Home repair: To avoid staining, vent bath fans through gable walls

Q. We have a two-story Cape Cod-style house built in 1996 with two full baths upstairs. The ceiling vents are piped out to a louvered vent near the peak of the house, above the garage roof.

Several years ago, I noticed it was getting black around the vent. I have been cleaning the siding around the vent, but it is getting much worse as time goes by. I have since noticed a few other houses with the same problem, as well as some houses built around the same time as mine that don’t have any signs of the problem. What was done differently, and what can be done to stop it from happening anymore?

A. Bath fans should not be vented out through gable vents. Moisture discharged by the fans dampens the louvers and the siding around them, capturing dust in the air, because gable vents are intake vents. The dust causes the stains you have noticed.

Bath and kitchen vents should be vented as low as possible through gable WALLS, preferably on the leeward side, which is hopefully also the sunnier side of the house. It is best to use solid Schedule 20 bell-end drainpipe, sloping slightly from the fan to the outside, set just above the attic’s ceiling joists. The bell ends must be facing the fan and not the outside wall. Place 4-inch-thick fiberglass insulation snugly on each side and on top of the pipe to insulate it. Use an aluminum or plastic jack with a flap; avoid louvered jacks, as they have a propensity to break.

Q. I have been reading your column for many years and very much appreciate the information I have learned from it.

I am remodeling our main bathroom. We have a 48-inch vanity and a plate glass mirror that sets 5 inches above the countertop and is 48 inches long and 36 inches high. The mirror is 25 years old and in very good condition. Some of the silver on the back of the mirror has been affected by water getting under the bottom to the back of the mirror. The affected area is only around the sink area and is only about 1 foot long and one-half inch high at its highest point. Is there a do-it-yourself kit to restore this small area of the mirror without redoing the whole mirror?

A. There is no such kit, and even a professional glass shop cannot resilver the bottom of the mirror. However, a glass shop can cut an inch off the bottom of the mirror to eliminate the affected area.

Damage to the silver coating usually happens when the mirror sits directly on top of a backsplash. Water splashing onto the top of the backsplash works its way up the back of the mirror by capillary attraction. Mirrors should be set at least one-half inch above the top of the backsplash.

Q. I purchased an older bungalow a few years ago. The dining room ceiling was lowered for some reason, even though the roof is highly pitched. I would like to “open” the ceiling to its original height. I come from a handy family, thus I am considering a DIY. I believe this would involve spraying insulation (which I would hire done) and a drywall ceiling.

What concerns me, since it is an older bungalow, is whether asbestos would be a consideration. I’ve heard that if you leave asbestos alone, it will leave you alone. However, if I’m tearing down the low ceiling, how will I know if there is asbestos anywhere around? If I called someone on a consult, he would need to inspect before the demolition of the ceiling begins. Is a Zip-UP ceiling just for finishing basement ceilings?

A. Where do you think the asbestos may be? Is it in the lowered ceiling material? If the ceiling consists of 12-by-12-inch tiles that are stapled to furring strips or is a drop ceiling with panels that can be lifted, it is unlikely to contain asbestos. Residential tiles and panels are more likely to be made of cellulosic material, whereas commercial material is more likely to contain asbestos. However, it is wisest to have it checked. You can gently cut out one tile or remove one panel and take it to a laboratory that tests for asbestos. But if you are wisely concerned about the presence of asbestos in other areas besides the ceiling material, someone should come and inspect first.

Am I to understand that the ceiling in question is directly under the roof, and that if you remove it, you are exposing the rafters? Is that why you see the need for insulation and drywall?

A Zip-UP panel ceiling (an alternative to metal-grid drop ceilings) is not solely for basements, but without knowing more about what you intend to do and the actual conditions, I can’t tell you whether it will work for your installation.

Q. While trying to save on heating bills, I wonder if I am going too far. As you know, living in Vermont, the temperatures can get very cold, and I question whether lowering my thermostat to 60 degrees every night is too low. We have a new hot air furnace with a new thermostat that I programmed to lower at 9 p.m., as we go to bed around 11 every night.

A. Lowering your thermostat to 60 degrees is an effective way to save on fuel. If this setting is comfortable for you, stay with it.

Q. My next-door neighbor has St. Augustine grass that is taking over my velvet lawn. How do I get rid of this invasive grass and keep it from coming back?

A. St. Augustine grass is a warm-region grass found mostly in tropical and subtropical regions with abundant moisture. It spreads by means of surface runners and crowds out all other grasses and most weeds, which is why it is popular where it grows well. It is found mostly in the Southeast and in Texas, so I assume you are writing from that region.

Contact the Master Gardener division of the Extension Service of your state university for information on getting rid of the infestation in your lawn.

It is difficult to get rid of St. Augustine grass. But since it propagates by runners, can you install a plastic edging as a barrier at your property line, burying it several inches while leaving several inches above ground? I did that successfully many years ago to control the propagation of bamboo, which sends shoots just below the surface to start new plants.

Q. I know that you have addressed this in your column — sorry to bring it up again. What replacement window do you recommend for the Pittsburgh area? Our windows are now 33 years old and in need of replacement.

A. There are so many replacement windows on the market that it really boils down to what is available in your area and what fits your financial situation, as prices vary so much depending on whether you want all vinyl, all wood or a combination of wood inside and vinyl outside.

When buying all-vinyl windows, be careful to get top-quality ones; the many cheap models can get very leaky in cold weather as they shrink. One of the sales tactics of these cheaper brands is to demonstrate the difficulty of pulling a dollar bill through their meeting rails during a sales demonstration in your house.

Some vinyl replacement windows are very good and their cost is close to that of certain wood and wood/vinyl replacement windows. Check the websites of Kasson & Keller (www.ecoshieldwindows.com) and Gorell Windows and Doors (www.gorell.com). If these windows meet your requirements, contact the companies for the name of a local dealer or installer.

Wood and combination wood/vinyl windows are Marvin (www.marvin.com) and Andersen (www.andersenwindows.com). Either should be available everywhere.

Q. Thank you for your answer on my Insulbrick siding problem. Considering that condensation has been found to be a problem because this siding is made of asphalt and therefore is a vapor barrier on the wrong side of the wall, would it be wise to install a small exterior vent near the bottom of each bay to let the wall cavity breathe?

A. Installing small vents at the bottom of each bay would not be sufficient; you would need to do the same at the top. This would result in heat losses because air would circulate through the wall cavities, which I assume are also insulated. The decision is yours.

Q. Thanks for your reply (about choosing shingles). Wow — you’d think that good old market forces would have shaken out the bad shingle companies, and that the good ones would “rise to the top.”

Are there other roofing types (metal, slate) that I should consider for our 1890s typical rectangular-shaped, steep-roofed Vermont village house?

A. I regret that I was not able to recommend a shingle manufacturer to you, but I have received so many reports of problems and early failures from readers and contractors alike that I have decided to stay away from any recommendation.

Of course, there are a number of choices for other materials. The problem is the cost. Asphalt/fiberglass shingles are the most economical roof covering, unless you are considering screw-on metal panels, which any carpenter can install. Twenty-four gauge, double-lock standing seam metal roofing is a premium roof that should be installed by experienced roofing contractors. Avoid those trying to sell you a 26-gauge, single-lock standing seam roof at a more affordable cost, as it may come back to haunt you. The problems these cheaper roofs develop are “oil-canning” (clunking) in strong winds and leaking at the seams under certain snow and ice conditions.

Slates are also a premium roofing material and costly, and they require a stronger roof structure because of their weight. Even plastic slates are not inexpensive.

If you plan on living in the house for a long time, the more expensive options are well worth considering. They can also add to the value of your house at the time of resale because they do not have the relatively limited life expectancy of asphalt/fiberglass shingles, which in the last 20 or so years have had a history of premature failure, resulting in only about half of their claimed life.

Ÿ Henri de Marne 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 email at henridemarne@gmavt.net. His book, “About the House,” is available at www.upperaccess.com and in bookstores.

© 2011, United Feature Syndicate Inc.