Home repair: Carpeting has little insulation impact

Q. We have hardwood floors under our carpeting and are considering either replacing the carpet or removing it and having the floors refinished. There have been several different carpets laid over the floors in the past 50 years, so we’re not sure of the condition of the floors. Is a home warmer when wall-to-wall carpeting is used?

A. The rage today is hardwood floors. So you can see what condition the floors are in after removing the carpet and then decide if refinishing them is needed and worth the cost. Carpeting will provide a modicum of insulation to a first floor over an unheated basement or crawl space, but it will feel much warmer if you walk on it barefoot because fewer of your feet’s nerve endings are in contact with the carpet than would be if the floors were denser like wood or tile. Carpeting would have no insulating effect on a second floor.

Q. I have a two-car garage attached to my house. The garage is aboveground, and the outside is siding. The two-by-fours are all exposed, and I want to insulate and drywall them. Do I use paper-faced fiberglass insulation or unfaced and cover it with plastic before drywalling? Is there a better way? The ceiling is drywalled and insulated with a drop-down ladder for access for storage.

A. If you are thinking of heating your garage, keep in mind that this will increase the corrosion from road salt brought in by your cars. Considering the amount of moisture cars bring into a garage in the winter, it is best to use unfaced insulation and plastic. Paint the drywall with B-I-N and two coats of quality latex paint.

Q: Concerning the article about not using calcium chloride on concrete, does that include asphalt driveways?

A. Your question alludes to my warning that the latest research from the National Ready-Mix Concrete Association says that contrary to earlier recommendations, calcium chloride causes damage to concrete. However, this does not apply to asphalt.

Q. I read your article about crawl space insulation. We also have a crawl space, and I did much of what your article included — a bit differently. I insulated the floor joists with fiberglass, but I put the Kraft face out, away from the living space, facing toward the crawl space floor. Then I put Poly up, covering the insulation and floor joists. Is this a problem having the Kraft face down and then covering it with Poly? The dirt floor is covered with Poly, and the crawl space is open to the main cellar with a 3-square-foot opening. I’m going to put rigid insulation on the crawl space walls. I run a dehumidifier during the warm weather.

How does all of that strike you? Should I make any changes?

A. What you have done is trap within the joist cavities any potential moisture migrating from the living space, where it will not be able to dissipate safely into the crawl space. If you have a plywood subfloor, the risk is lessened because plywood is an effective vapor retarder, but it is still risky.

It would have been preferable to install the insulation with the Kraft paper against the subfloor, holding it in place with tiger’s teeth (buy them in building-supply houses), and to omit the plastic under the joists. Unless you prefer to remove the plastic and turn the insulation over, I suggest you keep an eye on the situation and open up a few places yearly to see if you notice any moisture problems developing.

Rigid insulation on the crawl space walls will help condition the space, but be careful not to risk cracking your foundation walls by insulating lower than three feet below grade — unless you know you have an effective foundation drain, the backfill is made of coarse material to within a foot or so of the grade, and that the grade and all appendages are sloping away from the house with no mulched flower beds against the foundation. If you do not have gutters, there should be some masonry units on the ground at the drip line of the roof to prevent the small ditch that would result from rain falling on uncovered earth.

The masonry units can be concrete patio blocks, flagstones or whatever else you choose that will not absorb water (bricks will not do). If the masonry units are set flush with the sloping grade, they will deflect the rain from the roof away from the foundation. It is best to plant grass against a foundation and keep flower beds and shrubs a few feet away. A side benefit is that you can enjoy them from inside.

Q. I spend all of July and August at camp and would like to turn off the power to my pump and furnace in my home during that time. The furnace man said it wasn’t a good idea, but I worry about leaving things on. The furnace is oil, the heat is hot water, and the furnace heats the domestic hot water. The pump is in the cellar, not a submersible. Do you have an opinion? Thank you for your helpful columns.

A. You can turn the thermostat controlling the boiler way down; heat will not come on and, because the house will be empty, there will not be any call for hot water. For safety’s sake, I wouldn’t recommend shutting the power off for your sump pump, just in case there is need for it to operate.

Q. The caulking around my bathtub is quite old and dirty. I am having difficulty removing it. Should I continue to remove all of it before putting on new caulking, or can I put the new caulking over the old? Do you have a recommendation for the best type of caulking for this project?

I also want to remove stickers that my children put on their sliding doors in their bedrooms roughly 15 years ago. The stickers are hard to remove with just water and rubbing. Is there a product to make this task easier without discoloring the wood or leaving marks on the door?

A. You should remove the old caulking. Because it is old and dry, it is probably an oil-based or latex-type product. Try 3M Caulk Remover.

My favorite tub caulk is Sikaflex-1a, a polyurethane caulking/sealant/adhesive, but it needs a week to air-cure properly (there are other polyurethane caulks available). If you can’t keep it dry for a week, it will turn a dirty yellow/pink. If you cannot wait a week, try DAP Kwik Seal Plus Premium Kitchen & Bath Adhesive Caulk w/Microban. For that reason, I tried DAP some time ago and commented that it seemed to work well. It remained sparkling white and did not mildew. Unfortunately, I discovered that it began to peel off the wall in about a year, whereas Sikaflex-1a remained as solidly attached to the wall as it was when I put it on years ago. The DAP is still very white, while the Sikaflex-1a is slightly gray.

So your choices are Sikaflex-1a with minor discoloration and tough adhesion or DAP’s color retention and loss of adhesion, which means that it will need to be replaced.

To remove the stickers on the wood doors and trim, heat them with a hair dryer to soften the adhesive and peel them off. Then remove the adhesive remnants with cooking oil.

Q. I have been following your articles on venting bathroom fans for years. In 2001, I had my roof re-shingled and thought it would be a great opportunity to move the vents for my two second-story bathrooms from the roof to the gable sidewall as you had suggested. My only problem with the roof-vent installation was that the heat from the vent would cause icicles to form directly under the vents on the roof edge. There is no ice-dam problem on any part of my roof.

Owing to an installation error by the roofers when they were moved to the gable wall, I had water leaking from the vent pipe as a result of the bell end of the pipe facing away from the fan. I rectified the problem by sealing the joint. I did not reverse the pipe, as it would have been a difficult job. There is a slope to the vent pipe so that condensation runs out the vent, not back toward the fan.

I have had additional insulation blown on top of the original insulation in the attic space, so the pipe is well buried. My problem is that during the winter with below-freezing temperatures, the vent flap freezes in place as a result of the condensation running out of the pipe.

During the winter, I am unable to use the bathroom exhaust fans when the temperature is below freezing. I bought what I thought was a good vent. I believe it is spring-loaded and works fine in above-freezing conditions. It closes securely with an additional flap at the fan end. The enclosed photo was taken when the temperature was 37 degrees, so there is no ice buildup on the flap. You can see a little ice below each vent. Is this a common problem with spring-loaded vents in cold climates? Or was there an installation error?

A. Your problem is why I recommend that venting is best done through a south- or west-facing gable wall — the sun helps melt the ice forming at the jacks. Doesn’t the flap at the fan housing keep cold air from getting into the bathroom? You should check to see if the fan is properly installed; the flap should be hinged at the top. It would be surprising if you didn’t have other problems apart from the formation of ice dams at the eaves from the roof fan venting. Where did the condensation go? It usually wets the insulation and stains the ceiling, and it also can rust the fan and its housing. If the fan is installed in a wall, the condensation can drip to the floor and eventually cause rot.

Did you notice any large ants in that area? Those are the main problems with roof venting.

Q. In an earlier answer to a reader about radiator placement, you also suggested insulating solid-masonry homes. Can you provide information about this procedure?

A. Solid masonry walls are built with an outside brick face and inside wythe made of four-inch blocks or terra-cotta tiles in older homes. Plaster is usually applied directly to the block walls or drywall to furring strips. The best way to insulate such walls is to apply rigid insulation to the interior finish and drywall over it. All existing trim should be removed and replaced after the drywall is finished, unless the house has beautiful oak trim, often found in older houses, which should not be done away with. In such cases, a matching wood piece that is deep enough to come flush with the added insulation and drywall should be installed next to the trim. Insulating from inside is not perfect, as any intersecting partitions will be in the way, but they should represent only a small heat loss.

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 e-mail at henridemarne@gmavt.net.

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