QIs it possible to put plywood sheets on our attic floor to create storage space? Our attic has loose, blown-in insulation -- can we put plywood on top of that? -- G. Richardson

AThe type of construction used in the attic can present more of an obstacle than the insulation. If your attic has rafter-and-joist construction, providing space that is generally open, you should be able to add storage platforms without much trouble.

However, if the attic has truss construction, which was used in many houses during the last few decades, you would have a problem. Trusses have V-shaped braces running across their length, which block much of the space, and they usually cannot be altered without weakening the roof and floor of the attic.

In general, before making any changes in your attic, no matter what the construction, you should check with the building-code office in your municipality. A building permit might be required in some areas, and a building inspector might want to take a look to make sure the attic will support the extra weight of storage.

Insulation is usually not a big problem unless it is very thick and its depth is well above the tops of the floor joists. It is important not to compress insulation, and a little air space should be left on top of it for ventilation. If your insulation does extend above the joist tops, the joist depth can be increased by screwing strips of wood to the tops of the joists in areas where you want storage platforms. For example, if the insulation is one inch deeper than the joist, screw lengths of 2-by-2s (actually 1-1/2 inches thick) to the tops of the joists in the storage area. Then screw plywood at least 5/8-inch thick to the tops of the strips. It is best not to use nails -- the pounding can damage the ceiling under the attic.

We installed storm windows over our 35-year-old single-pane windows a couple of years ago to cut heating and cooling costs. In cool weather, the second-floor storm windows get condensation on the inside of the glass. We keep our house warm because of young children -- could that be a cause of the condensation? Should I add caulk to the inside of the windows? -- J. Wright

First, check the bottoms of the problem windows to make sure the little "weep holes" have not been blocked by caulk. These are small slots that must be kept open to let moisture escape. If the weep holes are open, the condensation is probably caused by loose interior windows.

Here is what is probably happening: Warm, moist air from the first floor rises to the second floor and some of it escapes through small gaps in the interior windows. The surface of the outside storm windows is colder than the inside windows, and when the moist air contacts these cold surfaces the water vapor condenses, causing fogging and dripping between the windows.

The remedy is to seal the interior windows to keep moist air from escaping. You can do this with weather-stripping and caulking compounds available at home centers and hardware stores. Good possibilities are DAP's Seal 'n' Peel, a caulk that can be removed when the weather changes and you want to open windows (www.dap.com), or removable plastic inside storm windows (www.frostking.com).

You might also have to reduce the humidity in your home by venting bathrooms, kitchen and laundry room to the outside with vent fans. If you are using a humidifier, turn it off or set it back.

Our toilet whistles when we flush it. How can we stop this? -- A. Sheffield

If a toilet makes whistling or groaning noises after flushing, it is often a sign of wear in the fill valve. This valve, located in the left side of the toilet tank, often has a float ball and rod attached to it.

To check whether this is the cause, close the water-supply valve under the toilet. This line sends water to the tank after a flush. Do this while the whistling is in progress. If the whistling stops, you have found the cause.

Fill valves are not too difficult to replace. Parts are available at most home centers and hardware stores.

Questions and comments should be sent to Gene Austin, 1730 Blue Bell Pike, Blue Bell, Pa. 19422. Send e-mail to doit861@aol.com. Questions cannot be answered personally.