it, which made the walls quite thick. We have enjoyed this fortress and have had the outside painted three times since 1971.

Sometime in the 1980s, at the second painting, we treated with PPG's product PITT-FLEX. It did its job, and held up well, allowing the surface to expand and contract with changes in temperature. The stucco was painted both times with PPG's latex paint. In October of 2000, a different, highly recommended painting contractor did a whole-house treatment on the outside, with what seemed to be a very thorough and diligent prep. He used all Benjamin Moore products, latex, acrylics, etc. We were very pleased with the job, and it seemed fine, until a few weeks ago, when we discovered large chunks of paint, about 4 inches square, out on the lawn. Looking up, we see the bare stucco exposed in those patches, and none of the previous paint even visible!

This condition is only on the west side of the house. We don't think moisture has gotten under it, as our box gutters have been maintained and cleaned out frequently. The painting contractor stopped by to take a look and seemed to be as puzzled as we are. He plans to come back in a couple of weeks to discuss what to do. But before I do any repainting, I want to know what caused this to happen.

A. Your description indicates that the weight of the multiple coats became too much for the bond of the original paint coat. It is possible that the original preparation of the stucco before the application of the first coat may have not been as good as it should have been, resulting in a weak bond between the stucco and the first coat of paint. The fact that it occurred only on the west wall indicates that you must get a strong afternoon sun, which causes greater expansion and contraction than on other walls and resulted in complete failure.

The bad news is that what seems like sound areas on that same wall are probably not, and you may experience more paint failure as time goes by. You can opt to patch-paint the bare areas as they occur, but the best course of action on the west wall is to remove all the paint by pressure-washing (as long as there aren't cracks that would let water in and cause further problems) or, preferably, by hand scraping - a tedious and expensive job, but a safer one. You may want to wait to do the other sides until significant failure develops, giving you somewhat of a financial respite.

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.

© 2009, United Feature Syndicate Inc.