INSULATING AN A-FRAME

As a Handyman I often receive questions about insulation, here is one example:

The Client wrote:

I have an A-frame three-story home. The third floor is used as living space, leaving only the area between the plaster ceiling and the roof for insulation. I was considering blowing in cellulose insulation to fill these six inches of space, but I have some concerns:

v Would six inches of cellulose insulation make much difference?
v Would this cause the roof not to breathe and lead to roof damage (the insulation would block the surface vents along the roof)

What can I do?

My reply:

According to The U.S. Department of Energy, up to forty-five percent of our home's energy losses are through the roof. With this in mind, any insulation you can add will help.

To answer your first question, cellulose insulation is a great choice, especially since you have very limited space. Cellulose has a high R-factor per inch in comparison with other types of insulation. If you can get six inches of cellulose insulation installed, that would give you around an R-22 value. The suggested R-value for attic spaces in the U.S. range from R-19, in the warmer parts of the country, to R-49 in the colder parts. Normally, I would recommend that you check with your local Building Department to find out what R-factor is recommended in your area. Since you only have six inches of space with which to work, you are not going to do better than minimums anyway. R-22 is worth it in any part of the country.

As you know, venting the attic space is very important no matter how small the space. A well-vented attic space makes for a healthier house, but since you only have a six-inch space with which to work, it makes it difficult to insulate and ventilate this space. Your situation is truly a hard one to rectify, but there are special venting systems made for these difficult-to-ventilate spaces. If you were going to fill this space with cellulose, I would recommend using a specialty vent called an Air Chute. This vent is installed in each rafter space, and needs to be vented at the bottom either in a soffit or an attic space.

Depending on your style of roof, it makes a difference how you vent the topside; normally this is done with a ridge vent. These “AIR CHUTE” vents are made of different materials. I prefer the plastic ones, when installing them in a retrofit situation. The cardboard ones are great in new construction because you can staple them up between the rafters as you go, but in your case you will not be able to attach them. The plastic ones will allow you to shove them in between the rafters and the insulation will hold them up against the bottom of the roof.

CALL YOUR HANDYMAN AND TAKE A KID FISHING