Q I have long admired white-painted brick homes. Now that I own a brick home I would like to paint it white. How often would I have to repaint it? If I lacked the time and money to repaint, would the brick weather to a soft pink as others have? Should I use special primer and paint? Is there an insulating paint? Mrs. Barbara H. Seaman Harrisburg, Pa.
Clay masonry walls after proper original priming and painting might need refinishing every three to 10 years.
The quality of the materials, condition of the brick, and the application workmanship determine the longevity of the paint.
If the repainting is neglected, we really do not know if the masonry would weather to a pink color. You might ask the occupants of a brick house so rosied for an answer.
First, painting of red brick can be successful if done properly, but it can be a disaster if shortcuts are allowed. First, the bricks must be totally dry. After a good rain they may take weeks to dry out. Most paint stores rent a gauge to determine dampness.
Second, when the brick is oven-dry, prime the wall with what is called a surface conditioner, which can be found at many paint stores. One company, Frazee Paints & Wallcoverings, PO Box 2471, San Diego, Calif. 92112, makes such a primer with an epoxy additive called Evakote, but there are many others. Surface conditioners may take three to five days to dry.
Third, apply one or two coats of a top-grade pure acrylic flat latex emulsion.
We know of no paint with a significant insulation characteristic.
Foremost in expertise in clay-masonry matters is the Brick Institute of America, 1750 Old Meadow Road, McLean, Va. 22102. You can reach the institute at (703) 893-4010. It publishes a pamphlet called ''Technical Notes on Brick Construction, Painting Brick Masonry, 6 Rev. May 1972,'' which covers the brick-painting field in depth.
Note: We emphasize that the present condition and the original and anticipated quality of materials and workmanship basically determine the longevity of the paint.
Q My mobile home metal roof needs to be reroofed or patched. I would prefer another type of roofing. How about urethane? Lorraine W. Stroup Malibu, Calif.
The least expensive method is to patch the mobile home metal roof. Leaks are probably at the seams, which can be readily ''gooped.'' The more permanent method with added insulation as a dividend is a professionally applied urethane roofing.
Urethane is finally waterproofed with a coat or two of latex paint. Every few years repaint the surface for added longevity.
Q My 55-year-old cast-iron furnace finally let go and I've been told that rugged cast-iron burners are no longer made. Would you know of a company that makes a furnace that can stand on its own feet and carries a good guarantee? Henry B. Dunseith Mattapoisett, Mass.
Durable cast-iron boilers are indeed being made these days. Two manufacturers are Weil-McLain, Michigan City, Ind., and H. B. Smith Company, Westfield, Mass., but there are many others.
The Weil-McLain guarantee for at least one 1977 boiler in the residence of M.C. Treadway Jr., Bristol, Conn., carried a one-year guarantee on boiler parts, plus an additional 19-year warranty on the cast-iron core section.
If you have any questions on gas rates and conditions in your local area, contact the servicing utility company. No Pest Strips To the real estate editor:
(This letter is in response to an earlier letter to the Ask a Builder column which suggested the use of No Pest Strip to rid a house of silverfish.)
Caution readers that a No Pest Strip, if placed in close proximity, will ''cure'' an aquarium of tropical fish, regardless of what the container says.
I found this out, much to my chagrin, three days after placement near my tank. Paul W. Marsh Urbana, Ill.
If you have a question on designing, improving, or maintain your home, send it to the real estate editor, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115. Forrest M. Holly is a longtime California builder now living in southern Arizona.