QThe drywall ceilings in my townhouse are riddled with popped nails. I want to repair the damage and repaint the ceiling. How can I fix this and make sure the nails won't pop again? -- Martha

AYou can repair the existing popped or protruding nails, but there is no guarantee that more nails won't pop in the future. Drywall nails pop because of shrinkage in the wood framework where they are attached. Many drywall contractors use screws instead of nails to attach the drywall, which helps eliminate popping.

When you make your repairs, use -inch-long drywall screws, which can be bought at any hardware store. These slender screws have coarse threads and thin heads. You should use a power drill-screwdriver to drive them.

Drive a screw about 1-1/2 inches from each popped nail, making sure the screws go into the ceiling joists and hold the drywall firmly. Each screw should be driven so the head sinks just slightly below the surface of the drywall, but without tearing or breaking the drywall's paper cover. If the screws are difficult to drive, drill pilot holes slightly smaller than the screws to make entry easier.

When the screws are in place, remove the protruding nails by grasping the heads with locking pliers and twisting them out. Finally, use drywall joint compound to fill the nail holes and smooth over the heads of the screws. When the compound is dry, sand the patches smooth, then prime and paint the ceiling.

We have a wood deck, supported by posts, and want to replace it with a sun room that will last many years. The contractor wants to build the sun room on the existing deck posts, which are pressure-treated wood. He said he would have an architect look at the posts. What do you think? -- M. Thompson

If you want the sun room to last many years, it will need a proper foundation. I have no way of knowing if the existing deck posts will serve, but I would certainly be wary. You should make sure the building inspector for your municipality sees the plans for the sun room and issues a permit for its construction. If possible, have the building inspector check the posts. Building requirements vary in different areas, but building additions of this type often require a masonry foundation.

Our attic is well ventilated and we have been using it for storage. This year we have had severe growth of mold on our asphalt-shingled roof. I removed the mold with roof cleaner but it was very hard work and time-consuming. Could I use a power washer? What could be causing the increase in roof mold? -- J. Attick

When using any cleaning product, you should follow the manufacturer's instructions. A roof cleaner should be applied with a garden-type sprayer, allowed to work, then rinsed off with a forceful spray from a hose-end nozzle. Power washing (pressure washing) at high pressures would damage the shingles. If used at all, a power washer should be set to deliver no more than 500 pounds per square inch, and a skilled operator is recommended.

You can help prevent future growth of mold by installing zinc strips on the roof. Rain water washing over the zinc causes a chemical reaction that inhibits mold growth.

I blame recent wet, humid conditions for an increase in roof mold in some areas.

I have tried everything I know of (bleach, cola, Tang and so forth) to remove a yellow stain from the waterline in my toilet. Nothing has worked. Can you help? -- Nan

Some of the concoctions you are using could be making the stain worse. Bleach usually does the job if given a chance to work.

Try pouring about a cup of chlorine bleach into the toilet water. Scrub the stained area with a toilet brush and let the solution stand for a couple of hours, then scrub again and flush.

If that doesn't work, try this: Sprinkle some non-abrasive cleaner onto a wet toilet brush and scrub the stained area thoroughly. Many supermarkets also sell special toilet-bowl cleaners that should eliminate your stain.

I've heard of many home-made remedies for toilet stains. White vinegar sometimes works, and a few denture-cleaning tablets dropped into the bowl can help keep it sparkling. Flushing after every use will help keep stains from forming.

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.