[Greenbuilding] air krete

[Stephen Collette]

Why yes I have had experience with Air Krete. I've been thinking  
about posting this experience for some time now and well it's more  
fun to post than to do work, so here we go.

The air krete was recommended by an energuide auditor for this 1940  
brick home in Peterborough for a MCS woman that I was dealing with.  
The walls were hollow, and there had been several dozen issues with  
this house. She was hooped into buying a mouldy drafty, dusty smelly,  
asbestos insulated house when she is hyper sensitive. I came in after  
the fact to help out. It's been a year now.

Anyway it was recommended to fill the empty wall cavities with Air  
Krete as it is magnesium oxide and a relatively inert product and she  
shouldn't react to it. They installed the product on the outside  
walls so that the indoor air would not be affected. I was not present  
during the installation, however a general contractor that I had  
brought in was.  He was working on the inside during the installation.

The first thing that he could hear was the sizzling around the  
outlets. Like electrical sizzling. He even recorded it with his  
camera on video mode. Yes it is the sound of water and electricity  
inside her walls. Around here that noise is generally frowned upon.   
The next thing that happened is the dining room wall expanded into  
the dining room. Yup into the dining room. Massive pressure cracks  
across 10 x 10. Then in the living room after the full stop, heaps of  
swearing and orders to get their act together, they proceeded to make  
an even bigger split under the window. Another full stop, way more  
language and they left with orders not to return until they knew what  
they were doing.

So they did come back, the GC took care of all of this, but kept me  
up to speed.  So they were also making quite an astounding mess  
outside. Like dripping air krete everywhere all over the brickwork.  
They were told to clean it up and when they came back they did with  
acetone. Yup acetone on a MCS woman's house. We told them like 100  
times that everything had to be cleared with her prior to proceeding.  
So now the acetone did clean up the air krete, and it also soaked  
into the pourous brick. So now in the sun for weeks later it off  
gassed the acetone, making it impossible for her to open her windows.

So they were in a fairly heated discussion over who was paying for  
what and all that stupidity and it went all the way to the top of air  
krete.

So then since we knew they obviously installed it wrong, the concern  
was whether it had actually cured in the walls or not. Turns out it  
didn't. Here is where it gets really interesting.

The wall system is a roughed out 2x4 hollow with one of the original  
types of drywall boarding installed. The foil backed drywall in 16" x  
8 lengths installed with the 8' bit horizontal. So this foil backed  
stuff and brick on the outside causes a bit of an issue for a product  
that is trying to dry. It can't shed water into the wall board, since  
the wallboard can't take it. So where does all the water go, long  
time drying?  Well into the studs of course. After 4 months the  
moisture content of the studs were 50%. Yup that much.

Apparently the air krete won't grow mould. I'm not particularly  
worried about the air krete growing mould. I'm worried about the  
woody bits growing mould.


All of this is an interesting issue, and I'm not sure that Air Krete  
the product is the issue. These spray in foams especially in a  
renovation situation, really need to be assessed as to how they will  
work in the given wall system. Are all wall systems that use spray  
foam have saturated studs like this house? Who checks? People on this  
listserve maybe, but beyond that, if you don't know there is a  
problem, would you check? This insulation will take until summer to  
be completely dry versus the regular couple of days. The company is  
not helpful, and this issue is not yet resolved since October, which  
is sad really. I myself think magnesium oxide has some great  
properties and is a really interesting material to build with. If  
this does pull away from the studs, then what would happen to this  
wall system? Full failure or dry out? I don't know. Neither does my  
client, nor actually the company, or if they do, they are not telling.

So if you are going with a spray foam and even Air Krete, do your  
homework on the installers as well as the product. Call references.  
This stuff is messy, don't let that little detail be overlooked.  
These guys it turned out had done other spray foams, but not this  
one. Too bad, as they won't have another chance to do it again, as  
Air Krete rightly so pulled the franchise on them.

I would also like to know about other biodegradable insulations that  
would work. I've seen soy and air krete and they both have potential.  
Anyone else have any experience I too would like to hear about it.

Thanks for listening to this rant.

Stephen

Stephen Collette B.B.E.C
Principal

Your Healthy House
Indoor Environmental Inspections & Building Consulting
www.yourhealthyhouse.ca
stephen at yourhealthyhouse.ca
705.652.5159


On 12-Mar-07, at 1:00 PM, greenbuilding-request at listserv.repp.org wrote:

>
> Anyone have experience with Air-Krete? I am looking for a  
> biodegradable
> spray on insulation.
>
> I heard that is shrinks back from framing members, and will not  
> stick to
> wood.
>
> Any 3rd party info would be helpful.
>
> Best Energy,
> Joseph Becker
> ION Ecological Building Alliance