I'm replacing my siding and find lots of gaps in the fiberglass inulation
(in-wall). I am thinking of adding foam boards to the exterior walls to
better seal them and add little insulation. Going by R-value, this doesn't
add much (1/2" R4) but maybe this would protect better against winds etc. I
am installing hardie plank siding. Will this home 'breath' ?
ventilation? Anyone has experience with this type of insulation?
You won`t get R4 per 1/2" out of any board I know of, R7.2" new and
stabilised at R6+" is the best Polyisosyanurate gets. I covered my
house in 2" polyiso for R 14.4. Can you replace siding on a soft surface
and not over nail it making it uneven? I covered mine in Osb.
I tried just about every brand a few years ago on a west wall I
rebuilt, the blue board won as somewhat effective, the foil covered
white crap is landfill. Only the blue board is only slightly more
effective than an empty space even when fitted with surgical precision.
A poorly fitted R-13 fiberglass did much better. I've ripped most of it
out and replaced it with R-16 fiberglass. The blue has its uses, and I
would use it again, it has the advantage of being softer and tighter so
accurate cuts can be made with out the shattering and crumbling the
white stuff does. Any place the bats will fit, isn't one of its uses.
R value sounds a little high for 1/2", but reguardless these R values
are under 'ideal' conditions. Meaning as you pound down the nails,
the insulation becomes damage. It does seem to help ensure your
building envelope is increased. If you really want to reduce windy
effects, might want to take the time to use a properly installed house
I heard on one DIY show, drafts account for the majority of heat loss
in a home, followed closely by poor insulation.
Do your self a favor and take this time to get some professional
advice. The cost of fuel is ever increasing, and a few bucks to a
professional energy advisor might help in the long run.
Also, follow up with what you did, atleast I'm curious the end result.
tom @ www.FreelancingProjects.com
Actually, the R value for the board I wanted to use, is about 7.2 per inch,
3.6 per 1/2".
I decided to use a felt paper instead of Tyvek. Installing it right is the
Thanks for all replies.
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