Q. I read about using boiled linseed oil as a primer/sealer in the Globe; would that be the best thing to use on old bare wood on a door sill that I do not want to paint? I just want something to keep it from getting split and old -- something to keep it moist -- the house was built in 1811 and the door sills have always been bare wood.
A. I don't think boiled linseed oil is best on bare wood. It must be wiped off with a dry cloth or it will stay sticky forever, and it is a soft finish that can collect dust. It works best as a sealer under polyurethane varnish. You are better off giving the wood, if it is an interior door sill, two or three thin coats of a high-gloss, oil-based polyurethane varnish. On an exterior door sill, use a single coat of semitransparent stain. Another coat perhaps in five years.
Q. I had a beautiful mahogany front door installed 20 years ago. The original finish (stain and polyurethane varnish) lasted three or four years. Over the years the door got very hot in the summer sun and also in the winter sun when a wood storm door covered it, and it has turned black and the varnish has flaked. How can I restore it? And how long should a good finish last? I don't want to paint it.
BOB CAREY, Norwood
A. The life of the original finish, three to four years, is rather good. A new one is unlikely to last longer; in fact, a year is usually the limit. You can do one of two things to preserve the good looks of the wood. First, strip all finish and stain by sanding to the bare wood. Your first option is to apply one thin coat of a semitransparent stain. No varnish is needed. You may not like this look, but it will last five to seven years. You can't make it look better by applying a second coat. The alternative to this method is to apply a penetrating stain (Minwax is of top quality), and follow with three coats of a polyurethane marine-grade varnish. You might get another three to five years out of this.
But here is a trick to extend the life of this finish: When the varnish starts to flake a fair amount, sand off the flaking varnish and apply another coat of the varnish. You cannot do anything to stop the darkening of the color.
And, it might be a good idea to take off that storm door; there is too much heat building up between the two doors.
Q. I sanded my cedar clapboards to the bare wood and plan to prime and paint them. Trouble is, I also sanded off the tops of the nails, so they are bright and shiny. I plan to paint the house with an oil-based primer and latex house paint. I think the oil-based primer will help prevent the nails from rusting. Would an extra coat of metal primer over each nail head before priming and painting provide extra protection?
JOE WISE, Andover
A. Oh Joe, you are too Wise. I love it when you answer your own question. That saves the handyman an answer, but it won't shut him up. You really did a job of sanding off the galvanized finish, so the nail heads are very susceptible to rusting. A little dab of metal primer on each nail will do a lot of good.
In the future, if the nail heads rust, you can correct the situation by pulling each bare nail and driving in stainless steel nails before repainting.
Q. Can I have a laminate floor put over a concrete floor, which is on the second story of my condo?
RUTH GORDON, Stoughton
A. In a word, yes. A laminate could be a wood floor, floating or glued down. I have seen such a floating floor and it behaves beautifully, with no double click when you walk on it. The other laminate floor is a plastic, similar to Formica. This is good, too, but if you have a choice, I suggest you opt for wood.
Q.I have read about the invasion of a million caterpillars of the winter moth this spring. Is there anything we an do about them now? Later?br>ROB AHEARN, Tewksbury
A. I too have heard of the winter moth, and somewhere a writer added the gypsy moth, which we have not seen in more than 20 years. We have had the winter moth caterpillars for several years, but last year there were less, so let's hope the South Shore (the handyman's stomping grounds) will have some relief.
There is not much you can do until the worms, which look like little green inch worms, appear in June. Standard treatment for caterpillars is BT (Bacillus thuringiensis), but it is important to use any treatment early, while the worms are at their youngest. You could have your trees sprayed with insecticide. Other insecticides may also be available.
Another treatment is hand picking and squishing. It won't make much difference, but it will make you feel better.
Handyman on Call also appears in the Globe's Real Estate section on Sundays. 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 Boston.com. Hotton can be reached at firstname.lastname@example.org.