Q: I recently purchased a large poster printed on heavy paper stock, and I want to hang it on my wall. Since I live in an apartment, I don't want to use anything that will permanently mar the plaster wall surface. What do you suggest that I use?

A: The usual way to solve a problem of this kind is first to mount the poster on a piece of hardboard or plywood cut to the size of the poster. You can do this with ordinary white glue thinned about 20 percent with water. The mounted poster can then be hung like a large picture, with nails, screws, or picture-hanging hooks -- and you will be able to take it with you when you move.

Q: I have a problem with rust forming on a metal railing that surrounds the concrete deck over my garage. When the railing was installed about six years ago, I painted it with a well-known brand of paint that is made to protect iron. In spite of this, every year I have to wire-brush the rust off and repaint the railing. How can I eliminate, or at least slow down, this problem?

A: Although you used the right type of metal paint when you first installed the railing, and I assume you have used the same type every year since then, chances are you didn't do a proper job of coating all sides of the metal. This means bottom and top edges, corners that are hard to reach, and even inside joints where two pieces are fastened together.

If all sides are not coated, rust will form where you cannot see it, then spread under the paint to other places until it pushes the paint off from underneath. Scraping back to bare metal, then coating all sides is the only answer, even if you have to disassemble parts of the railing to get the job done.

Q: I have a home in the country that we do not use in the winter. I cut the water off and open all the faucets at the end of the summer, but this is aparently not enough to eliminate all problems with pipes cracking. What else should I do?

A: Opening the faucets does not necessarily empty all the pipes, because water remains in low spots between faucets and in pipes in the basement or under the lowest faucet. You will have to open a fitting (or install one that can be opened in the winter) at the lowest point or points in the system -- including near the water heater. Also, don't forget to drain the waste system -- water stands in the traps and can freeze. These should be filled with anti-freeze solution (half and half with water) to keep them from freezing.

Q: The basement floor of my brownstone house is bumpy and broken in many places, and after a spring thaw, water sometimes flows up through the cracks. I would like to level and repair this floor, but no one seems to be able to tell me the easiest way to do this. What do you suggest?

A: It is not simple, but is probably the only solution: You will have to break up the old concrete and pour a new concrete floor on top of it -- or in place of it after you remove the pieces from the old floor. You may also have to install drains (perforated drainpipe) around the perimeter to relieve the pressure if the water condition in the ground is serious.

Q: I have a kitchen counter top that has numerous marks and cuts in the plastic. I don't want to buy a whole new counter top. It has a splashboard at the back, but only the horizontal portion looks bad. Can you tell me what I can cover this with so I don't have to buy a whole new top?

A: You can cover it with another layer of plastic laminate similar to the type you now have. You will have to clean the old surface by scrubbing it thoroughly then sanding it with medium-grit paper to roughen it slightly. Use contact cement to put the new plastic down on top of the old. This may involve some fitting problems around the edges where new moldings may be needed, or where you may have to remove and then replace the original ones. Also, the sink may have to be taken out and reset if the plastic has to fit under its rim.

Q: I have a stall shower with walls of galvanized metal. It has been painted over and over for years, and most recently has been done with an expensive epoxy paint. Yet after a month or two the walls and cement floor turn black and spotty. What can I do to improve this situation?

A: The black spots are probably mildew and have nothing to do with the quality of the paint. They should wash off with a solution of part Clorox and three parts water. Scrub on, allow to dry, then flush off with water. When you repaint, add some extra mildewcide to the paint to minimize the problem. Also, install an exhaust fan in the bathroom to provide more ventilation.

Q: I recently moved into a new house that has a wood deck outside. This is coated with one thin layer of paint. How do I weather-proof this wood deck, and do I have to strip the paint off first to do it?

A: By "weatherproof," I assume you mean protect the wood and seal it against weathering. The best way is to coat the wood liberally with clear wood preservative or stain -- but this can be applied only to unpainted wood. The paint will have to be sanded off or stripped off with paint remover -- or you can wait a year or two until it all peels and weathers off. The preservative should be applied to the bottom and edges of each board, but if this is not practical, coat as much as you can reach.