This is a 50-year-old-plus brick home on a slab with pilings. It had underslab plumbing work in last 10 years, and this problem started after that work was done. The only access to this area is through the closet wall.

Someone suggested using spray foam to seal off the area, but I don’t know how you could keep it from just falling to the ground, and the ground is considerably below the slab. Can you help? –Emily S.

A: It sounds to me like the problem isn’t so much with how to stop the moisture from coming up as it is with what’s causing that moisture in the first place. As soon as you mentioned that the problem started right after you had underslab plumbing work done, the warning flags really started waving for me.

I’m very concerned that whatever plumbing work was done either a) wasn’t done correctly or b) triggered another leak somewhere else, which wouldn’t be uncommon in a house that’s more than 50 years old. You certainly don’t want to close off that moisture site around the tub, because you could potentially be ignoring other problems under the house, as well as trapping a lot of moisture under there where it can cause mold and structural problems.

I would encourage you to contact a licensed plumbing contractor who’s experienced in underslab repair work and have them come out and take a look. They can diagnose what problems, if any, you might have with the plumbing, and after that’s taken care of the moisture problems should dissipate as well.

Q: We have a beautiful spiral stairs, railings and wooden spindles, and they need to be painted. What would you suggest? –Kenneth C.

A: First, any old paint that is peeling needs to be removed, and then you need to sand these areas smooth. Next, clean and lightly sand all the old wood to remove dirt, grease and oils, and to slightly roughen the wood. Finally, apply a top coat of gloss or semigloss paint, depending on your preference. Do not use flat paint, as it won’t hold up well in this application and doesn’t look very good either. You can use either latex or oil-based paint, but use a good-quality material.

You can apply the paint using a brush. However, you will get a nicer, more consistent result if you spray the paint instead. If you are spraying, you might also want to consider using pigmented lacquer, which is often used on kitchen cabinets. It’s a durable finish that is also very smooth and attractive.

Getting a good result on something as intricate as a set of spiral stairs requires a lot of patience, and you need to work slowly and methodically to get a good finish. For that reason, you might also want to consider having a professional painting contractor do this for you.

Q: I was on the roof of a friend’s house and smelled sewer odor coming from the pipe coming out of the roof. Is this normal? I never smelled it coming from my vent pipe on my roof. –Ruth C.

A: The purpose of the plumbing vents is twofold. They provide an opening into the drain and waste system that allows the pressure to be equalized so that the water in the drains will flow. It’s similar to the fact that if you punch one small hole in the lid of a can and then try to pour out the contents, they will flow out very slowly. But if you punch a second hole in the lid, the flow increases dramatically.

The other purpose of the vent is to allow sewer gasses present in the system to escape to the outside so that they cannot build up in the system or in the house. How much gas is present in the system at any one time will vary, which is why you may smell it coming out of the vent at one time but not at another.