R.B., Foxborough

A. Call an architect, and, if possible, the architect who designed the house.

Vertical siding (presumably wood boards with battens covering the joints or the reverse of that, boards covering the battens), with all those vertical seams and joints, is not an ideal siding, particularly in wet or harsh climates. Too often houses designed in Southern California simply do not work very well in New England.

Particulary suspect are the casings that are flush with the vertical siding, creating perfect conduits for water to enter at a window above the dining room, creating the ceilings leaks. If there is flashing above those windows, that is good, and often solves the problem. There may be good flashing at the sides of the windows as well, but vertical joints or seams are difficult to flash properly. If the vertical joints are not flashed, you can caulk until you're blue in the face without success. If the vertical siding acts as sheathing as well, the situation is aggravated.

Hope that the architect won't throw up his hands in frustration.

Q. The caulking around the soil pipe failed where it comes up through the roof, so the ceiling below cracked and sagged. How can I fix the ceiling? It is in a small bathroom.

E.R., Needham

A. I suggest taking down the entire ceiling, putting up plasterboard (a so-called dry wall) and applying two coats of white latex ceiling paint. Or, use Greenboard as a more waterproof dry wall. Or, to get fancy, apply Blueboard and have it skimcoated. Ordinary dry wall and paint will work as well as anything.

Of course, I hope you had the leak fixed. You mentioned caulking around the soil pipe where it comes up through the roof. If it were just caulking, it will never stay leakproof.

Flashing sleeves are made for soil pipes. Measure the diameter of your pipe and buy a sleeve to fit it. The sleeve is a rubber doughnut with an aluminum flashing flange.

Q. I like the idea of insulating the ceiling of my crawl space to help make the floors above warmer. Someone said it was a bad idea; that it would trap insects and moisture. Isn't the ceiling a haven for insects and moisture anyway?

KEVIN CONNOLLY, Arlington

A. A crawl space, unventilated and unscreened, is likely to harbor insects and moisture, which can be dealt with another way, after you install the insulation, which is definitely the way to go. It will reduce heat loss into the crawl space.

After you do that you are not through. You must ventilate the crawl space by keeping windows (if any) or other vents open from April to November. In winter, venting is not necessary because there is less moisture in the crawl space. Also, put polyethylene plastic on the ground; it will help keep water vapor there, where it belongs. If you have no windows or vents, install some to allow cross-ventilation, which will release any water vapor that gets in. Most ``insects'' in such crawl spaces are spiders (technically not insects), which are beneficial because they eat bugs.

Q. My house was built three years ago, with a huge room with a cathedral ceiling, open end to end. When cracks appeared in the ceiling, a painter patched them, but they look worse than before. An engineer said the cracks were from stress and settling, and suggested $25,000 to shore up the foundation. Do I really have to do that? Besides, how can I patch those cracks so they will not show?

DMITRI HOMSY, Canton

A. From what the engineer suggests, your house is defective and the builder should be brought to task. I would get a second opinion concerning the foundation. There is another possible cause of the cracks in addition to settling and stress, not necessarily due to a faulty foundation. A large room with cathedral ceiling open end to end is not always stable, and is subject to excessive stress.

So, consider installing collar ties to connect the two slopes of the cathedral ceiling. Collar tiles are commonly found in attics under a gabled roof; the rafters form an upside-down ``V,'' and the collar ties turn that upside-down ``V'' into an ``A.'' If you feel that collar ties will spoil the aesthetics, then live with the cracks.

Finally, you can fill the cracks with caulking: Press it in with your fingers, smooth off and paint, if necessary. The caulking will expand and contract with the movement of the ceiling, and should stay in the cracks.

Q. My unfinished basement has fiberglass insulation in the ceiling. I am concerned about invisible shards of glass sloughing off the fiberglass and getting into the air I breathe. What can I put over it to prevent this? And whatever I put up, does it have to come down if and when I install a regular ceiling?

BILL MUMFORD, Lakeville

A. Staple Tyvek or similar material to the ceiling joists. It is an air stop but not a vapor stop, and while it is not designed to go on a crawl space ceiling, it is what you need there. It will not only help reduce heat loss into the basement, but is white, reflecting what little light there is in the basement. You can keep it up when you finish the ceiling.

Q. My attic ceiling tiles have a lot of water stains. How can I cover them? I heard I could get rid of them with bleach and water.

K.M., Milton

A. Some people have had luck with bleach and water in removing water stains. But, even if this works, they may come back. Besides, the tiles are fibrous and might react adversely to the bleach. It is better, in my opinion and my experience, to seal in those stains with clear shellac, then repaint the ceiling. You could try repainting just the affected tiles after using the clear shellac, but that way you would probably never get any two tiles to match.

Q. I am replacing the ceiling tiles in my bathroom. I found the flat, smooth, painted tiles you mentioned that are washable (as opposed to acoustical tiles with holes or fissures), but the people at Home Depot said the tiles will not hold onto the ceiling in a damp environment. I am concerned about that because part of the ceiling is over a tub shower. Will the tiles work in that area, and more important, will they hold?

ED TAKACH, Arlington

A. Nothing much of anything will stick well on a damp surface, but you should be able to put up the tiles with adhesive if the surfaces are dry, because most adhesives for ceiling tiles are water resistant, and are generally unbothered by moisture. And, if you are reluctant to use adhesive, you could install 1-by-3-inch strapping to the ceiling, then staple the new tiles to that strapping.

And, while you are at it, consider putting in an exhaust fan. Properly used, this fan will keep the bathroom as dry as it ever will be.

Q. I put a 5-inch-wide hole in my ceiling when I redid a room, removing the old plaster and wood lath. The ceiling looks and feels like concrete. How can I fill that hole?

DAN McLAUGHLIN, Brighton

A. If the ceiling looks and feels like concrete, it probably is. If you can see wire lath in the hole, simply fill it with mortar; you may have to put in more than one layer. When you get the mortar nearly level with the ceiling, or a little below it, wait 15 minutes then rub with a wood float (a wood or hard foam-faced trowel), or a rough piece of wood. This should match the current ceiling. You can buy Sacrete or Quickcrete mortar mix at lumber stores.

If there is no wire lath, you can staple some onto any joist that shows. If no joist is showing, make the hole bigger to expose at least one joist and staple wire lath or hardware cloth ( 1/4-inch steel mesh); this lath or mesh will hold the mortar in place.

If the ceiling is plaster and not mortar, you could do the same with the wire lath or hardware cloth and fill the hole with spackling compound, patching plaster, or joint compound. If the hole is more than 1/2-inch deep, you should apply the plaster in thin layers. If you don't do this, the patch will crack and fail quickly. Apply the plaster about 1/4-inch thick for starters, and as it sets up, score it with a fork or the point of a trowel. This scoring will allow the next coat to stick better.

To match the scroll or design of the ceiling, paint it with a texture paint and make the scrolls with a stiff, dry brush. For a stucco look, press a sponge in the wet paint.

Q. My kitchen ceiling is rough-sawn cedar boards that are stained with a color stain. A bathroom leak above the kitchen stained the ceiling with water marks. What can I do?

C.L., Reading

A. Sand the water marks to try to reduce them and restain the ceiling. If the ceiling is only stained by that color stain and not varnished, you can restain only the places you sanded. Other than that, the stains may be there to stay.

Q. My bathroom ceiling is peeling forever, and I am tired of trying to paint it and repaint it. What can I cover it with that will be relatively permanent and relatively maintenance free? Can I use some sort of acoustical tile, or a vinyl cloth wallpaper?

LEONARD CHAPMAN, Dorchester

A. Tiles of some sort would be acceptable, but they don't have to be acoustical, unless you have an unusual noise problem in the bathroom: singing Pagliacci in the shower, perhaps? Actually, a smooth, washable tile would be best. The handyman's tiles in one bathroom have given yeoman service for years. But first you have to remove as much of the peeling paint as possible. In fact, you have to remove as much of the paint no matter what you apply. Then glue the tiles, which are tongued and grooved, using construction adhesive, a dab in each corner and one in the middle of each tile. The prepainted tiles will last for years, and can be repainted when necessary. Vinyl cloth wallpaper (a Wall-Tex type, which is vinyl-coated canvas) might also work, but if there is excessive moisture in the bathroom, it could come loose. If the room is not too big, you can apply shiny, white laminated plastic, cut to fit the ceiling and applied with contact cement or an adhesive caulk. The plastic will not peel, and being smooth and shiny, will resist mold. I suggest you also install an exhaust fan to eliminate water vapor created by showering. The fan should exhaust to the outdoors, not into the attic or anywhere in the house.

Q. A building near me is up for auction, an old pharmacy with a tin ceiling. I am interested in that ceiling; can a tin ceiling be taken down in once piece, intact? Can it be taken down any way, intact?

A.B., Brighton

A. I believe all tin ceilings, even old ones, are put up in sections, usually one by one foot or one by two feet; some may be 16 inches wide so they can be applied to ceiling joists or strapping 16 inches on center. No matter the size of tiles, you need great care to remove them because if bent, and being heavily embossed, they are virtually impossible to straighten out. You should be able to see where they have been been nailed, because tin ceiling tiles are overlapped as they are applied. Try to pull these nails, which will make the tiles more easily removed without bending. And if you have to pry off a tile, try prying where a nail is; there will be less bending of the tile and the nails can be removed. If you succeed, and put up the tiles in their new location, you will probably have to paint them. Wire-brush any loose paint, wash with a strong solution of Spic and Span and water, and let dry thoroughly and quickly. Paint with an oil-based primer and finish coat; do not use latex, which can cause rust spots.

Q. I discovered too late that my entry ceiling is calcimine. The ceiling paint I put up came right off on the roller. Can I put up something that will work with calcimine? The new paint refused to stick, so I don't think there is any on the ceiling. Do I have to take it off? How?

MARION LENT, Newton Center

A. It's an old story, reprinted here because it has not been mentioned in some time. Your experience is a classic calcimine problem. Calcimine was used years ago as a ceiling paint because it was inexpensive and stayed white. Trouble is, it was not compatible with any other paints, oil, or latex. Since you feel there is nothing on the ceiling now but calcimine, you can buy a paint called Kal-Kote or Kal-Koter that is compatible with calcimine. If that works, fine. If it doesn't, then you have to remove every trace of the calcimine before applying regular latex ceiling paint. Taking off calcimine is another story. One treatment is to apply a coat of wheat- or cellulose-based wallpaper paste, and wait; with luck, the next day the paste and the calcimine will be on the floor. The paste shrinks as it dries, pulling the calcimine right off. The only other way is to wash the calcimine with Spic and Span and water, to soften the calcimine so you could scrape it off with a wide putty knife. Rewash until the calcimine is gone; you can tell that when your sponge does not come out a solid white when you wash.

Q. Each tile of the acoustic ceiling in my sunroom is held up by four dawbs of adhesive. The tiles come off easily enough, but those dawbs of adhesive are sticking to the plasterboard ceiling like crazy. I tried chipping without success. How can I remove those dawbs?

PHILIP ROSSETTI, Arlington

A. I am reluctant to suggest heat, because of the possibility that the adhesive is flammable. But you could chip off a piece and see if it burns; if it does not, then you can use heat to soften it, but use a hair dryer, not a hot-air gun; the latter is much too hot to use indoors. This should soften it enough so that it can be scraped off. Or, chemical paint remover may make short work of it.

Q. I am insulating the ceiling of my crawl space that has an earth floor. I am getting conflicting advice on where the vapor barrier (paper backing of the insulation) should face: One contractor said it should face the ceiling (the floor above), another said it should face down, on the crawl-space side. What should I do?

E.E., Sudbury

A. Follow the standard rule with insulation: The vapor barrier always faces the warm part of the house, so it should go up, touching the floorsboards above. You may have no trouble if you do it the other way, but there is always the possibility of trapping moisture between the paper and the floor. Contractors sometimes install insulation with the paper down because it is easier.

Also, cover the earth floor with polyethylene plastic, to prevent water vapor from coming up through the earth, which it is sure to do without that plastic, even if the earth feels dry. Finally, ventilate that crawl space from spring to autumn. Winter ventilation is not necessary, so you can close the vents to keep the crawl space from getting colder than necessary.

Q. I have funny yellow spots on some of the acoustical panels in my dropped ceiling. What are they and how can I get rid of them?

ELIZABETH CONARD, Wayland

A. The yellow spots sound like water marks; those fibrous acoustical tiles are notorious for staining from water. First, make sure there are no leaks above that suspended ceiling. Even a small amount of water, such as condensation on a water pipe (not a leak) dripping from the pipe to the inside of the panel, could cause the spots. If you can determine that, wrap pipe insulation around the pipe to prevent the condensation.

To get rid of the spots, apply a mix of 1 part liquid chlorine bleach and 3 parts water. If the spots disappear, fine; straight bleach might make them yellower. If that doesn't work, rinse off the bleach, let dry, and apply one coat of clear shellac; then paint the panel or the whole ceiling. The shellac is to prevent the bleeding of those spots through the paint. Of course, wear skin and eye protection when working with bleach.

Acoustical panels, especially the ones with holes rather than fissures, are difficult to paint because the paint often fills the holes randomly. You can always open the hole with a small dowel, but it is tedious. If all this fails, you can replace the spotted panels with a panel similar to or just like the old one. They are sold at building stores.

Q. I am having a Blueboard ceiling installed in the dining room, over the old ceiling that is in bad shape, then a skimcoat. Is the added weight of the Blueboard and skimcoat a problem?

P.M., Watertown

A. If the Blueboard is screwed to the strapping, which is under the old ceiling, and the strapping (1-by-3-inch boards) is tightly nailed to the joists, weight is not a problem. In fact, the Blueboard screwed to the strapping is the only way it will stay up.

Q. I saw your story Sunday about a suspended ceiling system that uses a grid that is very close to the ceiling joists instead of hanging down several inches. That's just what I need. Who makes them and where can I find them?

CHISUN LIN, Winchester

A. I believe Armstrong makes them; in fact, I remember much ballyhoo when the system was introduced. Check Home Depot or other lumber dealers that sell suspended ceilings. Such a system was developed for basement ceilings, where the overhead is low.

Q. My Christmas tree was too high for the house, as usual, and when I put it up and took it down, the top scratched the ceiling, making an 8-inch-long brown stain. A friend suggested applying bleach. Is there anything else I should or shouldn't do?

MARK McKIE, Reading

A. I don't think bleach will work because the stain was made by the wood, but it won't hurt to try. Another thing to try is a strong solution of detergent and water. These treatments may reduce the stain, but not the scratch. Your last resort is to smooth out the scratch and paint it with two thin coats of a latex ceiling paint. If the new paint makes sort of a patch on the ceiling, then you will have to repaint the entire ceiling.

Q. There is frost on one side of my attic ceiling (the inside of the roof), and there is some mildew growing as well. The area is mostly above a pull-down attic stairway. The attic floor is insulated, and I have eave vents and a ridge vent. Obviously those vents are not doing their job of venting the attic, are they?

J.H., Westford

A. The vents are doing their job, but there's another reason why that particular area is frosty and mildewy. Moisture is escaping through the stairway hole and rising right up to the cold ceiling and condensing. This will happen even if the stairway is up in the closed position. These stairways are notorious for their ability to leak air. The ``door'' in the opening would be like your front door, if your front door were uninsulated, unweatherstripped and without a storm door.

Correcting this situation is relatively easy. Seal the opening and insulate it at the same time. Build a wall on the attic floor around the opening, using 2-by-6-inch or 2-by-8 pieces of wood. This little wall is mainly to keep the cover above the stairway when it is folded up, in the closed position. Now, build a box of 1-by-6s to cover the opening. Nail quarter-inch plywood or hardboard on the bottom, fill it with insulation and attach a cover of eighth-inch hardboard. Put weatherstripping around the opening, like a gasket, so that when the box is set on top of it, it will seal it. Make sure the box is heavy enough to press down on the weatherstripping. You could hinge the box to the 2-by-6-inch wall to make it easy to open when you go into the attic.

This is one way to seal that opening, and provide insulation to reduce loss of heat. There are other ways to build a box. It can be thinner, filled with 3 inches of Styrofoam insulation or other foam insulation, such as Thermax. The 3 inches will provide an R value of 15 to 21, depending on the insulation used. If you use either of these foams, the box must be covered because the insulation is flammable.

Q. I am washing and painting the panels in my dropped kitchen ceiling, which is no problem. But the metal grids holding the panels are a problem -- dirty and rusty. How can I clean up those grids?

G.B., Concord

A. You might be able to clean off the rust with soap pads. If not, sand off every trace of rust, sand, clean with detergent and water, wiping dry so the water will not cause more rust. Or, clean with paint thinner; the thinner will not encourage more rust. Paint with an oil-based primer and finish off with a gloss or semigloss, oil-based enamel.

Or you might be able to find anodized aluminum grids to replace those steel ones. The aluminum will not rust.

Q. When we moved into a 1942 Colonial house two years ago we noticed a fine crack on the ceiling, going from the living room across the stairway hall and into the dining room, about 6 feet from the front of the house. The building inspector said it was no problem.

Now, it is bigger, and appears to be getting bigger. What can we do?

MICHAEL LYONS, Norwood

A. It sounds as if there is a fair span across that hallway, which typically holds the stairway and a hall leading to the back of the house, even longer if the stairway is exposed in the living room or dining room. The joists may be sagging, enlarging the crack. The crack, 6 feet back of the front wall of the house, indicates it is directly over the first step of the stairway.

Walking on the floor above that area may also be causing the enlargement. To determine that, walk on the second floor above the crack area, and see if the floor bounces.

If it does, replace the newel post of the stairway with a full-length post, supporting the joist above it. You may have to set a wood plate on the ceiling to make sure the post does support a joist, not the ceiling between joists.

Then again if you do nothing the crack might not become larger.

To fill the crack, put a bead of caulking compound on it, then press it into the crack with your finger. Scrape and wipe off excess. The compound will expand and contract with the movement of the crack and keep it filled.

One more cause of the crack could be expansion and contraction of the wood joists, due to moisture being taken in and expelled.

Q. I plan to install a new tin ceiling on two of my rooms. I plan to set up strapping as a nailing base. I have an automatic brad nailer; could I install the tin panels with that nailer? The tin panels have dimples where nails are supposed to go; would that brad nailer penetrate the tin?

P.B., West Roxbury

A. It's a good question, and the way to find out whether the nailer will penetrate the tin is to try it on one panel, not on the ceiling but on a workbench surface. The brads should have a head other than a finish-nail head; a finish-nail head will not hold the panels. And, the brads should be at least three-quarters of an inch long, maybe even an inch.

If the nailer brad will not penetrate those dimples, then you will have to make your own holes by hand driving a small nail through the dimples, or even drilling with a very thin bit.

Q. I have a suspended ceiling in a breezeway that gets no heat, and the 2-by-4-foot panels have absorbed moisture and have sagged. It will be easy to replace the panels, but is there a way to seal against the moisture?

B.C.A., Lynnfield

A. First, when you go to the panel store for replacements, buy weatherproof panels and don't be content with the clerk's word that they are weatherproof. Make sure. Or, paint standard panels with an oil-based exterior primer -- front and back sides and all edges. Paint the exposed side with a latex house paint, then install.

Or, cut 2-by-4-foot panels of half-inch exterior plywood, and prime and paint all sides and edges as you would the purchased panels.

Q. I am noticing dark shadowy marks on my ceilings. They are exactly where the beams would be. You can even make out the nail holes. Could the beams in my attic be rotting through? The house is about 20 years old, the paint is three years old. Who should I contact for repairs?

BARBARA McNALLY, Indianapolis

A. First off, your beams are not rotting through. There is nothing broken, so it doesn't need fixing. Those shadowy marks on the ceilings are mildew or dirt, and they are appearing where the beams actually are, or where the strapping is. Strapping is narrow boards nailed to the joists (beams); the ceiling finish (plasterboard or plaster or a skim-coat plaster) is applied to this strapping.

What's happening is this: The beams or strapping are cooler than the rest of the ceiling, above which is insulation. Water vapor builds up in the house and condenses into water on windows and, in your case, the ceiling under the beams or strapping. These damp areas (you may not even see the dampness) are a perfect place for mildew to grow. If it is not mildew, it is dirt, which clings to the damp areas more than it will cling to a dry area. The same applies to the showing of the nail heads on the ceiling, which are cooler than the rest of the ceiling despite being covered with plaster.

To determine if the marks are mildew, paint a small area with a mix of one part chlorine bleach and three parts water. If the marks disappear within 10 seconds, it is mildew, and you can use the bleach/water mix on the whole ceiling, or just on the shadows. Wear skin and eye protection when working with bleach.

If the marks do not disappear, it is dirt. Wash the ceiling with a solution of Spic and Span and water; add a cup of bleach to the wash water. If the ceiling cannot be washed (your picture showed a scrolled ceiling, which is miserable to wash), repaint it. If there is any mildew present, it must be killed by the bleach/water mix before painting. And that bleach/water mix must be rinsed off.

A way to prevent this condensation of moisture is to reduce the amount of moisture in the room and/or house, by ventilating regularly.

Q. My old house needs new ceilings in three rooms and a hall. I had three estimates: Onesaid he would put up dry wall directly to the old ceilings. Others said they would put up strapping before putting up the new ceiling. Which is best? The four ceilings would cost $1,900.

CLAIRE ADAMS, Chelmsford

A. First off, the cost is reasonable, amounting to $475 per room. There is no ``best'' in this case. Putting dry wall directly on the old ceiling is acceptable, as long as the new dry wall is attached to the old strapping above the old ceiling. The strapping technique actually is a little better, because a more level ceiling can be achieved, and this is important if the old ceilings are not level or even.

Q. A nice-looking cedar board ceiling adorns my sunroom, with lots of skylights and sliders. Right now it is bare cedar, and it really does look good. What can I put on that cedar, 1 x 6 tongued and grooved boards with a V groove, to preserve and protect it?

CHARLES DAME, Danvers

A. Nothing. The cedar will protect and preserve itself. It will darken with age over several years, but even clear-coated, it will darken. If the roof leaks, you may get some stains, but you could get those even with a clear coat.

The handyman has had such a ceiling on a screened porch for 15 years, and it is as good looking as when it was new 15 years ago. In fact, it looks so good that the handyman put the same boards on ceilings of three outdoor porches.

Q. I am buying a house with beautiful tin ceilings, but I think they are painted with lead paint. How can I remove that paint safely?

CARL PAULSEN, Portsmouth, N.H.

A. If there are children in the house, you have to remove the paint. But it's a good idea anyway because if it is peeling you may be getting bits of leaded paint fluttering down every now and then. Not healthful, even for an adult.

First, have a paint chip analyzed to confirm that it is lead. If it is, I think your best bet is to carefully remove the panels, if they are panels (and they usually are) of different sizes, nailed to strapping. They should come down fairly easily, but be careful not to bend them, because it is difficult to bend them back to the right shape. Then, use a non-methylene chloride paint remover. If you can do this outside, all the better.

Repaint the panels before reinstalling them. Prime with an oil-based primer and finish with an oil-based ceiling paint. You want to use oil-based paints to prevent rusting.

Ceilings seem to be the bane of many homeowners' existence, but here's one homeowner who obviously did everything right. Alex Carson of Chelmsford had calcimine ceilings, which can be a pain from the start.

Carson told us what he did: ``I scraped off the calcimine with a razor-blade scraper. It came off quite easily. Then I washed with Spic and Span. Then I painted with one coat of a latex enamel undercoater and another coat of ceiling paint. It worked wonderfully, and is still working.''

Which goes to show that proper treatment and a little luck are keys to success, whether you have peeling ceilings or calcimine. Actually, Carson did what the handyman would have suggested, and does to many callers.

Some day the handyman is going to make a million dollars with this idea: Movable ceilings, so you can lower the ceiling in order to work on it in comfort, then put it back up. Impossible? Maybe not, but expensive. One could devise a movable ceiling that rolls into place and rolls down when needed, a little like an overhead garage door. Think about it.

Q. I read your reference to hard, smooth ceiling tiles, to cover an old, peeling bathroom ceiling, which you said are easy to keep clean. I looked around and found nothing like that. What are you talking about?

DAVID HELMER, New Orleans, La.

A. I am talking about ceiling tiles that are hard (not soft as many fiber tiles), smooth (not acoustic tiles, those with holes or fissures). They come 12 by 12 inches, sometimes 12 by 24 inches, and can be put up with adhesive. They are sold in lumber and building supply stores; even the chains like Home Depot should carry them. Armstrong, a big name in ceiling tiles, makes them, among others.

I put them in one of my bathrooms years ago; they not only are hard and smooth and washable, but the paint, which gives the tiles their hardness, does not peel.

Q. I tried to put Formica on the ceiling of a shower alcove using Weldwood cement, but it didn't stick. What can I use?

R.S., Needham

A. The Handyman has suggested laminated plastic for shower ceilings, even whole bathroom ceilings, to solve the perennial problem of peeling paint. It's a good way to go, but if it doesn't stick, all is lost.

Well, all is not necessarily lost, because it can be done. Is the Weldwood cement you mentioned a contact cement? If so, it should have worked, but you have to put it on both the ceiling and the plastic. If you did that, then I am guessing that the cement was absorbed by the soft plaster or plasterboard, which would make it fail. Or, there was too much peeling paint on the ceiling. So, instead of trying new contact cement, I suggest you put it up with phenolic vinyl adhesive caulk. The brand name is Phenoseal, and boy, does it ever hold. Draw a bead of caulk on the ceiling in the shape of an X, and then a couple of squares near the border and toward the middle. You may have to hold it in place for a few minutes because the caulk takes a little while to set, and to hold. Or, use construction adhesive, which, like the caulk, comes in a caulking cartridge, making it quite easy to use. Liquid Nails is one brand.

If there is a lot of peeling paint on the ceiling, scrape and sand as much of it off as practicable.

Q. I have several ceiling medallions in my Victorian house, made of plaster and nice looking. They have been painted a million times, and now I wonder how I can remove all that paint to reveal the attractive detail.

MARGARET SANFILIPPO, Somerville

A. The medallions are called anaglyphs (from the Greek words to carve), and they are indeed handsome. Remove the paint with chemical paint remover. Apply the remover, wait 15 minutes, and scrape off bubbling paint with a narrow putty knife. Repeat as necessary. Use a putty knife with rounded corners to prevent gouging the plaster, which will be unaffected by the remover.

As you remove more layers of paint, you can apply one last coat and rub it off with coarse steel wool. Use lots of ventilation when working with the remover. Standard removers are good but toxic and caustic; Citristrip, a citrus-based remover, is milder but possibly slower working. Don't use a hot-air gun; it is a fire hazard indoors and does not work well on plaster.

Q. My dining room ceiling is scrolled, and it's peeling. The advice I received was to apply a coat of BIN after scraping off the peeling paint. But the BIN is now peeling off, too. What can I do to prevent the peeling?

ANNE HILTON, South Weymouth

A. BIN is a good stain killer where needed but not much of primer or sealer. Now you have to try to scrape and brush off the peeling paint with a medium-stiff bristle brush. Those scrolled ceilings are a pain when the paint peels because removing the paint is difficult. With the paint scraped, brushed, or sanded off, wash the ceiling with a strong solution of detergent and water, then let dry.

Apply a thin coat of a latex enamel undercoater. Normally, this is not needed on plaster but because of your previous peeling experience it is a good idea here, since such undercoaters stick to a lot of surfaces. Then apply two thin coats of latex ceiling paint. Notice that I suggest thin coats; thick coats are much more likely to peel.

Q. My 30-year-old house had settlement cracks in a ceiling and a wall recently. I applied joint compound and paper tape, to prevent them from recurring. Well, they did, cracking right through the tape. I'd like to retape, but should I dig out the cracks to be a little wider than the hairlines there now? Is there an alternative?

JOE CRIVELLO, Duxbury

A. If cracks appeared within the last few years, they are not from settlement, because the house has done all the settling within a few years of its building. The cracks are from expansion and contraction of the wall and ceiling as they gain and lose moisture.

If you retape, remove the old tape and compund and open the cracks 1/8 to 1/4 inch wide, and as deep as the plasterboard. Apply a self-adhesive nylon mesh tape of the type used when Blueboard is skimcoated. Then fill the crack with joint compound, pressing right through the tape, and spread it thinly on each side; this will allow the compound to key into the crack rather than sitting on the surface. Apply a thin coat over the tape, and after that dries, apply two more thin layers of compound, letting it dry between coats. Sand and repaint.

Nylon mesh tape is designed to resist the stress of expanding and contracting materials.

Or, try this easier method, which might work as well or better. Remove the tape and old compound. Buy PhenoSeal, a flexible adhesive caulk in a caulking cartridge. Run a bead of this on the crack and press it in with your fingers. This flexible caulk is the only thing that can be forced into a hairline crack; you could widen it a bit, but that might not be necessary. Scrape off excess with a putty knife and clean residue with a wet sponge. The caulk will expand and contract with the movement of the wall/ceiling and keep the crack from reappearing.