Q: I have a white marble top that broke in half. Is there any way the two pieces of marble can be fastened back together?

A: Marble can be joined permanently with a two-part epoxy adhesive. If the two pieces are just glued edge-to-edge they will hold, assuming the marble is resting on top of a support such as wood or plywood. If the marble is only supported at the ends, the joint may or may not take the strain when someone leans on it, or when a heavy weight is placed on top. It depends on how wide and heavy the marble is, and on how good a joint you get. Epoxies come in various colors, so try to get a white or clear one so the joint will be less noticeable. You will see the repaired crack or break, no matter what color you use.

Q: During a heavy rain, water pouring off the roof runs into a basement window well and through two gaps above ground level where the metal sides of the window well do not quite meet the concrete block foundation. The gaps are up to 2 inches wide and extend 8 inches from the ground to the top of the wall. What do you recommend for filling these gaps?

A: You can close those gaps in one of two ways. One way is to build a temporary form of wood or metal and pour concrete into the opening. Be sure to rough up the old concrete foundation first so you get a good bond between the old and new materials. The second way is to erect a barrier of sheet metal - aluminum or galvanized steel - fastening it to the window well with bolts or screws, and to the concrete with achor plugs. Then cover the joints with butyl rubber or silicone rubber caulking compound.

Q: The two-compartment sink in our apartment has two drains. When washing in one of the sinks the detergent bubbles up and foams up from the drain in the other side. We tried different detergents, and using both hot and cold water, but the results are the same from either side. Can you suggest a solution?

A: One of two things could be the cause: Either the common drain into which the two sinks empty is partially clogged somewhere along the line or the inside of the tap; or the vent pipe that goes up through the roof is partially clogged. Clearing either one or both should solve your problem.

Q: The floor over our crawl space has insulation under it, with the vapor barrier on top (under the floor). We have placed heavy polyethylene sheets over the ground and have added vents in addition to the ones left by the builder. But we still have a moisture problem. Condensation forms on the underside of the insulation and drips down onto the plastic.Can you tell us what is causing this and why the vents should be left open during the winter - doesn't this add to the fuel bill?

A: There are two things I can think of that could be causing your moisture problem. First, even though you have added vents, there may still not be enough cross ventilation. Vents should provide total vree openings of 1 square foot for every 300 square feet of ground area inside the crawl space, and they should be located where there is an ample cross-flow of air.

Second, although you say the floor is covered with heavy plastic, it could be that the sheets do not overlap enough where pieces meet (there should be at least 12 inches), or it could be you left some gaps where the ground is still exposed, especially around the edges.

As for leaving the vents open in the winter, if the insulation is adequate, the vents will not allow much heat to be lost; if closed they could lead to serious condensation problems that would and could cause structural damage as well.