Question: Our home is 11 years old, and we live just south of Pittsburgh. Our basement has flooded quite a few times. Multiple factors caused the flooding, but we believe that problem has been solved.
The issue I now need help with is a west-facing, underground basement wall. It has possible mold damage. I scrubbed it three times with a 50/50 bleach/water mixture. Some of the areas lightened up, but the spots are still there.
When I asked an employee at our local home improvement store, he advised removing the original paint, then using hydraulic cement, then repainting the wall. Is this information correct? If so, how do you suggest removing the paint? Is there any other option that might be easier, yet as effective? I have enclosed pictures of the interior wall as well as pictures of what is on the outside of this wall. Any advice you can suggest would be greatly appreciated.
— Pennsylvania, via email
A: The only reason to use hydraulic cement is to fill holes through which water gets in. I don't see that on your photos.
Since I do not see any paint peeling, my guess is that the block wall was painted with a cementitious paint. If that is the case, the coating can probably be removed using Peel Away 4 Cementitious Coating Removal System. Peel Away 4 works on most masonry coatings. You should be able to get it in well-equipped and experienced paint stores, but if they don't carry it in stock, they should be able to order it for you. Otherwise, you can buy Peel Away 4 online at www.dumondchemicals.com.
However, removing the coating may not get rid of the stains. Your photos show what look like rust spots and not mildew, which the bleach treatment should have removed. If you are certain that the moisture problem has been solved, you might try Bulls Eye 1-2-3 Plus applied over the existing coating. It should hide the rust stains. If you don't notice any peeling or other problems after a few months, you can then paint the walls with any top-quality latex paint.
If that does not work, use Peel Away 4 and start all over.
Condensation concern
Q: We have a cedar-sided house. This past summer, we had the house spray-washed and stained with two coats of Olympic cedar stain.
We recently had our first cold weather, and for the first time ever, we have condensation on the inside of some windows. I talked with the contractor, and he assured me that he had adequately caulked around all the windows.
There are, however, some small areas around the windows that are not caulked. The way the cedar boards lap over each other creates a small lip on the bottom edge of each board. (I hope this makes sense.) Each lip is about a quarter-inch wide. Some are caulked, while others are not.
Is it possible that these very small spots on the boards around the windows could be the cause of the condensation buildup? Could it be attributed to all the water that was sprayed onto the wood, and it takes time to totally dry out? Or is it a combination of both — or maybe none of the above?
Any insight to what may have caused this would be greatly appreciated.
— via email
A: Did the power-washed siding dry completely before the stain was applied? It is always a good idea, after power-washing, to check the moisture content of the wood prior to applying any coating.
All experienced painting contractors should carry a moisture meter and check the surface in many places before starting a job. But I don't think this is entirely your problem, although it may contribute to it to a very minor degree.
It is more likely to be the fact that so much caulking was done, sealing any exfiltration and infiltration paths your house may have had before the caulking and staining.
In houses that are not tightly built or made tighter with caulking and other means, upper-level exfiltration through various cracks and openings encourages infiltration on the lower level. This process exchanges the air and the house breathes.
Keep in mind also that all houses ventilated by open windows in the summer accumulate a considerable amount of moisture from the outside air. This moisture takes weeks to dissipate once the heat is turned on.
It is likely that your house was not as tight before the caulking, which helped prevent condensation on the windows.
This is not to imply that you should not have improved the energy efficiency of your house; it simply means that you need to ventilate the house. This can be done by opening windows in mild temperatures or by mechanically ventilating it by using bathroom and kitchen fans until the relative humidity is considerably reduced. You will need to provide an air intake, such as a slightly opened basement window, etc., for this to be effective.
Another option is to have an air-to-air heat exchanger installed. You may also look into your lifestyle and see if you can reduce the relative humidity by eliminating some moisture sources.
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