On Apr 17, 1:04*pm, "Bob F" wrote:
ransley wrote:
On Apr 16, 10:13 pm, wrote:
Hello all,

Looking for opinions on crawl space insulation. This is for an old
rent house on block and pad foundation. I am considering either R13
or 1 1/2" rigid foam (vapor barrier on one side and radiant barrier
on the other).

Fiber seems to have better cumulative R-value. However, I don't know
if bugs and crawlies nesting in it will be an issue. I can get the 1
1/2 for about 10 dollars a piece. Fiber will let me do this
incrementally as time allows.

Trying to get a feel on what is the better option.

thanks
richard

Foam board is easier to work with , not affected by moisture, no itch.

Getting foamboard to fit tightly will be way more work, IMHO.

Fiberglass looses R value as it gets colder near zero,

Really? Where did this come "data" come from?

filber glass

irritates but there are types they say dont but they cost more. Foam
should be easier to get an airtight seal between sheets.

Somehow, I doubt that. Cutting foam to fit, especially around cross bracing will
never be easy.

Fiberglas is considered poor for small currents that build up when
there is a high temperature differential. I guess the orientation is
also important. Cellular is better at blocking air flow, thus offering
better r value. Rigid foam has no
Air flow. I believe the thinner the glass fibers, the better r value.
I liked when corning made the no itch fine fibers.
Also best in speaker boxes.

Greg