[Greenbuilding] [BULK] Perimeter foam insulation

[Lawrence Lile]

Thanks Kieth!

>But you also mention that it's only a 2" x 9" strip of insulation. 
Ground temperature closely follows air temperature for the first few 
feet, so you'd really have to go down further than you are, I think.

Yeah, there is 2" foam down to 36" below grade, it's just that 6" strip
at the top that is uninsulated. Frost line is about 30" here.  Of course
that 6" exposed concrete is also the strip that is exposed to the
coldest temperatures.  That's the area I'm trying to figure out a good
way to insulate temperarily each winter.  

I pulled out the foam boards last weekend. I believe that a few handfuls
of sand at each joint will hold the assembly tight to the building.
Foam is fragile, and gets worse on exposure to sun.  It would be nice to
have an insulating material (or assembly) that would hold up a little
better.  

Whatever you attach to the building, be it roxul, foamglass, or what
have you, will be come a highway for termites, because they will just go
underneath it. 

Yes it is quite likely that this exposed concrete strip, and my windows,
are the largest heat loss in the walls by far.  I'm focused on getting
moveable insulation into the windows by next winter.  

A friend of mine is recommending installing insulating "wings", dig down
a foot or so, and install 2" foamboard laid flat, 4' or even 8' out from
the wall.  This trick is used in some solar designs

http://www.thenaturalhome.com/frostwalls.htm

To maximize the amount of mass in communication with the house.  I am
beginning to wonder if this mass would accomplish anything at all.  Mass
inside the house, like a fireplace or a jug of water, can exchange heat
with the house better than mass buried underneath.  

 
 
Lawrence Lile, P.E., LEED AP
-----Original Message-----
From: greenbuilding-bounces at listserv.repp.org
[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Keith
Winston
Sent: Sunday, April 22, 2007 9:39 AM
To: greenbuilding at listserv.repp.org
Subject: [BULK] [Greenbuilding] Perimeter foam insulation
Importance: Low

Lawrence,

I think there are a couple problems with your experiment, but it's a 
great first step. As others have noted, I think you'd need to give more 
time for things to equilibrate.

But you also mention that it's only a 2" x 9" strip of insulation. 
Ground temperature closely follows air temperature for the first few 
feet, so you'd really have to go down further than you are, I think.

Also, concrete is a pretty good conductor: I saw once where a relatively

thin strip of exposed foundation can allow something like 1/2 of all the

heat that could be transfered through the wall. I can't find the link 
right now, it had to do with a brick fascia in front of a block wall, on

a ledger -- it was insulated behind, but not under the brick courses 
themselves. I actually tried to convince a mason to do a fascia on top 
of insulation, and he wouldn't even consider it (which I understand)... 
So any exposed concrete outside will be a big problem, and also 
conduction across the floor might be a problem.

Just some thoughts. Good luck.

k
> Message: 3
> Date: Mon, 16 Apr 2007 16:17:13 -0400
> From: "Ted Inoue" <tedinoue at gmail.com>
> Subject: Re: [Greenbuilding] Perimeter insulation (again)
> To: "Lawrence Lile" <LLile at projsolco.com>
> Cc: Greenbuilding List <greenbuilding at listserv.repp.org>
> Message-ID:
> 	<50d688f80704161317k501208f6t58ceb4166eb258a9 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Sounds like the beginning of a good experiment.
>
> I would think that you'd need to do a longer term run, like perhaps a
> month or two at the start of winter to give the thermal mass time to
> equilibrate more.
> I'd also be concerned about air and water tightness of the insulation.
> I'm always skeptical of the effectiveness of laying foamboards agains
> walls. But this would be good experiment to see in practice how well
> this practice works.
>
> On 4/16/07, Lawrence Lile <LLile at projsolco.com> wrote:
>   
>> Here is Yet Another Rehash of the perimeter insulation problem:
>>
>>
>>
>>     


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