[Greenbuilding] Basement Insulation was ICF heat seaks cold

[JAY WALSH]

To understand the cost and energy effectiveness of insulating a basement, take
a look at the Canadian Mortgage Home Corp. report noted below. 
What I like about this report is that both energy and cost of materials are
considered in the various insulation approaches. Note that the study looked at
insulating the walls only and did not include or look at the impact of under
slab insulation. If you’re not a technical person, I would suggest at least
looking over the Conclusions on page 5 of the report.
Economic Assessment of Residential Basement System Options.
January 2007  Technical Series 07-103
http://www.cmhc-schl.gc.ca/en/co  Search - Basement Insulation Study 65346

For under slab insulation look at it this way. 
1. For US climate zones (not planting zones) 5 and above under slab and slab
edge insulation is required by code for walk-out basements and slabs on grade.
If you plan on occupying this space now or later installing insulation at time
of construction is advised.

2. Don’t waste your time putting in radiant heat in a below or on grade slab
unless you plan to put at least R-10 insulation below and at the slab edge. 

3. If someone (concrete contractor or builder) tries to sell you on putting
reflective bubble wrap or Insul-tarp under the slab as effective and
sufficient insulation – look for another contractor. Both these products are
junk. Stick with rigid foam or one of the environmentally preferable products
mentioned by others in this post.

4. If you plan to occupy this space and have gone to the effort of insulating
the walls why stop half way. The additional cost of insulating the slab
amortized over a 15 year home loan amounts to about 50 cents a month. 

Sincerely

Jay Walsh
Energy Star and LEED for Homes Rater
Center for Ecolgical Technology


> Message: 8
> Date: Fri, 16 May 2008 08:22:51 -0400
> From: Norbert Senf <mheat at mha-net.org>
> Subject: Re: [Greenbuilding] ICF and heat seeks cold
> To: greenbuilding <greenbuilding at listserv.repp.org>
> Message-ID: <200805161223.m4GCN2xq014802 at mail7.atl.registeredsite.com>
> Content-Type: text/plain; charset="iso-8859-1"; format=flowed
> 
> At 09:44 PM 5/15/2008 -0400, Robert Tom wrote:
> >(snip)
> >I half agree with Michael -- that is insulate the exterior of the basement
> >walls and under the slab.
> >
> >(snip) If anything,
> >IMO it's detrimental since one is isolating the beneficial thermal mass
> >  from the living space.  (snip)
> >
> >Less commonly used (ie pricier) is cellular glass insulation. It's
> >compression resistance is in excess of 90 psi @10% deformation.
> 
> I agree with Rob.
> 
> I'd check the 10% deformation figure on the 
> Foamglas - it doesn't deform the way
> styrofoam does, as far as I can tell.
> 
> Our basement floor is uninsulated, and stays 
> around 55F +/- 2 degrees, year round.
> If I were doing it again, I'd insulate.
> 
> Our house is 6" CMU's with 4" of foam on the 
> outside. One nice feature is that it has a
> time lag of about a day. It takes about a day to 
> heat up if you let it cool down, and takes
> about a day to cool down if you don't light the 
> stove. I can fire up my woodburning cookstove
> in the summer for an hour or two, and the walls 
> can soak up the heat no problem. Also, it works
> great for night-time cooling in the summer in our climate.
> 
> Norbert
> 
> -------------------------------------------
> Norbert Senf---------- mheat(at)heatkit.com
> Masonry Stove Builders
> 25 Brouse Rd.
> RR 5, Shawville------- www.heatkit.com
> Qu?bec J0X 2Y0-------- fax:-----819.647.6082
> ---------------------- voice:---819.647.5092
> 
>