View Single Post
  #3   Report Post  
Posted to alt.home.repair
Paul M. Eldridge Paul M. Eldridge is offline
external usenet poster
 
Posts: 415
Default Insulation 1 1/2 story

On Fri, 14 Mar 2008 10:21:09 -0500, Tazz
wrote:

I have a 1 1/2 story home. The upstairs bedrooms get pretty warm in
the summer.
I recently bought double paned vinyl windows, This helped SOMEWHAT
last year.
Since it is a 1 1/2 story I do have access to all the outside walls
other than the window walls.
There is old insualtion in between the studs that are exposed. I have
access to all that. Easy to work on.
The insulation has PAPER on the one side that faces into the attic.
This insulation is old and worn. What I want to do it to get some
insulation boards 4'x8' x 3/4" with the foil on one side. Really like
to cocoon both rooms.
Questions

1. If I am installing the insulation board do I still need insulation
in between the studs on the wall?
2. If I need the insulation in between the studs on the wall does it
need to be with OUT the paper if I install the insulation board over
it...?
3. If I install the insulation board over the existing insulation
thats in the wall can there be moisture build up in between the new
insulation board and the inusaltion with paper on the outside of it.?

Everything I have seen says to encapsulate the uptairs. Even plug off
the pathway on the kneewalls that are from the front of the house to
the back inbetween the floors. No insualtion in between the floors but
plug iff so no air can travel in between the floor.

Any help would be greatly appreciated.

Marty


Hi Marty,

With respect to question #1, it would seem foolish not to insulate the
wall cavity prior to installing the insulation board. I take it the
foam board you have in mind is rated at R6 or R7? If that's the case,
3.5 inches of fiberglass will provide you with another R12 or R13,
effectively tripling the thermal performance of this wall, at a very
nominal cost.

#2: I'll defer to others on this one, but my sense is that you should
forego a paper facing if you plan to install a foil backed product on
top.

#3: Again, as with #2 I'm not the best qualified to answer this, but
you could slice or remove the paper backing if this is a concern. Is
the R-value marked on this insulation? If it's old, it may be only R7
which means it should be replaced with R12 or R13. I'd also caulk and
seal all cracks and joints while the wall cavity is accessible.

Cheers,
Paul