Basements, Attics and Crawl Spaces - advice on attic insulation?

looking for advice...i have a storey and a half older home..looking at blowing in insulation in attic...my floor is tongue and grooved in attic....so instaed of tearing up floor iwas looking at blowing 1 foot of insulation over floor and down into the roof eaves( have just installed vents for these)

by doing this.. there will be a space of about six inches under the floor not insulated....will this be a problem or is this ok?

Thanx in advance onad

Have you considered drilling the T&G and blowing insulation under that floor. The space can create problems if the temp in that cavity gets low enough to condense moisture out of warm air that leaks in. If you consider a cross section of any insulated space where it is very cold outside and warm inside, the temperature will vary from one temp to the other as you look at different points between the two surfaces. Somewhere in there the temp will drop below the dew point and that is where the moisture can start to be deposited. Not saying it will, just that it has the potential. That same condition can and does occur in the back of cold closets.

If you use a hole saw and save the plugs, you could support and glue them back in place and then bury everything. Or just bury the holes.

Bud

thanx for the response... it just wasn't sitting well with me ..that space under the floor... didn't even think about possible moisture problem.... if i did go with drilling holes.. wouldn't i have to worry about any fixtures ( light fixtures) under the floor....

i guess what i'm trying to say...is it better just to tear up the floor and box the fixtures then blow in over everything?

onad

If you have recess lights, they are an issue all in themselves. What you want is air sealed and IC (insulation contact) rated. Without those two designations, then adding insulation is a problem and air/moisture is a problem. Boxing around them is always a first thought, except it is not recommended. You would then be containing the heat and air flow that the units need to vent to stay cool. If it one or two it is easy to change them out. Twenty, like some homes I know and it becomes a little more difficult. I believe I have read that there is a way to modify the units to use a pin type CFL. That way someone doesn't come along a year from now and install a regular bulb.

If removing the floor is an option, I would consider it to give you better access to install the insulation to a uniform depth without a wood floor in between. Also, while you have access to the ceiling below, air sealing is perhaps the number one improvement for energy efficiency and there would be no better time. Electrical, plumbing, and chimneys. A cellolose insulation will contribute to the air sealing as well. Fiberglass will not.

Bud

thanx Bud for the help ...i really appreciate the advice

onad