Q. Can you tell me how to overcome a loud grating noise my walnut chairs make when pulled over a tile floor? I have tried plastic covers over the tips of the legs, but they created a spine-chilling noise as unpleasant as the noise of the wood. Rubber-crutch tips make it impossible to move the chairs without lifting. Metal tips are also noisy, at least the ones I have tried. A. Try glides that look like nails with carpet-covered heads. They should be almost silent and will also let you move the chairs easily. You install them by driving the nail into the end of the chair leg. I like to pre-drill the legs with a bit slightly smaller than the diameter of the nail. This makes them easier to drive into place and eliminates any chance of splitting the leg. Q. My electrical system has always been grounded via a cable leading to a water pipe. Recently I replaced some of the old metal plumbing in my home with plastic pipe. It now occurs to me that since the plastic won't conduct electricity, my ground may no longer be effective. True? A. It depends on where the plastic is in relation to the grounding cable. If the plastic is between the cable connection and the point where the pipe runs into the earth outside your home, the ground is indeed no longer effective.

If that's the case, you should have an electrician come out and remedy the situation. He may move the cable connection to the other side of the plastic, or drive a copper grounding-rod into the earth and connect the grounding cable to that. Meanwhile, you are living with a dangerous situation. Q. The screen door on my porch keeps rubbing on the threshold. This makes it hard to close the door. I took the door down and planed the bottom and it worked fine for awhile. But the problem came back. I think it may be caused byswelling of the wood during humid weather. If so, is there some way to seal the wood? A. There is no truly successful way to seal wood against moisture. But then I doubt that you'll need to. My guess is simply that your door is sagging. The solution to that problem is a turnbuckle-style door brace. Any good hardware store should have one.

Install it high on the hinge side of the door, low on the latch side, then tighten up the turnbuckle. It should lift the door's sag and keep it from reappearing. Q. I recently repainted my son's dresser. He outgrew the bright glossy enamel finish. Now the new new paint -- a latex semi-gloss enamel -- is falling off in sheets. Is it true that type of paint won't stick to an old oil-base enamel? A. It's true if the old enamel is dirty or very glossy. Thorough sanding before you painted would have elminated the problem by cleaning the old enamel and roughing it up, creating "tooth" for the new finish to grip. Try sanding off the new paint. If it's as loose as you say it should come off fairly quickly. If so, scuff up the old enamel with No. 220 sandpaper, taking care to remove the gloss. Then repaint.

If the new finish won't sand off easily, you'll have to use paint-remover and strip down to bare wood. That can be a lot of work, so give sanding a chance first. Q. We are moving into an all-brick Tudor house with plaster walls. My husband is of the impression that if we put Sanitas or Wall-Tex on the walls, the walls would be ruined and the covering could never be removed for repapering or painting. He also feels that you cannot put nails into plaster walls for hanging pictures. Is he right? A. No, he's wrong. Any kind of wallpaper can be removed, although the types you describe require a bit more work than plain papers.

As for nailing into plaster, no problem. Sometimes the wall will chip a bit when the nail is started, but not if you drive the nail through a piece of tape pressed firmly over the spot you wish to nail into.