There are several ways to insulate a crawl space

 
Posted4/15/2018 6:00 AM
hello

Q. We have a basement under most of the main level of our 1960s split-level home but only a cement crawl space under the room I'm using as my office -- and it's not insulated and cold! The entrance to the crawl is about 4 feet off the basement floor. We have a "door" made of a rigid insulation panel keeping warm air in the basement (and from the crawl space) and keeping a crawl space smell out of the basement. I'd like to add insulation to the ceiling of the crawl space. The room above has wood floors. Can I use rigid insulation or would fiberglass batting be better? The vents to that room also run through the crawl space -- should I also somehow insulate the vents?

A. There are two different approaches to this question.

Since the crawl space has a concrete floor, and you haven't mentioned any leakage problem, except for a musty smell, consider insulating the exterior walls of the crawl space with 2-inch thick XPS applied to clean foundation walls with dabs of polyurethane caulking.

Remove the insulated panel between the basement and the crawl space.

The crawl space will now become conditioned by warm air from the basement and the radiation from the heat ducts within it. This will solve the problem of insulating the ducts and may eliminate the crawl space smell.

The other way is to install Roxul mineral batts (no itch and healthier than fiberglass) between the first-floor joists, making sure that the batts are in contact with the floor sheathing. In that case, you should insulate the ducts, using special insulation for that very purpose.

Q. I am hoping you can help me with a warranty question. I had a house built in 2009 and have had trouble with shingles coming off during strong wind storms several times over the years since the very beginning. The builder has been great about sending a roofer up each time to patch the areas. Last year I had enough of sleepless nights and barking dogs from the noise of shingles flying off and flapping at all hours of the night.

I told the builder that something is wrong and he finally admitted that they had put on a bad batch of shingles and were having the same trouble with a house built at the same time as mine in another town. I mentioned that shingles have warranties and can't he get them replaced. He said that he will work with the shingle company on the warranty, but in our discussion he mentioned the labor cost for replacing them would not be covered under said warranty.

I know that it is not the builder's fault that they put bad shingles on my house, but it isn't my fault either and I should have had good shingles put on in the first place. What is a fair solution to the cost of the roof replacement? He has me in his schedule for this summer to do the job. No mention has been made of any cost on my side and I didn't ask. I just want some good advice for when he does mention any cost for this job that he may feel is my responsibility. Who should pay for the labor?

One more question. I want the old shingles removed, not covered over with the new shingles. I know that you can put two layers of shingles on a roof. Is this an unreasonable request?

I do want to mention that this is a very reputable builder who does high-quality construction, and they have been great with anything that has had to be addressed so far over the years.

A. Your builder is correct: shingle warranties are usually prorated, based on the value of the remaining life of the shingles. Some manufacturers have more comprehensive warranties, but, if available, they should be paid for at the time of purchase.

Unfortunately, the tear off, disposal and labor to replace are usually the responsibility of the homeowner.

But there is another possible cause for the failure of your shingles (and that of those in the other house the builder mentions) that should be investigated. If the shingles were installed in cold weather and the seal tabs didn't have the chance to seal under the influence of the sun, the entire cost of replacement is the installer's responsibility. However, it is curious that the seal tabs didn't seal during the summers following the initial installation.

It may be difficult to ascertain the exact cause of the failure. It may be worth checking with the building-supply company; it may have additional data, such as reports of other failures during 2009.

It is difficult to advise you on who pays for what without determining the exact cause of the failure. If it is due to a bad batch of shingles, you would be responsible for all costs beyond the warranty's reimbursement. If it's because of cold weather installation, it's the builder's responsibility, but with the caveat mentioned above.

If it cannot be determined, the best you may be able to do is to split the cost of the total replacement.

I agree with you that the failing shingles should be removed and the new ones applied onto a properly protected roof sheathing. It is not an unreasonable request.

Q. Our 1960s vintage house has baseboard convectors on a hot water system. They collect a lot of dust in the closely spaced fins. I finally thought of the proper tool to clean between them: Foot-long colored pipe cleaners from a novelty store. Long enough to stick behind the convector, flexible, and fluffy to catch the dust. Cheap and reusable, too.

But, the reason I was cleaning that convector was to take it apart and repaint it. In this system, there is a backing piece of sheet metal that is flush against the wall. When I removed the screws and took it out, I discovered that there was no drywall behind it, just an open space with some scraps of insulation. It's an exterior wall, of course.

I've seen the same thing in one other place in the house. My immediate reaction was to put in some insulation and a vapor barrier and screw on a piece of drywall.

Was that the right thing to do? Is there some reason to leave a wall open behind a convector?

A. There should have been drywall behind the convectors, just as on the wall above them. If the sheet metal is bright and shiny, it was probably installed to protect the framing from heat, as is done behind wood stoves. It also acts as a reflector to increase the heat radiation into the room. Any aberration in the insulation should be corrected, as you did. A vapor retarder may not be needed if the drywall repair is properly taped to the existing and the metal reflector is put back.

• 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.

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