[Greenbuilding] [BULK] Re: [BULK] Re: PEX tubing

[Lawrence Lile]

That brings us to the edge of the Concrete detail.  
 
We ran, as you indicated, the PEX tubing about 2-3 feet away from any
exterior edges of the concrete slab.  I left 9" of the exterior edge of
the slab expose all the way around the house.  This is a major energy
nosebleed, but necessary in termite country. 

Below that, the outisde wall footing is insulated with 2" foam down 36"
below grade.  Sand is backfilled in the top 6" against the top edge of
the foam, because termites don't like sand much.  There are specific
grades of sand that termites cannot tunnel through - although they are
expensive if I ever get an infestation I can replace the regular sand
with that stuff.   

I've imagined putting movable insulation in this gap only in winter, I
looked into foam glass insulation for the gap, which termites can't
tunnel through (but they can go under it),  but so far I don't have a
good solution.  

I wonder if this gap is really such a large energy leak?  I don't have
much of a way to tell.  

I did not insulate under the slab.  This causes a larger mass (soil) to
be included in the insulation envelope of the house.  I am wondering
about the wisdom of this now, it takes a long time to change the
temperature of this massive slab and soil underneath, which translates
to a lot of energy use in the early weeks of heating the house.  


 
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 Chris
Green
Sent: Sunday, January 21, 2007 3:36 AM
To: Greenbuilding at listserv.repp.org
Subject: [BULK] Re: [Greenbuilding] [BULK] Re: PEX tubing
Importance: Low

Bruce Donelson wrote:
> The tubing is pressurized as soon as it is installed to check for
leaks or
> damage. Also you might hear escaping air if it is cut. Keep pressure
in it
> through framing as well. Framers can shoot into tubing when fastening
down
> walls. Best to run the PEX through doorways, not under walls. But
sometimes
> doors move duriing framing....
> Bruce Donelson
>   
When I installed the interior framing in a 3,500 sq. ft basement with 
tubing in the slab, I set the walls in place then ran a bead of glue 
along the edges of the bottom plate, sort of like caulking around the 
bathtub. This held everything in place surprisingly well, as I found out

when it was later decided to remove one wall entirely.
I had to plane off the glue and broken slivers of wood left behind with 
my widest and best quality  chisel... :-(

The walls near the foundation were safe to spike in place since the 
tubing was either one foot or two feet from the exterior walls. This was

good because we needed to seal the poly to the concrete here with a 
tarry looking sealant. (disgusting stuff that never hardens, AFAIK, but 
tends to ruin your clothes....) We drilled a series of holes (1/4", 
iirc) in the bottom plate then drove in about three nails in each hole, 
the wedging action holding everything securely.

The glue was probably something like Bulldog PL 600, an exterior grade 
that's extra tough. I realize a some people would prefer to not use glue

if there's an alternative, but this is a trick to keep in the memory 
banks just in case...

Cheers,

Chris Green.

 


>
>   


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