Question - I'm getting quite a few pops in my hot air heating system whenever the heat comes on or goes off. Sometimes it's enough to wake me - and everyone else - up at night. What are those pops, and can I stop them? Howard Hull, Acton, Mass.

Answer - Those pops are an old story, and they will stop when the heat goes off for the last time in spring. What is happening is that the metal ducts expand when they heat up as the heat comes on, and contract when they cool off when the heat goes off. This expansion and contraction is movement, and when metal moves, particularly if it is held tightly in place, it will make the noise. If there were room for the metal to move into, it would be less likely to pop. The same thing can happen with copper heating pipes.

So much for the reason.

The cure may be twofold. One is to make sure the ducts are not too tightly secured in their hangers, say, along the basement ceiling. If they are tight, you can loosen the hangers. That could cause another noise; the sound of the ducts moving on their hangers; it might be less than the popping sound, however, and not loud enough to wake you at night. And to correct this, you could put a soft gasket between hanger and duct.

The other cure is to cut the ducts in the middle of their span, cut off an inch of duct and connect them with a flexible material such as canvas. This will give the metal a chance to move into space rather than against itself, eliminating the popping.

Incidentally, you can turn the heat all the way down at night so it won't come on to wake you up. At least the popping won't occur at night, and if your house is well insulated, it won't be intolerably cold when you wake up.

Question - I am redoing several rooms in my house, before the gardening season starts: washing, painting and the whole works. What order is the best way, or at least the most efficient way, to do it? C.B., Quincy, Mass.

Answer - Order of battle, whether washing, sanding, papering, staining, varnishing or painting: 1 Ceilings. 2. Woodwork. 3. Walls. 4. Floors.

Some specialists may argue over the woodwork/walls order, but the handyman feels that it's easier to do woodwork first, because you don't have to worry too much about getting paint on the wall when you're trying to paint the edges of window and door frames. If you do slop a little paint on the walls, new paint or wallpaper will cover it. By the same token, however, you could argue (and some do) that doing the walls first is better because rolling walls is likely to spatter a little paint onto woodwork, and if you do, you can cover those splatters with new paint on the woodwork.

I think it's half a dozen of one and six or eight of the other. Take your choice and do what's comfortable for you.

Another question the naysayers might come up with is, why do the floors last (sanding and varnishing)? If you do, you'll get sawdust all over the freshly painted and wallpapered room. True, and perhaps a good point, except that the sawdust is more easily swept and wiped off a clean, new surface than a dirty old one. Besides, if you do the floors first, you'll have to really protect them while you do the other parts of the room. There's nothing like a big scratch or spilled paint black water marks on a brand-new sanded and varnished floor. It's like the first dent your spanking brand-new super-nice car gets. It's enough to make a grown handyman cry.

Question - Please answer how I can clean water and stain spots off a slate floor. E.B. AXEL, Virginia Beach, Va.

Answer - Slate and unglazed tile are notorious for their susceptibility to stains from water and other causes. The stains usually show up white. To remove them, dip a piece of steel wool in paint thinner and rub. If the slate was finished in any way, rubbing them with steel wool might take the finish off.

If there is no finish already on the slate, after cleaning the stains off, you might consider treating the slate with Future; this will darken the slate and give it a shine, but it will make the slate a little more stain-resistant.

Question - I built a unique gate that look great but isn't working. I built two brick pedestal-type posts, one on each side of the driveway. Then I glued a gargoyle (a hollow statue made of some sort of resin) to the top of each pedestal-post, using an epoxy adhesive, then strung a heavy chain spanning the driveway from the gargoyles. One gargoyle stuck for a month, the other for a year. How can I reglue them permanently? SIGORNEY STREET, Jamaica Plain, Mass.

Answer - How about suspending the chain from the top of the posts instead of the gargoyles, then regluing the gargoyles. The chain now is exerting considerable pressure on the gargoyles, and any constant (and sometimes moving) pressure can break almost any glue joint, epoxy or not.

Or, screw or bolt a pedestal top (sort of platform of pressure-treated wood) on each posts, then bolt or screw the gargoyle on that pedestal. That way you can leave the chain hooked to the gargoyles.