EVELYN ROMAN, Needham

A. Yes. Turn off the lights, ho, ho, ho. But to do it right is no big deal; Paint the tack heads with a little dab of paint to match the color of the carpet. Any kind of flat paint will do, although I think an oil enamel will be best; just repaint if and when it wears off.

Another possibility, if the carpet is relatively deep-piled, is to countersink the tacks a bit so they are deeper in the carpet, which might cast a shadow over the tack heads.

Q. I took up the old carpet in my basement playroom. The installer of the new carpet put it down with nailing strips along the borders of the room. At the fireplace hearth, he could not put down a strip, and suggested I install a thin strip of Lauan plywood with concrete nails right into the concrete, so the rug could be fastened to that strip of plywood. I tried that but some nails bent over and others are not holding, and some are breaking up the concrete. Now what can I do?

K.C.Brookline

A. The secret to driving concrete nails into concrete is to use a heavy hammer, such as a mason's hammer. Heavy blows will drive such nails, but yours may be breaking up the concrete because they are too close to the edges of the concrete next to the hearth.

Have the installer glue the carpet in front of the hearth. Or put down the plywood lauan with construction adhesive.

Q. I am putting a rug on my basement concrete floor, using wall-to-wall indoor-outdoor carpeting, as you suggested. I went to the rug store, where they call the carpeting ``commercial.'' Is it the same as indoor-outdoor? What kind of pad is recommended?

JIM FRECHETTE, Quincy

A. Yes, as long as it breathes; that is, allows water vapor to go through it. As for the pad, a synthetic jute (or its equivalent) is recommended. It, too, allows water vapor to go through it. As long as water vapor that is coming up through the concrete can escape through the pad and the carpet, to be vented away, you'll be in good shape.

Rug stains
The saga of the mysterious black marks on Roberta Segel's white rug is over, solved by Segel's dogged determination.

This is what happened: Segel kept getting black marks on the rug under the folding doors of a closet, right where the hinges were when the doors were opened. She and the handyman thought that somehow black stuff was being scraped off the hinges as the doors were opened and deposited on the white rug. The handyman has several ideas, but nothing specific. Segel even replaced the hinges with new ones, but without success.

Finally she called Stanley Tools in New Britain, Conn., makers of the hinges, and lo and behold, Stanley determined that the hinges were defective and sent her a new batch of hinges and installed them for free.

It's a good ending to a frustrating problem. It's interesting, too; the handyman cut his teeth as a newspaperman in New Britain.

Q. I have a funny (well, not so funny) situation with my beige Berber rug. I am finding dusty green spots that appear here and there on the carpet, including in a closet under the shoe racks. You really have to look twice to see that it is a green color, and it does vacuum up readily without a trace remaining. It is not tracked in from the garden, and it is a complete mystery to me. The rug is about a year old. Could it be something coming out of the rug, which I think is some sort of synthetic?

ELLEN FARLEY, Rehoboth

A. Oh-oh, another stumper. Beats the heck out of the handyman, who applied all his available information to the problem and came up with zilch. Not even a good guess, so it's time to throw it out to the readers, who have in the past responded nicely to the handyman's funny questions. Does anyone out there know what the heck is going on? The handyman will take any and all suggestions, whether they are the true poop or wild guesses.

Rug stains
Well, Roberta Segel of Wayland is still having problems with black stains on a rug from the hinges of a bifold closet door. The stains are black, and are directly under the hinges when the door is open. The rug is white.

When she first told us about it, we were stumped; all we could think of is that somehow the hinges were scraping in their fixed pins as they moved, loosening small bits of metal that appear black on the carpet where they fell. The hinges were not treated with graphite, Segel said. She added that she cleaned the hinges, even had them replaced with new ones. Obviously, the stains are worse on the rug under the doors opened most frequently.

Hmm. One thing that comes to mind is that the white rug shows the stains more than, say, on an Oriental or dark rug with a pattern.

So, one again into the breach, rides the handyman. Perhaps a little WD40 sprayed on the hinges will make then work more smoothly, without as much scraping. Or, use white graphite. Even these tricks might not work because these materials can get dirty, and if they drop on the carpet, they will definitely show.

Hinges on bifold doors are usually brass-plated steel, which should not emit anything that would stain a rug. A vague possibility: If by any chance the hinges are aluminum, they could rub off a black color some way or another. We all know how our hands get black when we handle aluminum.

These may be lame answers, so the handyman tosses the question to readers who might have had similar problems and possibly a solution, and who are willing to share their successes.

Any ideas?

Q. Bleach was dropped on a royal blue nylon carpet. I tried dying it with Rit, but it came out a purplish tinge. The store suggested cutting out the bleached area and putting in a patch. What should I do?

R.P., Framingham

A. It's worth trying the patch. With many carpets today, such a patch can be almost invisible. No reflection on Rit, but the only other way to go is to dye the entire carpet by a professional. They're in the Yellow Pages under ``Carpet & Rug Dyers.'' Try a patch first. It is less expensive than dyeing, and if it doesn't work, you haven't lost much.

Q. A rug installer said he would glue down indoor-outdoor carpet on a concrete basement floor, covering the entire surface as a vapor barrier. Would this work?

R.R., Canton

A. Not in the handyman's opinion, because the glue is unlikely to be a vapor barrier, and even if it is, is unlikely to keep water vapor from coming up through the concrete and pushing off the glue layer. If the glue is a vapor barrier, it would defeat the purpose of the carpeting, which is designed to allow water vapor to go through it, into the room, where it can be ventilated away. The standard procedure, and I think the correct one, is to glue down only the edges, or secure the edges with nailing strips.

Q. I have a 12-foot-wide roll of old carpeting. Can I hang it from two pieces of rope in a carport?

VICTORIA, Abington

A. Sure, but the roll will sag at both ends and in the middle, making sort of an undulating snake; if left that way too long, the warping is likely to be permanent, or the very devil to straighten out. Use instead a thick wood dowel or a carpet tube, a heavy-duty cardboard tube. And hang the dowel, not the carpet. That is, the dowel should stick out a few inches at each end; then put your rope on the dowel ends instead of the carpet.

Q. Is there any carpet underpadding that has R value for insulation? What R value does carpet and padding have?

E.V. LUNDSTEDT, Marblehead

A. Carpeting and pads generally have similar R values, but not much: maybe 1 for both layers. If you can find a Homasote Carpet Underlayment, a rigid board 1/2- or 5/8-inch thick sold in building supply stores, this would provide a little more R value, maybe up to 2, with carpet. And, with this carpet underlayment, you don't need a pad. All this is for wall-to-wall carpeting.

Q. My house has wood parquet flooring tiles on a concrete slab. I'd like to put down carpeting, and I prefer Berber carpeting. Would that work over the tiles on concrete?

RICHARD SWIDELL, North Andover

A. It should work, but make sure that the Berber is breathable; that is, allows water vapor coming up through the concrete to continue through the rug and into the room. If it is not breathable, you could get water vapor trapped under the rug; if it condenses, you could have water under the rug. If the Berber is not breathable, you would be better off with indoor-outdoor carpeting, which is somewhat prosaic but breathable.