Hot Roofs With Spray Foam

To the Editor:

I would like to compliment David Frane on preparing an excellent article on spray foam insulation (8/03). He covered the subject thoroughly and provided the industry with a good service in doing so. There are some additional issues that should always be considered when using foam insulation.

First, while applying foam directly to the underside of the roof decking to create unvented cathedral ceilings and conditioned attic spaces is an excellent idea, I would caution anyone considering it to use only an open-cell foam in that application. As open-cell foams are porous, any roof leak will become apparent immediately, allowing an opportunity to repair it before significant damage occurs. If closed-cell foam is used in that application, there is a strong possibility that any roof leak could go undetected indefinitely, allowing the structure to deteriorate and mold to form, with no indication of the problems until the damage is far along.

Second, in these insulated roof applications, you must carefully size your hvac equipment. Designs of this sort are so efficient, especially if the air handler and ducts are in the conditioned attic, that it is very easy to oversize equipment. If the existing equipment is remaining in a retrofit installation, it is very likely that the system will be so oversized that it will not adequately dehumidify the space. In either case, it is important to have an hvac contractor or engineer who is familiar with this type of construction assist in sizing new or altering existing equipment to provide for the correct conditioning of the space.

Keep up the good work.

Carl Seville

SawHorse, Inc.

Atlanta, Ga.

Refrain From Disparaging Others

To the Editor:

In the article "Spray Foam Insulation," the author states, "Unfortunately, because both fiberglass and cellulose installations are typically subbed out to the lowest bidder, vapor retarders, air barriers, and the insulation itself are often thrown into place with little regard to quality." This statement unfairly insinuates that insulation contractors of materials other than foam are poor installers. It is the individual contractor who either performs poorly or installs a premium product. Nowhere in the article does the author refer to shoddy spray-foam installers, who are also prevalent in the insulation industry. If the author wanted to write an article about a quality product, he should have refrained from disparaging others in the insulation business. "When quality is a more important consideration than price," the builder or homeowner does have alternative choices in quality insulation products besides spray foam.

Stephanie O'Hanlon

WarmTech Solutions

Yarmouth, Maine

Shingle Warranties Warning

To the Editor:

I have two comments regarding the article "Spray-Foam Insulation." First, most asphalt shingle manufacturers want ventilation directly under the sheathing, because they do not want heat buildup to shorten the life of the shingles. Putting insulation directly against the sheathing will void the warranty for many asphalt shingles, if not all.

Second, should there be a leak in the roofing material, you not only wouldn't know where it was coming from, but you could ruin much of the sheathing around the leak before you would be aware of the leak.

Jerry Eby

Borkholder Buildings & Supply

Nappanee, Ind.

Foam Density Clarification

To the Editor:

I have just read the article on spray foam insulation. Thank you for a long overdue, well-written article. Unfortunately, there is an inaccuracy. When comparing 1/2-pound foam to 1.8-pound foam, the author indicates that the 1.8-pound product is more expensive because it contains more chemical. This is misleading. The denser products do have slightly more chemical, but they also carry double the R-value per inch. When basing cost of products by R-Value, the cost is nearly identical.

Blair Johnson

National Sales Manager

Corbond Corporation

Bozeman, Mont.

Code Conflict in Sealed Crawlspaces

To the Editor:

It was with great interest that I read that Parker and Orleans Homebuilders is committed to sealed crawlspaces (In the News, 8/03). As an individual in Mr. Tooley's profession, I totally agree that open crawlspaces cause moisture problems. I also agree that the construction details are important. The one detail in the article that is very important, but not pointed out, is the viewing strip problem. This detail cripples the insulation properties of the crawlspace area. In fact, studies at Oak Ridge have indicated that the viewing strip almost renders the crawlspace uninsulated. Until we as building scientists and code officials solve this situation, solving the moisture problem by requiring viewing strips creates a comfort problem and increases utility costs for the consumer.

Tom Coburn

Home Energy Savers

Glen Allen, Va.

Safety Lessons Effective

To the Editor:

"Safety Lessons" (8/03) was a great article. It is useful to have food for the imagination as motivation to use personal protection equipment and safe practice. I've not taken off my safety glasses while at work since reading that article. The photo of the worker in the belt harness, however, shows him in violation of OSHA standards for fall restraints. Belt harnesses are no longer acceptable (and I wonder that they ever were). Can you imagine falling to the end of your tether in one of those? A full body harness with a shock-absorbing lanyard attached to a D ring in front or back combined with a retractable fall arrestor is best.

Timothy L. Johnson

Tim Johnson Construction

Alton, Ill.

Thanks for your letter. There's a distinction between harnesses and body belts: Harnesses are required if there's a possibility of a fall, but body belts are okay for "positioning" a worker to prevent a fall. That is, you can't use a body belt where there's enough slack to let you fall over the edge of a roof, but you can use one (as in the manufacturer-supplied photo we used) if its purpose is to prevent you from getting close enough to the edge to fall off. Look at the photo and I think you'll see that it's effectively tethering the worker away from the edge. Even if he tried to fall off, he wouldn't be able to without undoing the belt. --The editors