Q We will be installing mock beams (1-by-8 inch by 10-foot-long fir) on the cathedral ceiling of our mountain cabin. Couldn't we just stain and oil the beams before nailing them up, then fill the nail holes once the beams are in place? Georgiana Hall Orlando, Fla. Pre-staining and finishing applied trim members is quite common and will save you a lot of extra effort. Be careful when nailing the beams not to dimple the wood with the hammer. Finished wood is hard to sand and fill.
It is best to sink the last one-eighth-inch projection of the nailhead with a nail set or punch. Many paint stores have putty in stick form, already colored, to match their stains. You can also use Wood Dough or any wood-pulp putty to fill the nail holes as it accepts the stain well. Q I wish to cover my wood-shingle roof with a fire-retardent material without having to reinforce the structure because of the increased weight. Any ideas? Dr. Kenneth S. Sharpe Orange, Calif.
A wood-shingle roof can easily be covered with an underlayment sheet and then new asphalt-fiberglass shingles. With a rustic pattern, the roof has a very pleasant texture because the shingles conform slightly to the shingles underneath.
A metal shingle is approximately twice the cost and has a different look. The Architectural Engineering Products Company, 3650 California Street, San Diego, Calif. 92101, and Alcoa Building Products, PO Box 716, Sidney, Ohio 45365, produce quality products. Q Our 15-year-old home is surrounded by oak trees which keep our cedar-shake roof constantly shaded and damp. As a result, we have moss and fungus on the roof. Can you suggest a way of getting rid of the moss and fungus and a treatment for the shingles to prevent future growth? Lou Nelson St. Paul, Minn.
The Red Cedar Shingle and Handsplit Shake Bureau of Bellevue, Wash., suggests that you first wash the roof with a high-pressure hose, squirting from the top down. Let the roof dry and then treat it with any ``penta'' family of fungicides and preservatives. Products such as Woodlife, Pentaseal, and Woodtox contain a 5 percent solution. Nontoxic products for the same purpose include Cuprinol and CWF. All of these products can be bought from any local paint store. Q I would like to know which is the more practical and economical method of redoing the exterior of my home. It is now covered with white asphalt and I am considering either painting the asphalt or installing a new siding. What would you do? Helen J. Grano Bloomfield, N.J.
Not knowing just what type of asphalt siding you have now, it is difficult to recommend painting. If the siding is like asphalt floor tiles, the chances are it is quite oxidized on the surface and will require a good wire-brushing and washing down before priming and painting. On the other hand, if it is of the mineral-surfaced, black-asphalt, impregnated-felt-matt variety, then it will not accept paint because the asphalt will bleed through.
Re-siding with one of the many available products can give the house a fresh, new look, but it will be many times more expensive than paint. I'd ask for a price from one of your area's most established, reputable painting contractors even before I began looking at a new siding. Q For 16 years the paint on our ceilings has peeled. It began soon after an insurance contractor repainted some fire-damaged areas with what we feel was a poor-grade paint. We live in a damp area and some friends have told us that the cause could be mildew under the paint. What do you think? Lorraine A. Parmelee Ross, Calif.
This sounds like improper preparation of the surface by the insurance painting contractor. The fire probably put a heavy layer of soot, grease, and resins on the ceiling. The painting contractor didn't thoroughly wash off the residue before repainting.
Mildew would show up with discoloration of the paint. Also, dampness would have to have a source, such as a roof leak or an attic with poor air circulation.
I suggest a heavy sanding of the ceiling down past the damaged paint layer. Seal the surface with a clear, penetrating sealer and then repaint. It's a lot of work, but it should solve the problem once and for all.
If you have a question about designing, improving, or maintaining your home, send it to the real estate editor, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. Richard A. Kent is a practicing architect and general contractor in southern California.