Good R value for Attic in Northeast USA?
Michael Cunningham
I have been doing a lot of work in my attic lately
and noticed that my home only has R19 fiberglass insulation
in the attic. I was thinking about adding some more on
top using those sealed batts that come in a roll, but I am
not sure how much R value I should go for without wasting
money. I am located in the northeast USA so the temperature
can range from 0 deg to 100 deg F basically. Its a 2 story
colonial roughly 2200 sqft. What is a good r value for my attic?
Thanks for your help..
Mike
Eric Lee Green
http://www.buildingscience.com
Look at their recommendations for your area.
--
Eric Lee Green GnuPG public key at http://badtux.org/eric/eric.gpg
mailto:er...@badtux.org Web: http://www.badtux.org
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MrAoD
>Folks,
>
>I have been doing a lot of work in my attic lately
>and noticed that my home only has R19 fiberglass insulation
>in the attic.
R30, kraft-faced batts is recommended for attic flooring joists.
>I was thinking about adding some more on
>top using those sealed batts that come in a roll, but I am
>not sure how much R value I should go for without wasting
>money.
Assuming the current insulation has a vapor barrier, get another buncha R-19.
If there's a vapor barrier do *NOT* use kraft-faced, it'll trap condensation
and ruin the underlayer. The sealed rolls should be fine, just don't cover
soffit vents or exposed ceiling fixtures. Generally accepted principle is to
unroll the new batts perpendicular to the existing insulation (i.e., at right
angles to the joists).
Marc
Robert A. Barr
> In article <aab2eb52.03020...@posting.google.com>, Michael Cunningham ruminated:
>
> > I have been doing a lot of work in my attic lately
> > and noticed that my home only has R19 fiberglass insulation
> > in the attic. I was thinking about adding some more on
> > top using those sealed batts that come in a roll, but I am
> > not sure how much R value I should go for without wasting
> > money. I am located in the northeast USA so the temperature
> > can range from 0 deg to 100 deg F basically. Its a 2 story
> > colonial roughly 2200 sqft. What is a good r value for my attic?
>
http://www.owenscorning.com/foryourhome/features_list.asp
Michael Cunningham
Unfortunatly They dont seem to offer insulation (R value)
recommendations for my area. The talk about building materials
an such but no attic insulation recommendations.
Mike
Calvin Henry-Cotnam
>
> What is a good r value for my attic?
Your code will vary, but where I am located (Toronto area), our code
requires R31 in the ceiling, unless the house is electrically heated
in which case R40 is required.
For the roof/ceiling of a vaulted space, R20 is required (R22 for
electrical heating).
--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
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gogosroge
Go for another 20 of pink to get a total of R40! If you have those
wacky roof-truss-W-frame things, you might as well lay them in line
with the old ones, but at least off-set the ends. The most important
thing is to make sure the insulation doesn't touch the roof! The best
thing I've seen for this is foam thingies shaped like this:
__ __ __
\_____/ \_____/
With heating costs about to go through the roof (thanks to Dubya and
Colin) you better insulate!
PC
temperatures down to -20 F.
Phil
Maineyak
live in. (We are not stalkers) I mean Caribou, Maine and Paulsboro, NJ have
different requirements but both are considered the northeast.
OK I got that off my chest .. If you live in New England I'd recommend at
least an R-30 with a R-40 being preferred.
Now you can lay batts on top of the existing batts to achieve this. But the
preferred method is to blow cellulose on top of the batts to achieve the
desired R-value. This will cap the complete top of your living space and
will fill any voids you have in the existing batts. DO NOT BLOW FIBERGLASS
IN OPEN AREAS (as somebody suggested) Cellulose out performs fiberglass (in
open blow areas) and is cheaper and requires less inches to achieve the same
R-Value. Note: Blown fiberglass out performs cellulose in a closed cavity
installation because it doesn't settle like cellulose. You will need to wrap
any chimneys in this attic space with a fiberglass batt to the height of the
cellulose. Although cellulose is non-combustible they don't recommend
putting it next to chimneys.
Also forget the vapor barrier unless you want to pull up the old batts and
install 6 mil poly sheeting... waste of money if you ask me.
Hope this helps
Maineyak
"Michael Cunningham" <cra...@optonline.net> wrote in message
news:aab2eb52.03020...@posting.google.com...
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effi
news:3e49b1ce$1...@corp-goliath.newsgroups.com...
> First off.... Why don't people asking insulation advice give the state
they
> live in. (We are not stalkers) I mean Caribou, Maine and Paulsboro, NJ
have
> different requirements but both are considered the northeast.
> OK I got that off my chest .. If you live in New England I'd recommend at
> least an R-30 with a R-40 being preferred.
> Now you can lay batts on top of the existing batts to achieve this. But
the
> preferred method is to blow cellulose on top of the batts to achieve the
> desired R-value. This will cap the complete top of your living space and
> will fill any voids you have in the existing batts.
cap is a very descriptive term
as in seal the living space below from drafts, something fiberglass cannot
do
and contain the fiberglass, which is more problematic than cellulose
healthwise
cellulose may seal against outside noise better too