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-   -   insulation questions (http://www.diychatroom.com/f103/insulation-questions-156014/)

pattiann4 09-06-2012 09:19 AM

insulation questions
 
older home--75-100 yrs old. Looking to insulate attic. Attic is not used for living space.
Presently has "balsam wool" insulation between the roof rafters & it's disintegrating. Floor of attic has no insulation at all. Attic is fully floored with T & G boards. My question is: how important is a vapor barrier? Contractor wants to pull up some flooring and blow in cellulose. Ok, but there won't be any vapor barrier. Since I don't use the attic space, is it feasible to just roll out some insulation over the existing flooring? And, if so, should I use faced insulation ? The ceiling below is plaster & I would suspect has been painted a number of times over the course of 75+ yrs. Would a number of paint coatings (some probably lead-based) act as a vapor barrier ?

joecaption 09-06-2012 09:27 AM

You need to first go back and edit your profile so everyone will know where you live so they can advise on how to proceed.
Differant areas have differant needs.

How is the attic vented?

pattiann4 09-06-2012 10:22 AM

vents
 
full length ridge vent & 2 gable vents

joecaption 09-06-2012 10:31 AM

If there's a ridge vent then the gable vents need to be covered up on the inside.
If not all the ridge is doing is sucking air in from the gables not the soffit vents like it needs to.

Are there any soffit vents, and are they not blocked with insulation so they can do there job?

Without those vents it's like trying to suck on a straw with your finger over the tip.
http://www.soundhome.com/article/roof-venting-systems

pattiann4 09-13-2012 07:48 AM

insulation questions
 
there are no soffit vents, but I can see little bits of daylight in a number of places. There was insulation stuffed into these areas (which I have removed).
I have installed the foam "rafter vents" to allow the air to rise to the ridge. I have removed the old balsam wool insulation from the rafters (what a mess).
My plan is to put R-30 vapor barrier insulation on the floor of the attic, as attic is not used. I have closed the gable vents. Since the old balsam wool had a r factor of about 3, I really expect a great improvement with the R-30.

oodssoo 09-13-2012 12:17 PM

Any type of modern blown in insulation would better IMO. It will take less time and effort to just blow in the insulation. Also, another thing to consider, blown in insulation can get into spaces that batt insulation can't. So consider this option to be less time consuming and will likely work better.

Gary in WA 09-13-2012 11:49 PM

I agree. Blow-in is the best bet here, after removing all the floor-boards(if truly an attic with undersized floor joists for future living area) except an access path down the middle. Cellulose doesn't require a vapor barrier; http://www.cellulose.org/HomeOwners/...orBarriers.php

Imperative to air-seal the attic first; http://www.homeenergy.org/show/artic...page/2/id/1386

http://www.google.com/url?sa=t&sourc...wWATQw&cad=rja

Ceiling sag; http://www.energyguide.com/library/E...SubjectID=8375

You do need air movement over the cellulose to move any moisture from below, outdoors- supplied by soffit intake venting, preferably continuous screened.

Gary


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