Combating a chipmunk invasion

Q. An army of chipmunks has invaded my stone retaining wall, taking out enough mortar to cause some stones to fall out. Is there anything I can do?

FED UP

A. Chip or brush out the loose mortar, replace the stones, and apply new mortar, very compactly, so it will resist their little teeth and claws. You can buy ready-mixed mortar by the bag. It is called Mortar Mix, sold in big-box hardware and lumber stores. Just add water. You can also try any number of spray repellents. A terrier, kept in a fenced-in yard, can be effective. A hot pepper/castor oil spray may be a good repellent.

Q. When I had a new gas burner installed, the installer said my basement is too small to allow adequate air for the burner to work right. He installed a small vent in the wall and a fan that brings air into the basement when the burner is running. I am afraid the basement will get too cold, and that it will lose heat. What can I do?

GETTING CHILLY

A. Insulate the basement ceiling. That will stop the loss of heat from the basement, which is considerable, and your fuel savings will also be considerable. Another way to solve the problem is to have the installer disconnect the fan, allowing the vent to allow combustion air to go to the burner by natural means. The basement will still be cold but an unoccupied basement, with proper insulation in the ceiling, is supposed to be cold. Chances are very good the small opening in the wall will provide enough combustion air to make the burner work properly.

Q. When I had a big new room attached to my townhouse everything looked great for a while, until a crack showed up where the addition is attached to the townhouse. The crack in the ceiling is a half-inch wide, and about a half-inch from the main wall. Is the addition falling away? Is there anything I should do? Is there anything the contractor should do?

ELAINE RONCHETTI, Cambridge

A. Call the contractor to get an opinion, I think he is obliged to at least cover the joint if nothing else is wrong. What you can do, all other things being equal: Check the walls where they butt up against the main wall; check the joints to see if any have opened up.

The ceiling gap may mean the addition has dropped or pulled away just a little, or just the roof has dropped or pulled away. In the latter case, check the roof where it butts against the main wall. Any crack in the roof may be covered by flashing, which may keep it from leaking. If the room or roof dropped a little, it probably won't drop any further, which is more a hope than a fact.

So, if nothing else moves, I suggest you put up a crown molding along that gap between ceiling and wall. The crown molding will cover about 3 inches of ceiling and 3 inches of wall. A good thing about a trim like this is that if anything moves behind it, there will be enough stress to split the molding or cause gaps between the molding and wall and ceiling, which will be an immediate, visible warning as to what is happening.

Q. I have had electric baseboard heat for 30 years, and it's time to let it go. I have read about liquid-filled electric radiators that take quite a while to cool down, thus saving money. Would these work in my small area? I am restricted by the condo association as to what I can do.

JOHN BURKE, Boston

A. The liquid filled radiators may take a long time to cool down but they take an equally long time to warm up. It is electric heat and no matter how you spin it, it is still electric, and not good in northern climes, and certainly not in New England, where electricity rates are high.

I think you said you have about 750 square feet of living space, and you do not have gas, so I suggest you look into a pellet stove with a power vent through a wall. You've got to persuade the association this will work and will save a bundle. A pellet stove can warm up the space quickly, and the nice thing about the stove is that it can be turned on and off at will at a flick of a switch.

Q.My Victorian house has no chimney caps on the two flues coming out of the chimney. But when the heat or fireplace is not on, I get a sour, wet, burned ash smell from the chimney. How can I prevent that?

SUE, East Boston

A. That smell is caused by a downdraft in the flue, when falling air pushes the odor from the walls of the flue into the house. It does, indeed, smell bad. One cure is to block off the flue that is at fault, which is probably the one serving the fireplace. Block off the fireplace opening, or put a damper at the top of the flue. Top dampers are sold at energy and fireplace stores. Another fix is to light a kerosene lamp or several votive candles in the fireplace, which will get the air - and smell - going up and out.

Q. The felt on the insertable weather strips in my storm windows (Ranger by Streamliner) has worn off, making the windows very loose and subject to air leaks. I think the company went out of business. Where can I find replacement strips?

DICK, Attleboro

A. I think all modern storm windows have these felt strips, which are rigid plastic with felt bonded to them. They are inserted in grooves in the storm sash. If the storms are opened and closed frequently they can wear out. But before getting replacements, check the windows for air tightness. If you can give them a good shaking, they may have worn out. You can put some Gorilla tape on the joints to see if that will keep them airtight. As for replacements, call Harvey Industries, makers of True Channel storms. You might be able to buy strips from Harvey; if so, hope they will fit your windows. Also, Google "storm window weather-stripping." There is a lot of info out there.

Q. The tilers who installed ceramic tile on my kitchen floor left a haze of grout on the tiles. I keep washing and washing without success. I even tried rubbing with a dry cloth. What can I do?

SYLVIA CRONIN, Peabody

A. That haze is grout that has fused onto the tile and will not come off except with acid or physical rubbing. Rubbing with a dry cloth should have worked, if the tiles are glazed. But here is what you can try, as told by Don Adams of Beverly: I use the green plastic pot scrubbers (dry) and a little elbow grease and it removes the haze and shines up the tile with never a scratch. Thanks, Don, and I am sure Sylvia will thank you, too. I am quite sure any color scrubber will work.

Q. I noticed your opinion that a good single-glazed, weather-stripped window and a good storm are virtually equal to a new double-glazed replacement window, so I am looking into having my windows reglazed and the weights re-corded. I found a man who would do that on 16 windows for $1,000. Is that reasonable?

EILEEN MAHONEY, Lynn

A. I think it is reasonable, for all that work comes to $62 a window. Especially compared with $400 to $1,000 for each new replacement window, installed. Be sure your storm windows are tight, and you can be sure the windows are at maximum ability to retain heat.

Globe Handyman on Call Peter Hotton is also in the Styles Section on Thursdays. He is available 1-6 p.m. Tuesdays to answer questions on house repair. Call 617-929-2930. Hotton also chats online about house matters 2-3 p.m. Thursdays. To participate, go to Boston.com Hotton's e-mail is photton@globe.com.