Q: I live in an apartment where a radiator was installed recently in one room to provide additional heat. Now, every time the steam comes up, there is a loud banging noise in that radiator or in the pipe next to it. The noise lasts a few minutes. Can you tell me what can be done to get rid of it?

A: First, check the inlet valve to see if it is all the way open. On a steam radiator this should be fully open or fully closed. The next thing you can do is wait until the steam comes up and the banging noise starts. Quickly unscrew the vent valve (at the opposite end of the radiator) and leave it out until steam comes pouring out. If this stops the banging noise, the vent valve is clogged and should be cleaned or replaced: (you can buy one in a plumbing supply store).

If a new vent valve doesn't solve your problem, the radiator may not be standing level and water may be getting trapped inside. Put a level on the radiator. If it is not level or if it pitches slightly toward the connecting pipe, wedge a thin piece of wood under the legs at the opposite end (farthest from the inlet valve). This will help water drain out more quickly and not get in the way of incoming steam.

Q: We have a cedar shingle roof that was covered by two layers of regular asphalt shingles laid on top. We now want to insulate the attic under the roof, but are afraid to do so for fear of trapping moisture that would cause the wood shingles to rot. The attic is not heated. Any suggestions?

A: Insulation alone will not cause the wood shingles to rot. Moisture (which can lead to rot) only occurs when there are problems with ventilation above the insulation. The insulation must be installed to allow air to circulate above it -- between it and the wood sheathing. There should be louvers or vents in the attic to permit outside air to circulate above the insulation.

A: My wood floors were scraped, stained, and then finished with polyurethane -- a finish I thought would prevent scratching. But I am starting to see scratches. Can this floor be waxed to help prevent scratching?

A: It can -- and should -- be waxed. Polyurethane is tough, but it still can scratch. Wax will help protect it against scratching.