Your Place: Where is the sewer-gas odor coming from?

Question: I live in a double-wide mobile home. I'm getting a sewer-gas odor in the bedroom and family room, which are directly across from each other. There is nothing anywhere else in the house.

I notice this in the early morning and late evening, around midnight. I have checked the vent pipes on the roof - no problem. I've checked under the trailer, and there is no leakage.

Can you help me locate the source or tell me who to contact to find the source? The local plumber has no idea where the odor is coming from.

Answer: If the plumber cannot determine the source, I don't know what to tell you. Odd that it happens at those times and hours.

In my experience, sewer gas can emanate from fixtures with a dry trap or a broken seal, and a dozen other things. Sometimes what we think is a sewer-gas smell is overtreatment of municipal drinking water supplies.

Call another plumber.

Q: We moved into a twin rancher in Northeast Philadelphia, which was built in the late 1950s of brick and stone.

I'm not sure if there is insulation between the outside walls and the wallboard. In the winter, the bedrooms are about 50 to 55 degrees.

We really don't want to put holes in the walls and blow in insulation. Could the outside (side and back of the home, the brick part) be insulated and sided? And would it be cost-effective?

Besides the cold rooms, we are also having problems with damp basement walls. I was told to have the side of my home waterproofed. Would the siding fix both problems?

A: It would probably fix neither.

You might consider having an energy audit done before you side a brick and stone house. In addition, I'd call an insulation contractor, and see if one or both consultations can determine where the cold air is coming from.

Look at the property. Are there evergreens shading it all year? You could remove the trees and plant deciduous ones, which shade in the summer and allow the sun to shine during winter.

Did you check your heating system? Is it operating so inefficiently that it allows your bedrooms to drop down to the 50s during a winter night?

Most of all, putting siding on a brick house is an aesthetic issue. If you've ever driven around rowhouse neighborhoods in Philadelphia, you'll notice that aluminum siding salesmen talked a lot of people into siding their brick instead of pointing it, and covering rotting fascia board with aluminum.

Covering it did nothing to solve the problem. In fact, it likely aggravated the decay.

Q: Earlier this year we converted from oil to natural gas for heating. The oil tank is still in the basement, with about 90 gallons of oil in it. We haven't found anyone willing to pump the oil out.

Also we wonder if leaving the tank in place, with or without oil, is a safety or environmental issue.

A: Last question first. There is no problem with leaving a tank in place, as long as it isn't rusting or leaking.

The first question is harder. Nonprofit groups used to come and pump oil from tanks for use by low-income homeowners. They appear to have disappeared from sight, but if there are any of you still out there, please let me know.

Stucco advice from reader Rick Couche. "The best method I have found to paint stucco is to mix white Portland cement and lime, one to one, then add water to produce a heavy, soupy mixture. Apply it with a whitewash brush, adding bluing if you desire a really white look.

"I've never attempted to tint the mixture to create a color, but if you are after a great white look this is the best, and it is far cheaper [than gallons of paint].

"I've done homes in West Chester and the surrounding areas and they've looked great after 25 years. We've always worked out of five-gallon buckets. It's also a great way to lose weight, because it's not an easy job."

This week on Al's Place: Making sure your drill/driver has a backup battery. www.philly.com/yourplaceEndText