Weather is main factor in drying wood

Q. What length of time do you recommend for drying between power-washing and primer application?

A. It depends entirely on the weather. The safest way to find out is with a moisture meter. You should be able to rent or borrow one from an obliging painting contractor, but feeling with your hand is often a good-enough guide. If you are planning to use latex, dampness is not a problem, but if you are planning on using an oil-based primer or paint, the wood must be dry.

Q. Last month, we had our asphalt driveway dug out and replaced in conjunction with our neighbor's driveway. After the old driveway was dug out and gravel was laid, they replaced some cement sidewalks for us, and then poured the new asphalt. Shortly after the asphalt was laid, we noticed a white substance that seemed to have seeped up through the top of the asphalt. When we called the asphalt paving company, they came out to look at it and said they had no idea what had caused this defect. His only suggestion was that perhaps we spilled something on the driveway, and we told him emphatically that neither we nor our neighbors had spilled anything. It continued to get worse and seems to have now stabilized.

We had some people out who suggested there was too much limestone in the gravel that had been placed as a base, or perhaps the cement trucks cleaned their chutes out in our driveway and the excess cement ended up in the gravel and worked its way through the surface. The company has not made any suggestions for resolution of this defective driveway and seems to be ignoring us. Would you have any suggestions for resolution? We've attached some pictures for you to see as well.

A. The photos show an interesting pattern of the stains. It appears as if something was spilled or dumped at the head of your driveway and is flowing down toward the house. Looking at the photos, I doubt that it is anything coming through the asphalt - it would not look like that. It looks as if something was dumped on the driveway from a wheelbarrow that may have had some cement slurry in it. Or some slurry ran out of the concrete truck chute. Was any work done on the city sidewalk at the head of your driveway?

At this point, it does not really matter what caused the stains; you want them removed. Get some muriatic-acid mix from a building supply or hardware store, or buy muriatic acid and mix it one-part acid to 10-parts clean water and apply it to a small area of the driveway. Scrub the area with a stiff fiber brush with a long handle and see if it removes the white stain. If the whitish stains are cement, it is very likely that it will work. If it does, scrub the entirety of the stained areas. If it does not, try pressure-washing with a detergent.

Be very careful handling muriatic acid, it's a very potent chemical - wear heavy rubber gloves and other skin protection, including eye protection. Do not pour water into a container with the acid already in it; always pour the acid gently into water. If all else fails, wait until the driveway is 2 years old and apply an asphalt-base rubberized emulsion seal coat on it (avoid cutback asphalt, a very shiny sealing compound).

Q. What is the best caulk I can use to seal around my shower door. Where can I buy it?

A. Try DAP Kwik Seal PLUS Premium Kitchen & Bath Adhesive Caulk w/Microban. You may wish to check the DAP Web site www.dap.com and click on Products, Caulks and Sealants, Kitchen/Bath. You will see several choices. The advantage of the caulks with Microban is they contain a mildew-resistant ingredient.

Q. Just wanted to drop you a short note concerning your response to a question on metal roofing. First, how does wind affect oil-canning? As I understand, oil-canning is caused by the expansion and contraction of the metal due to the change in temperature of the metal as it is exposed to the sun. Also, what does the wind have to do with sound on the roof? I believe, if the concerned party goes with 24-gauge material, both concerns will be reduced, if not eliminated. The heavier gauge material should reduce oil-canning and reduce potential "telegraphing" of the materials beneath. As for noise, I think this is a common misconception among the uninformed. If the metal roof is placed on a solid roof deck, noise should not be an issue. I am most interested in your response to the oil-canning caused by wind phenomenon.

A. Wind can lift metal sections off the substrate by creating negative pressure on them. It can also get under the sections at the eaves. Both of these will cause oil-canning, which is similar to a sail flapping in the wind. Expansion of the metal under the influence of the sun is not oil-canning - a repeated "boing boing boing" sound as when one squeezes an oil can. To duplicate this sound, take a piece of sheet metal that's long enough and start shaking it. Sun-caused expansion of the metal causes one or more single sounds.

Regarding your comment that using 24-gauge metal should reduce or eliminate noise, please read my answer again and you'll see that I have said just that. Whether informed or uninformed, placing a metal roof directly over a solid deck will not prevent noise from either oil-canning or expansion from the sun's action. Telegraphing of the underlying shingles will occur in time regardless of the gauge of metal used.

Q. I have a 10-year-old larger home with three hot-air oil heaters. The way the oil prices are going up every day, I am very much concerned about the price for the upcoming winter season. One of my friends suggested a heat pump to add on to my current system. Can you please explain to me what a heat pump is? Can I really add to my current system and does it really make any economic sense?

A. A heat pump is a unit that extracts heat from the outside air in winter to warm a building and acts as an air-conditioning unit in summer. It is powered by electricity. The cost of the unit and its installation will be considerable, so you'll have to calculate if you will save enough to warrant the capital outlay or save anything depending on the cost of electricity in your area.

Q. Could you please advise as to how one might install reflective attic foil. Is the investment worthwhile? I have read different methods of installation on various sites and would want your input. Does it in fact reflect up to 92 percent of radiant heat?

A. The effectiveness of reflective foil used in attics depends on the climate in which you live. It is most effective at keeping attics cooler in hot climates as it works year around, whereas in milder and colder climates it only helps keeping the attic cooler in summer. If your purpose is to improve the energy efficiency of your home, the most effective way to do so in any climate is to add insulation on the attic's floor. Reflective foil is usually stapled to the bottom of the rafters. As for the percentage of radiant heat it reflects, not having the means of testing it, I would defer to the scientific community's findings.

Q. Please help me if you can. About four years ago, I had a concrete patio installed in my back yard. Recently, the concrete has been scaling off layer upon layer. The person who did this job is no longer in business and cannot be contacted. Can you tell me if there is anything I can do to remedy this concrete peeling and scaling? I cannot afford to replace the entire patio.

A. Concrete will spall (scaling) from a variety of reasons. If the spalling is extensive, you are better off having a competent mason or concrete contractor perform the repair. If the scaling is small enough that you to wish to handle it yourself, you can do so with Thorocrete. Be sure that you follow the directions carefully. You should be able to buy Thorocrete in well-stocked hardware and building-supply stores.

Q. Almost four years ago, I had a 16-by-30-foot deck built using GeoDeck synthetic decking. This past summer, I began to notice that some of the planks were becoming cracked, and subsequently learned that the material had been recalled. This, I learned, was because an ingredient to protect against UV damage was left out of the mix. Unfortunately, since my deck is in at least partial shade a good part of the time, it took a while for the deterioration to begin, and by the time I filed a claim, the company had run out of money and shut down the recall. I had to have 10 of the damaged 20-foot boards replaced at a cost of $850. My question: Is there anything I can apply that would protect against UV damage without discoloring the decking?

A. GeoDeck claims that it offers a limited 20-year warranty against splitting and other ailments. You should have been able to get them to honor it and give you new boards. If they have refused, it does not speak well of the company; others interested in GeoDeck, take note. There are stains that provide UV-ray protection, but they will change the color of the decking. A paint store can help you sort that one out.

Q. For the past year, I have noticed piles of sand on my cellar floor at the base of the walls, which are poured concrete. There seems to be an increasing amount of sand at these areas. The soil around my house is mostly sand. Do you know what might be causing these "sand piles," and should I be worried about them? Thanks for any advice that you can give to me.

A. You haven't said, but I assume that your cellar floor is also concrete. The sand piles you see may be brought into your cellar by hydrostatic pressure from below the floor. Have you had any signs of water penetration? Or the piles may be the work of small sand ants. If there are only a few piles and they are not very big, there is probably no need to be too concerned.

To prevent further piles from accumulating, check the grade around the house; flat or negative grade allows water to seep along the foundation walls that can build up pressure under the cellar floor. If the grade slopes away from the foundation, water is unlikely to reach the base of the foundation walls and creep under the floor. If you can determine that the piles are the work of small ants, pour boiling water at the center of the piles to get rid of the ants.

Q. I have a house with white aluminum siding on it and after some 30 years it is starting to fade. I am considering painting it. Should I use a primer and secondly what type of paint should I use? I would use an airless spray gun to do the job.

A. Pressure-wash the siding with a mixture of fresh Clorox bleach and detergent to remove all pollutants. Rinse thoroughly. Then paint with any paint formulated for metal (some come with a built-in primer) or two coats of a top-quality latex exterior paint.

• Henri de Marne's column appears Sundays. He was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.

© 2008, United Feature Syndicate Inc.