Q--Our 26-year-old home needs a new roof. The architect who designed the house advised us to consider a roof that is first covered with tar, then a layer of stones. The roof, which has a very low pitch, is shingled now. What do you suggest?
A--I find it odd that your architect would recommend what is known as a tar and gravel roof for your home. The reason is that tar and gravel roofs are usually used only in situations where the roof is totally flat or only very slightly pitched. Because your roof is shingled, I assume it must have at least a 15 degree pitch (or roughly ``3 and 12.`` This means the roof rises 3 inches for every 12 inches of building width. Since this is commonly considered the lowest pitch for a successful shingle job, I believe what you consider ``a very low pitch`` must be at least this height. Tar and gravel roofs are generally used when the pitch is below 3 and 12.
The only explanation I can think of for this recommendation is that perhaps you`ve experienced leakage, and he or she thinks the tar and gravel is better protection from this. In any case, I suggest you replace your old shingles with the new mildew-resistant fiber glass shingles available today. Glass-fiber-based shingles are usually more durable than their organic-based cousins. The inorganic mat won`t absorb water. As a result, the shingles tend to resist curling, buckling and blistering. The built-in mildew resistance will prevent this fungus from forming unsightly streaks on your roof. As a bonus, glass-fiber-based shingles tend to have longer warranty periods than organic-based shingles.
Use an ice and water shield under the shingles. This is a membrane that protects against ice and water build-up, as its name implies, and resultant leakage. It must be applied directly to the plywood, so you`ll have to remove the old shingles first. Extend the membrane from the eaves line to 2 feet within the outside wall. (The line where the inside wall meets the roof line is usually a weak spot, because there`s a lot of heat loss here.) Beyond that, the attic space is generally cold enough to prevent melting ice and the subsequent back-up.
Q--I would like to refurbish my old storm windows. What is the safest way to remove old putty wihout breaking the glass?
A--The only storms I`ve seen that are glazed with putty have wooden frames; I assume that`s what we`re talking about here. Most putty gets extremely hard over time. We`ve found the best way to remove this aged material is with a heat gun and a standard 1-inch stiff putty knife. Designed to remove paint, a heat gun looks like a hair dryer but generates more intense heat. This heat softens the putty, allowing easy removal with the stiff knife. You must be careful not to heat the glass too much, or it can crack. I`ve found this is usually more of a problem with divided light windows with lots of little panes than with the standard one- or two-pane storm. If the wooden frames are relatively dry, treat them with raw linseed oil; let it soak in overnight. Reputty with a good-quality glazing compound. Rolling the putty in your hands until it`s soft and pliable will make it easier to work with, giving the best results. Use the same 1-inch stiff putty knife to reapply it. Q--My bathroom and bedroom ceilings are peeling badly. Can I use an electric sander on them, or do I have to smooth them out by hand? Can I repaint with textured paint?
A--Use an electric orbital sander to remove the loose, flaking paint from these ceiling surfaces. Then spot prime the bare areas. If there have been several coats of paint on ceilings over the years, the surface will probably be quite irregular. Textured paint is a good choice here, because it will build up the bare spots, bridging any gaps for a smooth, even surface.
Q--I`ve seen a prefabricated house that uses polystyrene-foam walls as insulation. Are you familiar with this kind of home? If so, what is your opinion of the polystyrene-foam walls?
A--I have seen some structures like this. The brand I`m most familiar with has 8-inch-thick polystyrene-foam walls sandwiched between plywood. It`s a superefficent home that`s relatively low in cost. Usually, you can put whatever kind of siding you prefer on the outside. Natural wood on the inside walls is quite common, but you can use plasterboard or dry wall, too. The homes usually have high-quality, energy-efficient windows, making them a good energy bargain. What I`ve heard about this kind of structure generally supports this; the heating costs are usually relatively low. The brands I`m familiar with have considerably low square-foot costs (in the Northeast) in terms of energy efficiency.
Do you have a question about your old house? Bob Vila, host of the PBS show ``This Old House,`` funded by Owens-Corning, will answer questions of general interest about rehabbing and renovating. Send your questions in care of Know-how, 435 N. Michigan Ave., Chicago, Ill. 60611. Sorry, letters cannot be answered personally.