Question - A brass memorial plaque in a medium-size stone has come loose. The stone was carved to provide a flat surface for the plaque to set properly. There's a hole in each corner for bolts, but the plaque was originally glued. Is there a strong, weatherproof glue I can use to make a permanent bond? Bill Fallon, Arlington, Mass.

Answer - Yes. Use construction adhesive. Liquid Nails is one good brand that comes in a caulking cartridge. Draw a bead of this close to the border of the plaque, but not so close that it will ooze beyond the edges when you set the plaque in place. Also, make a generous "X" of the adhesive from corner to corner. Place the plaque, hold it for a few minutes and you're done. It is weatherproof and resistant to expansion and contraction with heat and cold. I have held a broken outdoor brick together with this stuff for 20 years. Polyseamseal vinyl adhesive caulk also will work.

You said the plaque has a hole in each corner for attaching it with bolts. You could do that too, but you'd have to be careful in drilling holes in a relatively small stone. If you do, I suggest you have the holes drilled by a monument man; the stone may be granite, which is hard and dense, and drilling could split the stone if it is not done correctly. If you opt for the holes and bolts, use brass bolts or screws, and insert an expandable sleeve in the hole before driving the bolts or screws home. If the stone is sandstone or limestone, you could probably drill the holes yourself with a masonry bit on a variable-speed drill. Slow and easy does it.

Question - We had new shingles put on half of the front of our house to match the old, but now I think the wrong kind of shingles were used. The original shingles were exposed 73/4 inches, and we were told that we used white cedar shingles instead of red cedar shingles. Since the white cedar shingles are only 16 inches long, we were told they are too short for proper overlap; the red cedar shingles are 18 inches long and give the proper overlap. Now what can we do? Mary Wolff, Arlington, Mass.

Answer - Not to worry, really. The short shingles exposed 73/4 inches will still provide an 81/4-inch overlap, enough to make the wall weathertight, especially if you applied Tyvek or roofing felt under them.

The only thing you have to be concerned about is that white cedar shingles exposed that much will tend to curl more than usual; curl from side to side as well as from the bottom up, which can be a problem. To avoid this, I suggest you drive a hot zinc-dipped galvanized shingle nail at the bottom of each shingle, 1 to 11/2 inches from the bottom and 1 inch from each side. This will hold them in place, and while such face-nailing is not normally done with shingles, it will prevent curling. You can paint or stain over the nails and no one except you will know the difference, and of course you will tell no one.

When nailing that close to the bottom and sides of a shingle, be careful not to split them. If you tend to split the shingle you can predrill small holes to take the nails.

Question - I have a question as well as an answer for you. The question is: My gas furnace and hot water heater share the same flue. I plan to put in a high-efficiency furnace that will be exhausted through a wall and not up the chimney. Would the hot water heater work all right since it will be the only appliance using the chimney? Will the draft be adequate? As for the answer, a good way to get rid of Japanese bamboo without rooting it out by brute force is to use Roundup. Mix 6 ounces of the concentrate with a gallon of water and paint or spray the leaves with this mixture. Repeat in two or three weeks. James P. Kartel, Andover, Mass.

Answer - Thanks for the answer, for starters. As for a shared flue, just one appliance on a flue should not be problem. Go ahead. In fact, it might work better because sometimes the units sharing a chimney will interfere with each other.

Question - You mentioned an asphalt tape that is sold to repair holes in gutters. It sounded like a great idea for the holes in my copper gutters, but I called what seemed like 50 places to locate the tape without success. Where can I get that tape? Herb Savits, Weston, Mass.

Answer - Here is one case where calling ahead is no help. I would lay odds that some of the big building supply dealers and hardware stores carry it. It's a matter of checking on site.

But if you can't find the tape, here's a good substitute that will last just as long, and will work with gutters of any material, just as the tape will work with any material. Cover the holes with roofing cement, then embed heavy aluminum foil in the cement; add another layer of roofing cement if you like.

If the holes are so big that the roofing cement oozes out of them (and it will in hot weather), put a small piece of foil or copper disc over each hole before putting on the roofing cement. In fact, a penny over each hole will do nicely. Or, drive a short, copper sheet-metal screw into each hole, from the outside in. Copper screws may be hard or impossible to find, but I am reluctant to suggest any other metal because non-copper screws could cause a galvanic action that could corrode the copper and make the holes bigger.

Question - My roofer would like to put a rubber roof over the shingles of my Cape-style house, where the dormer makes the roof quite shallow. He said he would put a rigid material over the shingles before laying down the rubber roof. Would this be OK? Lila Daman, Concord, Mass.

Answer - Yes, it is OK, because a rubber roof should go over bare wood sheathing or that rigid material the roofer mentioned, but not directly on old roll roofing or shingles. I think it would be better to take everything off to the bare wood sheathing (more expensive, perhaps), because the added thickness of the rigid material and rubber roof will present prob-lems at edges. If the roofer can make the edges look good, especially along the rake (where the edge of the roof meets the side of the house), then go ahead.