Extra insulation on Garage/interior wall?
 

I am thinking of adding insulation to our attached garage wall, to
increase the insulation between the living space. Is adding Dow
styrofoam board or something similar a good idea, or worth the cost?
(It's more flammable than the 5/8 fireshield)

For example, the Dow 1" stryofoam board would add R5 to my wall, which
is only 3.5" with R-11 fiberglass.

Thanks guys!

Extra insulation on Garage/interior wall?
 

"Scott Mathers" wrote in message
...
I am thinking of adding insulation to our attached garage wall, to increase
the insulation between the living space. Is adding Dow styrofoam board or
something similar a good idea, or worth the cost?
(It's more flammable than the 5/8 fireshield)

For example, the Dow 1" stryofoam board would add R5 to my wall, which is
only 3.5" with R-11 fiberglass.

Thanks guys!

If when you stand in the house near that wall, you feel colder than another
exterior wall or if the wall feels cold to the touch, it may be worth it.
One cannot give an objective answer to the question as posed. Going from
R-11 to R16 seems like a small step but if the wall is cold, it may make the
difference you want.

If you are just looking for ways to randomly cut your energy budget, you
want to more carefully consider the costs. At best you will see less than
10% savings over total. Making up optimistic numbers: Lets say your
heating bill is $200 per month in the winter (5 months) and you save 5% by
installing the insulation that comes to $10 per month or $50 per year. How
much is that insulation going to cost you?

If you are trying to improve the comfort in a certain part of your house, it
will be worth the cost even if the payback is long.

Extra insulation on Garage/interior wall?
 

"Scott Mathers" wrote in message
...
I am thinking of adding insulation to our attached garage wall, to
increase the insulation between the living space. Is adding Dow
styrofoam board or something similar a good idea, or worth the cost?
(It's more flammable than the 5/8 fireshield)

For example, the Dow 1" stryofoam board would add R5 to my wall, which
is only 3.5" with R-11 fiberglass.

Thanks guys!

Exposed foam is a fire fuel looking for an ignition source. Please provide
the source for this foam board. with 1" equals R-5... I bet you did not read
the whole listing. This rating is part of an assembly.

More insulation in the attic seems a better bet. I added R-30 this summer
and cut the a/c bills in half from July to August and more than 40% since.

Extra insulation on Garage/interior wall?
 

"SQLit" wrote in message
...

Exposed foam is a fire fuel looking for an ignition source. Please
provide
the source for this foam board. with 1" equals R-5... I bet you did not
read
the whole listing. This rating is part of an assembly.

Nope extruded board is 4.92
http://www.glacierbay.com/dowtest.asp
http://www.dow.com/styrofoam/na/pro-...s/perimate.htm

It is a fire retarded material, but should be covered with drywall to meet
fire codes.

The OP may want to look at this too
http://www.dow.com/styrofoam/na/pro-...erior_wall.htm



More insulation in the attic seems a better bet. I added R-30 this summer
and cut the a/c bills in half from July to August and more than 40% since.

Why not both?

Extra insulation on Garage/interior wall?
 

"SQLit" wrote in message
...
:
: "Scott Mathers" wrote in
message
: ...
: I am thinking of adding insulation to our attached garage
wall, to
: increase the insulation between the living space. Is adding
Dow
: styrofoam board or something similar a good idea, or worth
the cost?
: (It's more flammable than the 5/8 fireshield)
:
: For example, the Dow 1" stryofoam board would add R5 to my
wall, which
: is only 3.5" with R-11 fiberglass.
:
: Thanks guys!
:
: Exposed foam is a fire fuel looking for an ignition source.
Please provide
: the source for this foam board. with 1" equals R-5... I bet you
did not read
: the whole listing. This rating is part of an assembly.
:
: More insulation in the attic seems a better bet. I added R-30
this summer
: and cut the a/c bills in half from July to August and more than
40% since.
:
:
No, he's apparently looking at the "blueboard" type stuff, or
pink, whichever. Codes here do say it needs to be covered
though, which makes sense anyway; being exposed leaves most
anything susceptible to damage. In fact, that's stamped right on
the blueboard - I just looked at a leftover piece on the porch.

While I'm thinking of it; the OP should also beware the
possibility of the foam boards, creating a second vapor barrier -
shouldn't let that happen - easy to remedy if the wall's are
going to be opened at all.

Extra insulation on Garage/interior wall?
 

Pop wrote:
"SQLit" wrote in message
...
:
: "Scott Mathers" wrote in
message
: ...
: I am thinking of adding insulation to our attached garage
wall, to
: increase the insulation between the living space. Is adding
Dow
: styrofoam board or something similar a good idea, or worth
the cost?
: (It's more flammable than the 5/8 fireshield)
:
: For example, the Dow 1" stryofoam board would add R5 to my
wall, which
: is only 3.5" with R-11 fiberglass.
:
: Thanks guys!
:
: Exposed foam is a fire fuel looking for an ignition source.
Please provide
: the source for this foam board. with 1" equals R-5... I bet you
did not read
: the whole listing. This rating is part of an assembly.
:
: More insulation in the attic seems a better bet. I added R-30
this summer
: and cut the a/c bills in half from July to August and more than
40% since.
:
:
No, he's apparently looking at the "blueboard" type stuff, or
pink, whichever. Codes here do say it needs to be covered
though, which makes sense anyway; being exposed leaves most
anything susceptible to damage. In fact, that's stamped right on
the blueboard - I just looked at a leftover piece on the porch.

While I'm thinking of it; the OP should also beware the
possibility of the foam boards, creating a second vapor barrier -
shouldn't let that happen - easy to remedy if the wall's are
going to be opened at all.


Hmm, good point on the vapor barrier... What would I do?

I was thinking of blue board, then 5/8" fireshield on top of it.
I just finished insulating my attic! It was woefully under-insulated, I
live in NY and only had 3.5" in most of the house.

Thanks for all of the replies guys!

Extra insulation on Garage/interior wall?
 

"Scott Mathers" wrote in
message ...
: Pop wrote:
: "SQLit" wrote in message
: ...
: :
: : "Scott Mathers" wrote in
: message
: : ...
: : I am thinking of adding insulation to our attached garage
: wall, to
: : increase the insulation between the living space. Is
adding
: Dow
: : styrofoam board or something similar a good idea, or
worth
: the cost?
: : (It's more flammable than the 5/8 fireshield)
: :
: : For example, the Dow 1" stryofoam board would add R5 to
my
: wall, which
: : is only 3.5" with R-11 fiberglass.
: :
: : Thanks guys!
: :
: : Exposed foam is a fire fuel looking for an ignition source.
: Please provide
: : the source for this foam board. with 1" equals R-5... I bet
you
: did not read
: : the whole listing. This rating is part of an assembly.
: :
: : More insulation in the attic seems a better bet. I added
R-30
: this summer
: : and cut the a/c bills in half from July to August and more
than
: 40% since.
: :
: :
: No, he's apparently looking at the "blueboard" type stuff, or
: pink, whichever. Codes here do say it needs to be covered
: though, which makes sense anyway; being exposed leaves most
: anything susceptible to damage. In fact, that's stamped
right on
: the blueboard - I just looked at a leftover piece on the
porch.
:
: While I'm thinking of it; the OP should also beware the
: possibility of the foam boards, creating a second vapor
barrier -
: shouldn't let that happen - easy to remedy if the wall's are
: going to be opened at all.
:
:
: Hmm, good point on the vapor barrier... What would I do?
:
: I was thinking of blue board, then 5/8" fireshield on top of
it.
: I just finished insulating my attic! It was woefully
under-insulated, I
: live in NY and only had 3.5" in most of the house.
:
: Thanks for all of the replies guys!

Basically, just damage the previous vapor barrier. Slash it up,
whatever, so air/moisture can get thru it. Kind of depends on
the situation.

Pop

Extra insulation on Garage/interior wall?
 

Pop wrote:
"Scott Mathers" wrote in
message ...
: Pop wrote:
: "SQLit" wrote in message
: ...
: :
: : "Scott Mathers" wrote in
: message
: : ...
: : I am thinking of adding insulation to our attached garage
: wall, to
: : increase the insulation between the living space. Is
adding
: Dow
: : styrofoam board or something similar a good idea, or
worth
: the cost?
: : (It's more flammable than the 5/8 fireshield)
: :
: : For example, the Dow 1" stryofoam board would add R5 to
my
: wall, which
: : is only 3.5" with R-11 fiberglass.
: :
: : Thanks guys!
: :
: : Exposed foam is a fire fuel looking for an ignition source.
: Please provide
: : the source for this foam board. with 1" equals R-5... I bet
you
: did not read
: : the whole listing. This rating is part of an assembly.
: :
: : More insulation in the attic seems a better bet. I added
R-30
: this summer
: : and cut the a/c bills in half from July to August and more
than
: 40% since.
: :
: :
: No, he's apparently looking at the "blueboard" type stuff, or
: pink, whichever. Codes here do say it needs to be covered
: though, which makes sense anyway; being exposed leaves most
: anything susceptible to damage. In fact, that's stamped
right on
: the blueboard - I just looked at a leftover piece on the
porch.
:
: While I'm thinking of it; the OP should also beware the
: possibility of the foam boards, creating a second vapor
barrier -
: shouldn't let that happen - easy to remedy if the wall's are
: going to be opened at all.
:
:
: Hmm, good point on the vapor barrier... What would I do?
:
: I was thinking of blue board, then 5/8" fireshield on top of
it.
: I just finished insulating my attic! It was woefully
under-insulated, I
: live in NY and only had 3.5" in most of the house.
:
: Thanks for all of the replies guys!

Basically, just damage the previous vapor barrier. Slash it up,
whatever, so air/moisture can get thru it. Kind of depends on
the situation.

Pop


Doh. What will be difficult, is that the vapor barrier would be on the
wrong side - the blueboard would be on garage side (non-living space
side). Will that be a real problem?

Extra insulation on Garage/interior wall?
 

Owens Corning Super Tuff-R is my insulation board of choice. It is R 6.5 per
inch with a foil shield on each side. Although it is the highest R value of the
commonly available sheets, it is also the cheapest. I just covered my new 2
story addition with it. It is very easy to work with and cuts a lot easier than
the Foamular products.

Owens Corning has a very nice FAQ on their web site covering most questions
about their products. Tuff-R is approved for use on the inside or outside of a
wall. It does not pose any problems from a moisture barrier standpoint.

Since I had different walls in different stages of construction right now
(northern Ohio), it is interesting to see how the condensation differs.

On walls where I have only R13 fiberglass with stapled kraft paper barrier,
there is some moisture collecting underneath the insulation (on the inside of
the outer osb wall).

On the walls that also have 1/2" Tuff-R on the outside, there is no
condensation, since the osb is far warmer.

Dennis

Extra insulation on Garage/interior wall?
 

....
:
: Basically, just damage the previous vapor barrier. Slash it
up,
: whatever, so air/moisture can get thru it. Kind of depends
on
: the situation.
:
: Pop
:
:
: Doh. What will be difficult, is that the vapor barrier would
be on the
: wrong side - the blueboard would be on garage side (non-living
space
: side). Will that be a real problem?

Unfortunately, I'm the wrong one to be able to give a reliable
answer to that one. My guess is, yes, it could be a real problem
because two vapor barriers will collect moisture between them
which cannot escape. As a result, mold and wood rot might get a
good start, plus freezing/thawing effects depending on a lot of
things.

I think DT in the next post has a pretty reasonable alternative
if you can afford it. I do know you have to avoid multiple vapor
barriers but in your case I have no assistance I can offer. It
would definitely be better to go to something that's not a vapor
barrier in and of itself.

Pop

Extra insulation on Garage/interior wall?
 

I live in central NY and I think you should bring your attic up to an
R38. This can be done by either fiberglass or cellulose blown in
insulation.

Is your garage wall colder than other exterior walls? It shouldn't be
any worse than other exterior walls if you keep your garage door
closed. You may think this is a silly statement but I've heard a few
insulators grumble because they get calls from disgruntled homeowners
but when they check on the situation they find that many of them leave
their garage doors open for extended periods of time.

If you install Dow Styrofoam or Dow Tuff R both must be covered by 5/8
type x drywall for two reasons. 1) Both products have high flame
spread/smoke developed characteristics and must be covered by code. 2)
Your garage wall is probably a one hour fire rated wall and will lose
that rating if it doesn't have firecode drywall on both sides of the
wall.

Extra insulation on Garage/interior wall?
 

jgb wrote:

If you install Dow Styrofoam or Dow Tuff R both must be covered by 5/8
type x drywall for two reasons.

Section §RR318.1.2 of the NY State Residential Code requires 1/2"
gypsum board over all foam. There's no mention of anything thicker or
that it must be Type X.

1) Both products have high flame
spread/smoke developed characteristics and must be covered by code. 2)
Your garage wall is probably a one hour fire rated wall and will lose
that rating if it doesn't have firecode drywall on both sides of the
wall.

Section §302.3.3 exception 2 of the Building Code of NY State requires
5/8" Firecode for the garage ceiling if there are habitable rooms over
the garage, if not, then 1/2" drywall is acceptable for the walls and
ceiling.

R

Extra insulation on Garage/interior wall?
 

I was under the impression that the wall(s) between the house and the
garage had to be a one hour fire-rated wall. Perhaps this isn't true.

Extra insulation on Garage/interior wall?
 

jgb wrote:
I was under the impression that the wall(s) between the house and the
garage had to be a one hour fire-rated wall. Perhaps this isn't true.

In MA I believe the house-to-garage door must be rated at 2 hours.