When tackling a fixer-upper, take it from the top
Q. I am buying a family house in Cambridge. A two-decker from the 1920s, it needs a new roof, has had ice dams and leaks in the attic, chimney bricks are falling off, gutters are rotting, the attic has never been insulated, and we had a bat in December. Where can I start?
FLORA APHANAS, Cambridge
A. Sounds like my house 45 years ago. If I knew what I was in for, I would have jumped the deposit and gotten out of there. I figured it would take me three months to fix. Nine years later . . . But it all worked out.
If you can afford it, hire a renovation contractor, who will schedule the work and is delighted to have a challenge. The other way is to hire your own contractors according to the job. Start at the top; have a new roof installed before it gets worse. Then consider things you can do yourself, such as laying insulation on the attic floor, which is the highest priority for insulation. As for insulation in the walls, that should be done by a professional. You can take down those old gutters, and you might be able to wait a while before considering new ones. The roofer might offer to do gutters and rebuild the chimney, or hire it out.
If you have not had any bats since December, treatment is a low priority. But any decayed eaves, where there are holes for bats and other critters to enter, should be fixed as quickly as possible. They are the next priority after the roof. Eventually, if we live long enough, the house, even a two-decker, will be a showpiece.
Q. My running water comes out cloudy and gray. What is happening and is it hazardous to our health?
WORRIED
A. Worry no longer. It is harmless. It is bubbles in the water, thousands of them, most common, but not limited to hot water. To determine if this is all true, fill a glass with the water and let it stand for a minute or so. It will clear.
Q. I have a chip in my plastered wall, 1 1/2 inches long and 1/2 inch deep. I tried sanding it, but the edges still show. What can I fill it with that will not show?
H.G., Sudbury
A. Good old joint compound to the rescue. This stuff is the same thing used to fill nail heads and taped joint seams in dry wall. It is ready mixed. Fill the chip, smooth off, and let set, sand smooth. Paint with the same paint you used on the wall. It will never show.
Q. Just a month ago, I developed a green stain on my 20-year-old wall-to-wall carpet. What in the world is it, and how can I clean it off?
JOE WILEY, East Boston
A. I think it's algae, a form of one-celled seaweed. Use Bayer Moss & Algae Killer. It's a potassium soap of fatty acids, sold at Lowe's. I got that from Michael Good of Brookline. Bleach usually takes care of it, but can damage the carpet unless it is a very weak solution. Another thing to try is Oxi-Clean, an oxygen bleach, or one of the new carpet spot cleaners, but best is to scrub with detergent and water, and rinsing. Ammonia can work, but only if you have not put bleach on the carpet. Any mix of ammonia and bleach is deadly.
Q. In my new kitchen, the range vent does not go outside. Is that wrong?
CONCERNED
A. It is not wrong, but if the kitchen was completely redone, the vent should have been set to blow outside. That would have been the best and easiest time to do it. But it is not a big concern, because many houses do not have exhaust fans, and no apparent harm occurs. If your fan has a filter, change it every six months or so, or if the filter can be washed, every three months.
You do not have to turn it on at every cooking time, only if you accidentally create a lot smoke. So if there is no fire, turn on the fan and open a window or two. The smoke will clear the room, and the house, in minutes.
Q. Two questions from owners of Trex composite decks, which have developed black marks, and what to do about them.
PERPLEXED and WORRIED
A. Many people seem to think that materials other than wood will be resistant to mold (black marks and tiny black dots). Sorry about that, there are very few materials that are resistant to mold. Anything light in color, shiny, and hard will resist mold. Those materials include stainless steel and glazed ceramic tile. If a paint is light enough, shiny enough, and hard enough, it will resist mold. Why light color? A light color will not absorb as much heat and will not stay wet for very long and will cause less condensation of water, which mold thrives on.
The cure is bleach and water. There is a new product on the market called Moldex, which is supposed to kill mold, and maybe it does, but when I went to buy some to see if and how it would work, it cost $7 a pint, which is way too much if you have a lot of mold. So I didn't buy. it.
Handyman on Call also appears in G on Thursdays. Peter Hotton is available 1 to 6 p.m. Tuesdays to answer questions on house repair; call 617-929-2930. Hotton chats online about house matters 2 to 3 p.m. Thursdays, at www.boston.com. Hotton can be reached at photton@globe.com. 
