Author Topic: Insulation- airkrete  (Read 1735 times)

Theobat

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Insulation- airkrete
« on: February 23, 2016, 11:03:22 AM »
Our 50s era split level home's lower level is not insulated (we live int he Midwest U.S.).  There isn't really enough space for batting.  There is some anecdotal information about off-gassing from spray foam causing health issues for residents.

Does anyone here have any experience with airkrete?  If that's not a good option, do you have other recommendations.

Thanks!

homestead neohio

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Re: Insulation- airkrete
« Reply #1 on: February 23, 2016, 11:42:44 AM »
We retrofitted our very old home which had no insulation.  Our home had air leaks like you wouldn't believe.  We found a contractor we liked who recommended spray foam insulation on the roof deck and air-krete in the walls.  Work was done in 2015 and we're thrilled with the results.  Air krete doesn't expand like PSF, so it doesn't blow your walls apart if installed in existing cavities.  About PSF odor, you have to be careful with spray foam installers as getting the mix wrong for the application conditions can have disasterous consequences.  Our contractor got it right and there was no odor about a week or two after install.  We used to see temp drops of >20 degrees inside our home overnight once the woodstove went out.  Now we see temp drops of 8 degrees, and we burn a LOT less wood. 

Installation of either of these products is a mess.  Air krete cleans up easier than spray foam.

We were unable to find a lot of others who had air-krete installed.  We got a few references from our contractor's prior jobs, but it is not a super common material.  It has been around a long time (found promotional materials from the 1980s), though, and does a good job of getting in all the little air gaps. 

The stuff is friable and relies on the structure of the cavity in which it is installed for it's strength.  Don't assume you can install it in walls, then later remove sheathing and expect it to remain in place and undamaged/effective. 

Be sure to handle any planned wall penetrations (we added a range hood and relocated a dryer vent) or exterior wall wiring upgrades prior to install.

I don't know what part of the midwest you are in, but if NE Ohio, I can PM you the contractor I used.

Theobat

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Re: Insulation- airkrete
« Reply #2 on: February 23, 2016, 11:52:20 AM »
That's great info thanks!  We're outside of Chicago.  Did you take down the interior walls before you installed the airkrete?

homestead neohio

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Re: Insulation- airkrete
« Reply #3 on: February 23, 2016, 01:15:56 PM »
That's great info thanks!  We're outside of Chicago.  Did you take down the interior walls before you installed the airkrete?

No.  That is one of the big advantages of air krete in renovations, leaving walls in place.  My installer removed wood clapboard siding (2 pieces at the top of each wall, some additional to get under windows and above doors), drilled holes in the sheathing about 2.5" diameter, filled with air-krete, installed a polystyrene plug in the hole, then re-installed the siding.  I asked for a quote where I removed and replaced the siding and it was only a couple of hundred dollars less, so I let them do it.  We had so much else to do with other projects that I needed that time.  I used an Angie's List coupon to get $250 off the total price anyways.  The installer wanted warm, dry days for air-krete install.  It goes in wet like shaving creme and sets up hard once it dries, but it dries in the cavity.  To give you an idea of how well this stuff gets into small gaps, it got into the electrical boxes through the gaps between the wires and the box openings.  One wall had old wiring with no ground and they had to turn off a breaker because the installer (outside the home) kept getting shocked.  Apparently it is a good electrical conductor when wet, and an insulator when dry.

Another benefit of air-krete is apparently mice don't like it.  I found some fiberglass bat insulation in one wall prior to insulating.  We thought there was no insulation but apparently the bathroom had some insulation added during a remodel once upon a time.  The stuff was serving no purpose other than rearing large families of mice.

We DID have to tear out the knee walls and ceiling upstairs for them to apply the PSF to the roof decking, though.  That stuff will blow your ceiling or roof apart during expansion.  It is really a great product for air-sealing, though, and the closed cell has the highest R-value per inch available, which is why we needed it.  Our sloping ceilings had 4.5" to stuff insulation, and we got R20 or R25 in there.  They recommend R-60 for attics.  That demo was a gigantic mess.  There was some old cellulose in the sloping ceiling area, so it was like walking around in a giant mouse nest upstairs.  We cleaned it up with snow shovels.  I spent $20 on dust masks that week, best $20 I ever spent on home improvement.

Theobat

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Re: Insulation- airkrete
« Reply #4 on: February 25, 2016, 01:26:28 PM »
Sounds great thanks so much for your reply!