Bleach solution will remove mold from roof – The Boston Globe

Q. What do you think of the products and people who clean roofs of various stains? I have quite a few stains, and wonder if I need to hire a roof cleaner, or buy products such as Roof Begone ($30 a gallon) at Ace Hardware. I have one of those zinc strips installed parallel to the roof ridge, but it is exposed only 1 inch and I still have the stains. I treated some lichen with a lot of water, and when the spots finally came off, they pulled off a lot of the shingle. – DAN, Lynnfield
A. Roofs seem to be collecting a lot of stains of late: mold (black); algae (bright green); moss (looking like a dark green fuzzy plant; and lichen. The professionals are capable but very new at this kind of work, and are expensive, so use them when you can’t (or are afraid to) get on your roof. That Roof Begone sounds intriguing, but at $30 a gallon it’s as expensive as some paints.
Or make your own: one part bleach and three parts water, which will kill mold and algae, but algae needs scrubbing and an extra dose of the bleach/water solution. You can scrape off the moss, or treat with a strong stream from the garden hose.
Unless the power is turned way down, it is not a good idea to power wash an asphalt shingle roof.
Finally, those zinc strips will prevent new growth of all these pesky things, but will not remove what’s already there. Other metals that will deter growth of the three peskies are copper and lead.
Q. Warm water is running from the cold water taps in both my kitchen and bathroom. Replacing the fixtures did not solve the problem. How can I fix it? – NANCY, in Hotton’s chat room
A. I assume the water stays hot as long as you run it. (Nancy wrote back to say the water eventually gets cold, but after a while it can turn warm again.) Sometimes a fixture is fed by hot and cold water pipes that are too close together, and the hot water in one pipe can transfer heat to the other pipe if they are too close. The cure is to move the pipes so they are further apart. The fact that the water cools off when it runs a while, then heats up again when it is not running, confirms this. Or, you can insulate those pipes to eliminate the transfer.
Q. My unit is two stories above another tenant who smokes, and I cannot get the old tobacco smell out. Is there a way? – TIRED OF THE FIGHT
A. Don’t give up. There are more and more smoke odor killers available, and many work on what’s already there, but none works to keep the smoke out from another source. So you have to keep doing it, often on a daily basis. If both the odor in the room plus the odor killer does not appeal, then moving to a virgin area (one where there has never been a puff) may be necessary. And who knows how the various treatments are affecting us? At any rate, there are two types that I know of: Fresh Wave ( and Room Shocker (
I would avoid candles, they produce a lot of soot and other contaminants.
Q. The floor of my shower stall is the same as the stall itself, fiberglass or plastic. Recently it has formed sort of a grayish ring around the tub. A man came and cleaned it, but it came back in three months. How can I keep it away permanently? – ALFRED LUONGO, North Andover
A. I think it’s dirt, just as the ring around the collar or ring around the tub is dirt. Try cleaning it with a citrus cleaner. Or, wet the floor with hydrogen peroxide, then pour cream of tartar on, wait overnight, and rinse it in the morning.
Q. I am installing pine baseboard after ripping out old ones to get rid of lead paint. I have to notch around heating pipes. Do I need to use insulation or fire retardant? – GENE, in Hotton’s chat room
A. The heating pipes do not get hot enough to be a hazard. You can caulk around the pipes with a heat-resistant caulking. Nothing else is needed.
Q. I have a big birch log in my fireplace, just for decoration. Recently some black fuzzy stuff appeared on one log. Is it mold? If so, what can I do about it? – MICHELL COBB, Framingham
A. Yes, it is mold. Treat it with one part bleach and three parts water. Simply paint it on. If decay develops inside the log (birch logs decay from the inside out, due to the waterproofness of the bark), burn it in the fireplace or throw it out.
Q. I am taking down my tub sliders and frame. The sliders are gone. The frame is glued to the tile walls and tub. Nothing budges. How can I remove that frame? – JOE, Peabody
A. Apply a solvent such as paint thinner to the glue. It softens the glue, pry off the frame. If that doesn’t work, apply heat from a hair dryer. With everything off, clean off the glue with a solvent. Finding a solvent is hit or miss, but you will succeed.
Peter Hotton is also in the g 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 2-3 p.m. Thursdays. To participate, go to


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