Q. I had a new roof put on in the early summer and now have leaking at a bottom interior corner of a skylight. I can’t see anything on the outside, except one shingle may not be snug against the frame. There is nothing above the skylight up to the ridge. The roofer is coming back this week. He seems surprised. I don’t think I want a caulking job here.
DAVE KEAVENY, SOUTH DENNIS
A. I don’t know if the skylight is old or is new from the new roofing job, but caulking will do no good around a skylight.
Since the leak is in the interior, there is chance that the skylight itself is leaking between the glass and the frame, or the frame and the roof. Usually the leak is due to faulty flashing. If the flashing is a thick rubber strip going under the shingles and up the sides and top of the frame, it is likely to leak, and should not be used.
The proper flashing on a framed skylight is step flashing, individual aluminum pieces shaped into an “L” shape, with each shape starting at the bottom of the frame, with one leg going up the frame and the other over a roof shingle. There is an “L” shaped panel for each course of shingles, and they are under the shingles.
I don’t know why the roofer seems surprised, but let’s say again that caulking is not the answer. Any caulking used should be roofing cement in conjunction with the flashing.
Q. My deck was converted to an all-weather porch, and there is air conditioning in the porch via two ducts in the ceiling. Both are covered with insulation, and one duct is collecting water which is running out the grille. How can I stop it, and why is the water in only one duct?
FRED SMITH, WOBURN
A. The duct itself is cold, probably cooler than the air going through it, and the air condenses and water gurgles out the grille. You could insulate the ceiling, and check the duct insulation for tears and holes that make the metal work cold.
Q. The American Standard toilet in my condo is only 11 years old, and any time solid matter is flushed it will overflow. The flapper in the toilet allows it to flush twice. My super could not find anything clogging the pipe and said if it happens again the bowl or whole toilet needs to be replaced. Should this be happening with a toilet that is only 11 years old?
A. When you say the flapper allows the toilet to flush twice, do you mean that lightly flushed, it will flush just 1 gallon of water or so, and if heavily flushed, will allow more water to go down? An 11-year-old American Standard toilet should not fail, unless it is defective. Try this: use a plunger to force debris up or down. If no luck, call Watertown Plumbing and Heating supply to see if they can find something wrong. Or contact the dealer where you bought the toilet.
Q. I plan to improve my basement. It is dry; ground water does not get in, but it is damp enough that I run a dehumidifier full time. Is the wall and floor waterproofing paint/sealant that I hear about a good way of improving?
JHM, IN HOTTON’S CHAT ROOM
A. Some good questions, and some reasonably good answers. First, stop using the dehumidifier. It works well enough to clear the air of water vapor, but can also work too well, pulling water vapor through the floor slab. So, ventilate the basement for starters. The only waterproofing element to use is Drylock, which stops seepage. It will not work on floors. Ceramic tiles are the best thing to use on the floor.
As for insulating, the ceiling is relatively easy to do. Walls, however, are best done by professionals, who now use a high insulating covering directly on the concrete foundation walls. Two of these are Owens Corning Basement Finishing System and SoftWall Finishing Systems. Google others at Basement Insulation.
Q. During our “Sandy storm” a piece of my vinyl siding was caught by the wind and the end of it popped out from the corner. Can’t quite figure out how to get the end tucked back under the corner piece again. Any advice?
A. Vinyl siding is installed using a special tool that allows each strip of siding to be locked into its neighbor. The tool is also used to unlock the siding. You need one of those tools, and since I am not sure they are sold in stores, call a vinyl siding installer who can make short work of that repair.Peter Hotton is also in the g section on Thursdays. He is available 1-6 p.m. Tuesdays to answer questions. Call 617-929-2930. Hotton (firstname.lastname@example.org) also chats online 2-3 p.m. Thursdays. To participate, go to www.Boston.com