Insulating a Cathedral Ceiling


Dear NH,
I want to insulate the space between my den's cathedral ceiling and the roof. Can I just blow insulation in from the roof peak by removing the shingles and boring holes in the plywood? I read about this method in a magazine article. The article said this was once frowned on but seems to be the choice now. One local builder told me this once, but other roofers I talked to didn't believe me. Now I am really confused. Can you help?
NN

Dear NN,
Blowing insulation between the roof and the drywall in a cathedral or vaulted ceiling is the easiest way to insulate this space. This can be done as you describe, but it must be done carefully so that there are no voids... areas without insulation.

Unfortunately, this installation can be potentially damaging to the roof unless there is some sort of ventilation under the roof deck. This is accomplished in renovations or new construction by installing special molded foam spacers that keep an air gap between the roof and the insulation. This allows a path for cooling air to move freely from a soffit vent to the ridge vent. Of course, many older homes did not have this sort of ventilation system built in, so if one wanted to insulate the ceiling, there was no realistic ventilation option except tearing down the finished ceiling... or ignoring the problem completely!

The two potential problems are 1) overheating of the roof deck, leading to premature aging of the shingles and 2) moisture from your home rising into the insulation, condensing and causing rot or mildew in the framing (along with lessening the efficiency of the blown insulation).

The results in your home are, in gambling jargon, a "crap shoot"! In any given home neither or both consequences may occur, depending on all sorts of factors, such as the total amount of air infiltration into the home (which would lessen moisture problems), the number of shade trees (which would lower roof deck temperatures) and the region of the country you live in.

The experience of roofers who know your area and have seen the problems should be helpful in determining the best way to do this sort of insulation retrofit, as well as consultation with insulation installers who use a variety of insulation products. Be wary of articles on any home repair situation that give you "the answer", especially when there are regional or local concerns. Realistically, all we writers can do is give you a variety of options... many possible "the answers". Only an experienced local professional can give you a more definitive local solution for your problem.
NH

COPYRIGHT G.G. ALONZY


Have a small home repair question for THE NATURAL HANDYMAN? Just click here www.naturalhandyman.com/aitikia
For more home repair information, visit NH's growing list of original home repair articles and quality links www.naturalhandyman.com
If this information has been valuable to you, please consider making a small donation to support NH's free service to the home repair community! For more information, please visit our "Friends" page www.naturalhandyman.com/friends
The Natural Handyman Site Directory

Stay Connected with TDS





Subscribe to TDS Newsletters

Join over 250,000 other subscribers!

Join Fido!

Discounted movie tickets
Sign up for Savvy Savings at TDS and get a free membership for discounted movie tickets!

Your Email:


The Dollar Stretcher
Dollar Stretcher Parents
Dollar Stretcher Tips
Financial Independence
The Computer Lady
Computer Lady Lessons
Healthy Foods

Your Email:


View the TDS Privacy Policy.