To vent or not to vent a crawl space

Q. Should we ventilate our cabin crawl space or not? Our cabin measures 24-by-40 feet, has a 22-by-8-foot enclosed porch and seems to have been built sideways along a slight rise of fill adjacent to, or partially over, a ledge.

The crawl space has a dirt floor with clearance varying from about 3 to 4½ feet; the upside foundation is mostly below ground level while the opposite foundation is at ground level. The camp is centrally sited on about one-half acre with lake and marsh along two sides.

About 10 years ago we replaced floor joists and a central beam, which seem to have rotted out (since construction 30 years ago); they run the length of both the camp and porch. At the same time our contractor installed a continuous, construction-grade, plastic mat over the dirt floor. He also mounted an exhaust fan in one of the two openable windows located on opposite walls in the space. When we have lived in the cabin, we've ventilated the space with both window and floor fans, and the crawl space and air seemed dry.

Is powered ventilation of the crawl space necessary? Is passive or powered ventilation necessary when the cabin is occupied during late spring, summer and early fall? Even when the cabin is unoccupied?

I've encountered conflicting opinions about ventilating crawl spaces, usually without explanations, so I'm equally interested in learning reasons why ventilation is or is not important. Thank you.

A. The rot you experienced was likely a result of the previously bare dirt floor. The environment near a lake and a marsh provided ample moisture to contribute to the rotting problem.

Since your contractor laid a heavy plastic over the dirt floor, there should be no need to ventilate the crawl space.

In fact, research conducted many years ago, in the 1970s by the National Association of Home Builders (NAHB) Research Foundation, shared with me by my good friend, the senior analyst, resulted in the recommendation that a dirt floor crawl space thoroughly covered with plastic does not need ventilation and that ventilation actually encourages problems.

The reason ventilation was found to cause serious problems, especially in the Southeast, is that it brings in a considerable amount of moisture during the warm and hot weather. The framing absorbs this moisture and no ventilation is able to dry the framing to a point below which deterioration occurs.

Consider leaving the windows closed year around, but check the crawl space when you move in and when you move out: The best test is the "nose knows best." If the crawl space smells OK, you have nothing to worry about.

When I built our house in the late '70s, following the research mentioned above, we didn't install any vents in the crawl space and covered the bare soil with two layers of 6 mil plastic. I checked the crawl space regularly and it always smelled sweet.

Q. As our painted drywalled garage walls are peeling, our neighbor said the previous owners painted the drywall but did not prime them first. How can we solve the peeling problem? Can we repaint the inside garage walls with latex after sanding the peeling areas?

A. A garage is subject to moisture and considerable temperature fluctuation. If the previous owners didn't use green board, they should have.

The drywall should have been primed and painted with two coats of a quality exterior latex paint.

You can sand the peeling areas, prime the walls with Zinsser Bulls Eye 1-2-3 Gray Primer and paint them as mentioned above, but there is the strong possibility that peeling will continue and be aggravated by the additional weight of the new coats.

Q. I'm very happy to see you are still publishing your column. Very many people benefit from your knowledge, including me a few years ago. I now have a new problem: hard water stains on my shower glass walls. The well water seems to have almost etched the glass. Do you know of any way to fix this?

A. Try the most ecological way first. Spray lemon juice onto the glass, let it stand for 20 to 30 minutes and rinse off with a squeegee. Or cut a lemon in half and rub the stains with it, let it stand for 30 minutes and rinse and squeegee.

Or spray white vinegar and carry on as above. If this is not successful, spray white vinegar, let stand for 30 minutes and then gently rub the stains with baking soda applied with a soft, nonabrasive pad. Rinse thoroughly and squeegee. You can also add lemon juice to the vinegar to increase its potency.

There are many commercial cleaners, but they need ventilation and should be applied with rubber gloves. Follow the manufacturer's instructions carefully.

Some effective commercial cleaners are also toilet bowl cleaners, The Works, Kaboom, etc.

Q. Several months ago you referred to a furniture cleaner/polish that should be available in local hardware stores. But for the life of me I cannot recall the name of the product.

We have Conant Ball furniture (butcher block style) throughout our home and it does not have a polished finish. We were able to get a cleaner we have used for many years from a fellow who did re-upholstery work and actually made a couple of foot stools to coordinate with a couple of our chairs. Since then, however, he has moved out of our area and we are unable to get any more of this oil-based product from him.

I'm wondering (hoping …) if the product you wrote about is anything comparable to what we have used?

A. The furniture polish and cleaner I have frequently mentioned and which we are regularly using on all our teak furniture is Milsek Furniture Polish & Multi-Purpose Cleaner, the original Milsek product. They now have many products suitable for a number of purposes (www.milsek.com).

It was recommended to me by a Pennsylvania reader many years ago when the product was only available in the reader's area. Following her ecstatic endorsement, I bought a bottle by calling the manufacturer; it was truly miraculous, as she had said.

Now Milsek is widely available and is carried by Ace Hardware and others. Or you may want to click on Where to Buy on its website.

Not knowing what formula you have been using, I can't tell you for sure if Milsek will be compatible with your existing finish, but I don't see why it wouldn't.

Q. We just had a driveway installed (1,800 square feet) and we have a patio (600 square feet) of Unilock pavers. Come fall we plan on having them both sealed.

The pavers are multicolored and my wife likes the wet look. When it rains the pavers are shinny and we would like to have a sealant that will give us the high-gloss wet look. Are there any products you could recommend?

Our local Menards has Rustoleum Rocksolid wet look lacquer; it says it seals and protects concrete and masonry in low and high gloss ($29.88 per gallon).

A. Look into Alliance Gator's Hybrid Seal High Gloss + Color Enhancer (www.alliancegator.com.) Click on Products and click on Sealers in the drop-down menu, then click on the product mentioned above. To locate your nearest dealer, contact Alliance Gator at (866) 212-1611.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.