Insulation a thin wall (block)

homeboundNovember 26, 2012

I'm involved in a water damage repair involving replacement of soggy drywall and insulation (little mold). These same outer walls, one above the other have turned out to have extra thin cavities (3/4 furring over block on the upper two floors, and 2x4 studs turned on their side on the lowest floor, which is partially below grade.

We replaced about 4 to 8 linear feet of water-logged lumber on each floor.

Building thicker walls is not in the cards, so what can be done about the insulation? I am considering 1 1/2" xps in the basement floor cavities, cut to fit, with all gaps foamed. On the upper floors, I only have 3/4" depth, which means same thing, but with 3/4" xps. Then I'm going to foam all the gaps. No other vapor barrier, then close it up.

Thoughts on this plan of attack?

Thanks much.

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tjdabomb

Use double-bubble foil-wrapped insulation.

http://www.radiantbarrier.com/double-bubble-insulation.htm

Works great, easy to install, and best of all, if installed in layers with an air gap between each piece, the R value is multiplied. Call them, they can give you the R values.

I install this everywhere - no mask or eye protection necessary like with pink.

    Bookmark   November 27, 2012 at 12:40AM
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energy_rater_la

3/4" two layers for upper floor with staggered seams
then install sheetrock screwed to 1x's. use highest
R-value foam sheathing.

plan for basement..stays as you described.

foil bubble foil is a waste of money & effort to
installed. little to no R-value it is about emissivity.
even as a radiant barrier correctly installed in an
attic in a hot climate..there are cheaper products
that do the exact same thing for 1/4 of the cost.
foil bubble foil is all hype and little real world
savings.

what was the source of moisture intrustion that
caused original problem?
no sense in moving into reno until that issue
is resolved.
(although I'm sure you know this homebound!)

best of luck.

    Bookmark   November 27, 2012 at 11:32AM
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tjdabomb

"foil bubble foil is a waste of money & effort to
installed. little to no R-value it is about emissivity.
even as a radiant barrier correctly installed in an
attic in a hot climate..there are cheaper products
that do the exact same thing for 1/4 of the cost.
foil bubble foil is all hype and little real world
savings."

What FACTS are you using to base your statement??

There is very little effort needed to install it - you unroll it and cut to size with a razor - the same effort needed for a foam product, and, it is bendable,not breakable like foam and leaves no waste (foam pieces).

Cost?? What material do you prefer and what is the cost? Double-bubble, pre-cut 500 sq ft. cut to 24" (for rafter installs) is $162 delivered to me. What is the cost of your product???

What is the R value of your product? Double-bubble stacked x3 with 1/2" air gap = r50. This is FACT.

What is the fire rating of your product? What is the resulting carcinogens in fire tests of your product?

Homebound - I don't work for innovative insulation, I just use their products effectively over a long period of time. If you want facts and not baseless conjecture, call them, ask for a salesman or Dan (the owner) they are more than willing to back their products.

    Bookmark   November 27, 2012 at 5:37PM
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homebound

Thanks for the comments.

The source of water was a damaged scupper on a flat roof. They just had it repaired and reroofed.

I'm in the midst of cutting and installing xps.

energy_rater_la,
I'm not quite following you regarding the upper floors. Are you saying to add another 1x onto the existing furring, then double up xps (staggered) in the cavities?

tjdabomb,
I scanned that site briefly. I wasn't planning on double-furring, so it didn't seem to make sense. And for single-furring, they recommended their white product, but never seemed to mention the R value for that application - thermal break and moisture barrier, they did mention. Anyway, thanks for the link.

Thanks much.

    Bookmark   November 27, 2012 at 6:40PM
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energy_rater_la

no.
put the 1st layer xps between furring strips already there.
then put another 2nd layer that will cover both the layer
of xps against the block & furring strips.

when installing drywall use longer screws and
screw thru drywall, top layer of xps & into furring
strips.
then you'll have the layer against the wall
installed inbetween strips, and another
layer of 3/4" xps on top.
this will give you as much as in basement.

not suprised you didn't find R-value.

tj..for my radiant barrier in the attic..where
the work in hot climates, I paid .05 per sq ft.
single sided fsk radiant barrier.
this is my material of choice. not much sense
in paying more for a more expensive product
that works just the same as single sided product.
what sells the more expensive product is hype.

I'm very pleased with radiant barrier in attic
in my hot climate. reflects the heat nicely
the actual insulation on the floor of the
attic is what keeps attic temps in the attic.
not the radiant barrier.
the radiant barrier has minimal R-value. its value
is in emissivity.

even with 4'x8' sheets of iso board ( R-7 foam
with foil facing) I can cut with no waste.
tape measure, tsquare razor knife. no problem.
oh and I get actual R-VALUE.

Double-bubble stacked x3 with 1/2" air gap = r50. This is FACT.
no its sales hype. if you find R-value of foil bubble foil
wrap..please post it. just not from mfg selling the product,
a site where the info is unbiased.

I'm not the only person to know this is true.
those scam artists come out every year taking advantage of
older people with RB rolled over insulation in attics.
scam. scam. scam.

http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/29497/The-Foil-Faced-Bubble-Wrap-Sham-Understanding-Radiant-Barriers

read the comments Kvalue folks strike again! LOL!

    Bookmark   November 27, 2012 at 7:12PM
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tjdabomb

http://www.nasa.gov/centers/johnson/home/get_green.html

One hand, NASA engineer, other hand, who???

"older people with RB rolled over insulation in attics.
scam. scam. scam. "

The only scam is the installer - if you don't install it correctly, it doesn't work correctly. Kinda like changing your oil and putting the oil filter in the glove compartment! LOL!

    Bookmark   November 27, 2012 at 8:02PM
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energy_rater_la

from the nasa article
" The biggest change, Flahaut said, came from the new air conditioner"
Radiant barriers in attics are great.
but it is the whole house approach that saves money
& energy.

with the oversell of low emissivity products you
get stuff like this:
http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-paint-salesman-tripped-his-own-product

cutting off his nose to spite his face.
on one hand I admire his faith in the product.
but on the other hand am laughing about how
misplaced his faith is.

this the article that preceeds the one linked
above. just fyi
http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-paint-merchants-dupe-gullible-homeowners

you have to admit..some of the claims
are outrageous.

    Bookmark   November 27, 2012 at 9:43PM
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homebound

I'm trying to comprehend why would one need a radiant barrier for a basement wall application without a radiant heat source (or much of one) to reflect down there? This is aside from any secondary benefits that it might provide, i.e. moisture barrier, etc.

On the other hand, this might inspire me to add some aluminum foil behind our radiators upstairs.

    Bookmark   November 28, 2012 at 5:38AM
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energy_rater_la

misuse of the product.
not understanding application.
hype.

    Bookmark   November 28, 2012 at 8:38AM
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alan_s_thefirst

I like Isoboard, especially the stuff with the foil on it - it can act as its own vapour barrier.

You could also use a layer or two of isoboard without the foil, since you shouldn't double up vapour/air barrier, then a layer of the mylar foil bubble stuff, which (I don't know if it's certified as such) could be your air/vapour barrier. Of course, you couldn't use it under drywall - too springy - so you'd have to use it between the furring strips, with regular vapour over the furring strips, and taped.

    Bookmark   November 28, 2012 at 4:10PM
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tjdabomb

from the nasa article
" The biggest change, Flahaut said, came from the new air conditioner"
Radiant barriers in attics are great.
but it is the whole house approach that saves money
& energy. "

"Miller spent about $250 on supplies for his radiant barrier � four rolls of barrier and one staple gun � and installed it himself over two days in December of 2005. The following summer, his electricity bill showed that he used about 6 percent fewer kilowatt hours than he had in previous summers, with a correction for the difference in average temperatures included in the calculation. Based on that, he determined that he saved $119 in that first summer, alone. By the next summer it was paid off, and last summer the difference was pure savings. "

Two NASA engineers, two separate installations with both installations requiring different means to an end.

I bet those astronauts were sure happy with their foil suits when they were in temperatures that ranged from 250 �F above to 400 �F below zero Fahrenheit. This feat in temperature control technology enabled the astronauts to work inside the Apollo Command Module wearing short-sleeve shirts.

Gotta love those short-sleeve shirts!!

    Bookmark   November 28, 2012 at 7:33PM
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jagans

You want to use EXPS not XPS. Either Styrofoam by Dow Chemical or Foamular by Owens Corning. They have an R value of 5 per inch of thickness and they are anti hydrogenous. You could use "Stuff" the isocyanurate in a can to seal openings. You should put a 6 mil Poly vapor barrier on the warm side, which is probably on the inside. staple this temporarily and then screw your drywall to the studs, furring strips. This is OK but it is still not much insulation if you are in a cold area. Good Luck. Two layers of 3/4 inch with staggered joints is always better than one layer of 1.5, but if you are just cutting between 2 x lumber on the flat it wont make much difference. You could install a second one inch layer over the nailers and the infill insulation and screw through it to the nailers, as it has good compressive strength. About 40PSI

    Bookmark   November 29, 2012 at 6:12PM
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energy_rater_la

would you need to poly vapor barrier?
seems to me that the foamboard would work
as long as seams are staggered & taped.

my climate is hot humid, so interior vapor
barriers aren't something we do here.

just curious.

    Bookmark   November 29, 2012 at 8:30PM
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homebound

Sorry to revive this post, but this scientific review seems to do a fine job of explaining the science behind radiant barrier usage.

My takeaway is that it might only be worth it in attics in warm climates and properly installed, but that's about it. Certainly not in wall cavities where you would need to sacrifice some cavity space to create the necessary air gap in front of the foil face.

Here is a link that might be useful: Alaska paper

    Bookmark   December 19, 2012 at 9:50AM
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