Q - Last year I sanded the oak floor in my bedroom. I went down to fresh wood, then sealed with shellac and put on two coats of urethane floor finish. Now the finish is starting to chip and peel. I can't understand it - I thought these new urethanes were supposed to be so great. What's the problem, and what should I do about it?

A - Bad news: Most urethanes should not be used over shellac. The instructions on the label usually warn against it; the two are not compatible. Solution? Sand everything off and start over. This time, don't seal with shellac. The urethane is its own best sealer.

Q - I want to repaint my kitchen. The man at the paint store says if I don't sand the glossy paint presently on the walls and cabinets, the new won't stick. Is he right? All that sanding would be a lot of work.

A - The man is right when he says you'll have adhesion problems painting over glossy paint. But you don't have to sand everything. It's a quite a bit easier to use a deglosser. This is a liquid (and your paint store should have it) that you rub on the walls. It etches away the gloss of old coating to give the new paint a better grip. Note: Using this stuff eliminates a lot of the effort and dust of sanding, but deglossers contain strong solvents. Be sure to provide plenty of ventilation to carry away fumes.

Q - I recently started a cabinet using birch plywood. After cutting out all the parts and beginning assembly, I discovered that all the parts were slightly out of square. At first I thought it was my fault, but now I suspect my framing square, Is there any way to check it without special calibrated equipment?

A - There's a very simple check. Place the tongue of the square against the straight edge of a sheet of plywood. Scribe a line along the blade, then flip the square over and scribe a second line over the first. If the second line covers the first, your square is square. But if the two lines form a "v" the square is off.

Q - My husband and I are thinking of a wood-fired boiler as an alternative to our oil burner. Do you have any suggestions as to the best ones on the market?

A - I don't want to recommend any specific brands, but I do have some advice. First, consider a dual-fuel furnace, one that can burn both oil and wood. The biggest advantage of this type is that it will run on wood as long as you stoke it, but will automatically switch to oil if you don't. This gives you the freedom to ignore the furnace or to go away on a winter vacation. But before you buy anything, be sure the unit is approved by your local building inspector. Most multi-fuel furnaces are not approved; if you put one in you could be forced by law to remove it.

Q - I want to repaint my kitchen. The man at the paint store says if I don't sand the glossy paint presently on the walls and cabinets, the new won't stick. Is he right? All that sanding would be a lot of work.

A - The man is right when he says you'll have adhesion problems painting over glossy paint. But you don't have to sand everything. It's a quite a bit easier to use a deglosser. This is a liquid (and your paint store should have it) that you rub on the walls. It etches away the gloss of old coating to give the new paint a better grip.Note: Using this stuff eliminates a lot of the effort and dust of sanding, but deglossers contain strong solvents. Be sure to provide plenty of ventilation to carry away fumes.

Q - I bought a steel log caddy so I could store a day's worth of firewood indoors near my woodstove. It keeps the wood organized, but bits of bark and splinters of wood are making a real mess. The stove is in my living room so this debris is causing a real problem. Any ideas?

A - I solved this problem by building a box for my firewood. You can duplicate it by using 3/4-inch plywood. For best efficiency, size the box to the length of the logs your stove will take. I burn 17" logs, so my box is a bit over three times that long inside. This lets me fill it with three rows of logs and wastes very little space. You can paint the box or cover it with plastic laminate such as Formica. I had my lid padded with foam and covered in Naugahyde to provide a comfortable bench seat. It cost $20 and added greatly to the appearance of the box.