Humidity to blame for door problems
Q. Our 1998 house has three bedrooms upstairs. The door to one bedroom won’t close fully in winter, but is OK in summer. The door to a second bedroom won’t close well in summer, but is OK in winter. The third door works fine year-round. What is going on?
A. I think the mysterious door problems are symptoms of a common property of wood: it expands and contracts as the relative humidity changes.
When humidity is high, wood expands; when humidity is low, wood shrinks. The swelling and shrinkage occur across the grain of the wood, so in the case of doors it could affect the width slightly.
Swelling is most common in summer, when humidity is often very high, and shrinkage usually occurs in winter.
Swelling and shrinkage are often not much of a problem in wood that is well finished on all surfaces, since the finish inhibits absorption and drying out of the moisture that causes the problem.
It is possible that the doors giving you problems are not finished on some surfaces, possibly the top and bottom edges. It might help if you waited until each door is performing as it should, then remove it from its hinges and check for unfinished edges.
Give these a couple of coats of shellac to seal them, then give the entire door an additional coat of paint or varnish to help protect it from moisture.
Q. I have a floor that had tiles on top of linoleum. The tiles were cracked and broken so I removed them, but how do I get the adhesive off the linoleum?
A. You don’t give much information, such as what kind of tiles these were or how long they have been on the floor, but the answer would be the same in any case: I don’t know of any practical way to remove the adhesive from the “linoleum” without destroying it. You should not even attempt it.
The best thing to do is to remove both the tiles and the floor covering under them and start with a fresh surface. It will probably be necessary to install a new underlayment over the subfloor, suitable for new tiles or whatever type of finish flooring you choose.
Just one of the problems with your old flooring is that if it was installed before about 1978, the adhesive or the tiles themselves could contain asbestos, a health hazard if particles are breathed.
Before you do anything more, you should read “Asbestos in Your Home,” which is available on the Internet at www.epa.gov. Write Asbestos in Your Home in the search space. This publication will give you some valuable background on asbestos and what to do about it.
If a hazard exists, you should have the old flooring removed by an asbestos remedial expert; you’ll find more information on this in “Asbestos in Your Home.”
Q. We had fungus-resistant shingles installed on our roof after having a problem with stains. The shingles contain copper granules, and we were dismayed to discover later that copper released by the fungus-resistant shingles can cause severe corrosion to aluminum rain gutters. We have aluminum gutters. Would the zinc strips sometimes recommended for fungus protection have the same effect on aluminum gutters?
A. A chemical reaction called galvanic corrosion occurs between some dissimilar metals, and copper seems to be a leading culprit. However, zinc is often used to plate steel (galvanizing) to protect it from corrosion. Even aluminum is sometimes given a zinc coating to reduce corrosion.
This is how Shingle Shield ( www.shingleshield.com), a leading dealer of zinc strips for roofs, addresses the matter: “Zinc and aluminum are adjacent on the electro-chemical scale. … The fact that zinc and aluminum are so close indicates that there would be little or no problem even if they were to come in direct contact.”
Also, aluminum gutters are generally given a baked-on coating to protect them from corrosion. None of this is to say that zinc strips will never have some effect on aluminum gutters. If any readers know of such cases, I would like to hear from them.