QUESTION: We just purchased a very old house which has wooden shingles on the roof. We bought it with the understanding that the shingles were badly in need of repairs and would have to be replaced. We would like to use asphalt shingles, but have been told they cannot be placed over wooden shingles. Is this so, and would not the cost of removing the old shingles send the price of the reroofing to the sky?

ANSWER: Asphalt shingles can be installed directly over wooden shingles, but only if the old shingles are in fairly good shape and if there is not another layer of shingles under the present covering. Your roofer is the only one who can determine what the situation is in your case, since the condition of the framework plays a part in the decision on how the job should be handled. It is difficult to see how repairing the shingles will be easier than removing them. Also, when asphalt shingles are installed over wooden shingles, certain kinds of extra work must be done, such as placing feathering strips under the butts. In many cases, removing the old shingles may be a lot easier than roofing over them.QUESTION: I want to reroof our house and would like to do the job myself, since I have had some experience in working on roofs. Any tips that will help me? For instance, what is the easiest way to determine the pitch of my roof?

ANSWER: That last question gives some cause for concern. Having worked on roofs, you should know about such things as determining the pitch. However, it is found by measuring how many inches it rises for every foot it runs. Roofs with slopes of 4" or 5" per horizontal foot are safest and easiest for the do-it-yourselfer. Steep slopes and high roofs, or those with many angles, dormers or gables, are best left to the professional. If you do the job yourself, there are certain safety precautions that should be observed. Wear rubber-soled construction-type shoes for secure footing. Apply the shingles on clear days when it is warm but not hot. Do not reroof in wet weather or when the temperature is below 40 degrees. Reroof only when the roof deck and existing shingles are dry, since moisture makes roofs slippery and dangerous. Lift only easy loads. Secure ladders, top and bottom, and keep the roof surface free of debris. Don't allow ladders to come in contact with power lines. And place shingles and tools where they won't slide off the roof, but to be sure, keep people away from the work area. Besides all these precautions, use your common sense.

QUESTION: We have our roof covered with asphalt shingles. There are two layers of the same kind of shingles there already, but our local roofer says the roof deck is strong and will support a third layer. Should I believe him, even though I have read that only two layers of shingles are safe?

ANSWER: If he is a licensed roofer, he should know whether the deck will support a third layer. However, just to be certain, check your local rules on construction. Some communities will not permit the use of a third layer of shingles.

QUESTION: I want to finish a piece of unpainted furniture and would like it to have a reddish tint. I read this can be done with crocus cloth. If so, where can it be purchased? My local hardware store does not have it.

ANSWER: Crocus cloth can be bought in stores that carry finishing materials. Some paint stores carry it. So do some home centers. It is used quite often by jewelers. Yes, it gives certain woods a reddish tint. Wood finishers who use it do so after a coat of sealer has been applied. However, it should be used only on dark woods. Test it first before you apply it to a work piece. Once applied, the tint is difficult to remove.

"A Homeowners Guide to Quality Roofing," including an asphalt shingle color guide, can be obtained by sending $1 and a long, stamped, self-addressed envelope to Know-How, P.O. Box 477, Huntington, NY 11743. Questions of general interest will be answered in the column.