Handyman on Call

Sound advice for unit owner

By Peter Hotton
Globe Staff / July 21, 2011

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Q. I am in a condo, part of a conversion in an old house, and one wall between my unit and my neighbor’s is thin. All kinds of sounds go back and forth. How can I make that wall soundproof, or at least sound-resistant? The same goes for a ceiling in my bedroom, where the sound from above is hard to take.


A. That flimsy wall is typical of condo converters, who use the cheapest methods they can get away with. The cure for the thin wall is to caulk all joints. A wall just nailed to the floor, walls, and ceiling needs to be caulked, to fill every seam possible. Now build a stud wall of 2x4s or 2x3s just 1 inch from the original wall. Fill it with insulation and cover with a sound-absorbing board, then 5/8-inch plasterboard. The dead air between walls is what stops the sound, which is vibration.

Another way is to apply resilient acoustical channels on the original wall, then screw the sound-absorbing board and plasterboard on the channels. This does the same thing as the extra wall but takes up much less room. They are professionally installed.

The sound in your bedroom coming from above is mostly impact noise, shoes clunking on the floor. An extra ceiling, separate from the one above, plus insulation, will make a difference. You can do this yourself, or hire a carpenter. Other projects are better done professionally.

Q. How can I get bird droppings off a concrete driveway and sidewalk?


A. Wait for rain, the best cleanser of all. If you’re in a hurry, power-wash, or soak with water for a few minutes, then scrub. I like the rain idea.

Q. We have stamped concrete around our pool area. It’s four years old and in certain areas is discolored and dirty looking. Is there a way to clean this or will soap and water do the trick?


A. The stamped concrete is probably compressed, so it should stand up to power washing. If that does not mess up the concrete, go ahead with it. If not, clean with water and detergent to which a cup of bleach has been added.

Q. I am getting a wicked downdraft in my fireplace, especially in winter, when there is no fire burning. I asked some people about it, and they suggested putting in a top damper, one that is operated by a chain or cable going from the damper right down to the fireplace, so I can open and close it myself. Also, the other flue liner is stainless steel. I know burning gas produces a lot of water, but will water affect the stainless steel?


A. The top draft is very good for your problem. Another way, not as good, is to cover the opening of the fire box. Glass doors will not work, and the cover must be well sealed. Water will not hurt stainless steel, but the water (condensate) from burning gas is, I believe, acidic, which can corrode stainless steel, but it will take a long time for it to deteriorate it.

Q. I have a lot of algae growing on my trees and my roof. There is even some lichen, which is light green in color and sometimes comes in circles the size of half dollars. I was talking with a friend about the problem and how to fix it, and I noticed that he has a copper cupola on his garage. The roof just below the cupola is clear of any growths but on each side of the cupola it is loaded with algae and mold. Why is that happening?


A. You just learned, by accident, what zinc and copper can do to keep algae, lichen, and mold from growing. The copper is the secret. Water runs over it, picking up dissolved bits of copper, and continues down the roof, preventing any unwanted growth. You could do the same on your roof, but you want to remove the algae with bleach and water and scrubbing, first. Then install a strip of copper (zinc will also work, and is less expensive) under the next highest shingles the full length of the roof, with 2 or 3 inches of the strip showing. Roofers can do this too.

Globe Handyman on Call also appears in the Sunday Real Estate section. He is available 1-6 p.m. Tuesdays to answer questions. Call 617-929-2930. Hotton ( also chats online about house matters 2-3 p.m. Thursdays. Go to