basement wall insulation

[calvert]

Insulation Panels | InSoFast - Engineered Simplicity
www.insofast.com/

Anyone have any experience with these? I am thinking of using these on an upcoming job to save space and framing labor.

If you have not used them but care to comment on any possible concerns, please do. Thank you.

[worthy]

Two inches of EPS does not meet IECC 2009 or 2012 for basement insulation in Zones 4 and up.

Furthermore, depending on the climate, 2" of EPS is so vapour permeable that more mechanical dehumidification will be necessary than with other insulation materials and systems. (Admittedly, this is the owner's problem, not yours.)

There is also a requirement in some jurisdictions that the insulation be mechanically attached. And even if there isn't, adhesive is often inadequate on poured walls due to all the irregularities in the walls at the form edges, corners and tie holes. So you'll be anchoring it with concrete screws etc. If you're doing that, it's a lot easier to work with 4'x8' foam boards than these proprietary panels.

Unless you're using surface-mounted wiring, electrical boxes have to be mounted directly on the foundation wall--big thermal hole in the insulation.

I've finished a number of basements in new homes and old. In my cold climate, I use either XPS or CCSPF on the wall, followed by fibrous insulation between the framing, either light metal or dimensional lumber.

[m beezo]

saw it on This Old House and looked a little intriquing. Will look at the site to see if it has been approved for my area and may consider it for my home.
As to the insulation value not being enough it would much better than most basements.

[Mark Parlee]

Calvin
Thanks for sharing that; it does look like a cool system at first blush. I am sure it does not go on near as slick as shown on the show and I would like to have been there for the entire production to hear the problems addressed.
Worthy brings up some very good points to consider; I too use the method he describes regarding the XPS with the framing set out in front. I can then address anything that needs to go in the wall.

[calvert]

Worthy, I spoke to a rep. of the company about the code issue as this was my first concern. He said that the "system" R-value which of course includes the drywall, air films, etc. performs to code requirements (10 or higher) for continuous surface insulation applied in my climate (zone 5). He also said they have submitted documents to code officials when they have questioned performance issues and have routinely been accepted as meeting the requirements.

I, having been involved with the sales and specifying of insulation systems for 30+ years, have used all types of materials and approaches in basement applications. As you and Mark have noted, cc spray has been high on my list.

This particular job got me thinking about the issue of perhaps having too good a vapor barrier on the interior basement wall. This is a 20 year old vacation home on a lake. The light aggregate block walls are nearly buried full depth except for a very small section of walk-out wall.

The lot, at least where the house is, is nearly flat and adjoining lots slope gently to this lot. The basement doesn't have a history of water seepage but I also cannot determine what waterproofing was done (or not) on the exterior.

My fear is that with exterior grade coming nearly to the sills and utilizing a non permeable interior insulation, I don't want to force "rising damp" to the sills. Keep in mind that we have very limited drying potential to outdoors due to the fact that grade is so high.

Many years ago I remember a home that was experiencing high levels of RH and as I eliminated possible sources I was left with the determination that vapor migration across the block foundation was our culprit.

I had fire retardant poly installed over the block and sealed the bottom and top very well. The home also had a high grade (1 foot and less exposed) around the entire perimeter and my concern then was that the exterior parge would spall if enough moisture collected in block during cold weather. I warned the homeowner of that concern. The interior RH problem was most assuredly resolved. The first few years after the interior barrier was installed I drove by the home to see what was happening and the parge did indeed show significant scaling.

By the way, I did have Dr. Joe of BSC (before he wore suits) at that house before we installed the poly and there was a discussion of "above grade" moisture migration. I believe that now he recommends an above grade exposure of approx. 2 feet to allow for migration to take place if there is a non permeable interior insulation used...and that is a determination that might be very site specific relative to soil and moisture conditions as well as foundation and footer waterproofing techniques employed.

Of course that may only apply where winter conditions can lead to spalling issues but certainly as I see new homes being built today I observe many circumstances where grade is too high, certainly higher than code recommendations and I am sure the issue of permeable basement insulation perhaps needs to be looked at a little more carefully under certain circumstances.

[worthy]

Insofast's EPS provides an R Value averaging 4.45 per inch. Add to that the R Value of the drywall .45 and the inside air film R.68 and the panels reach 10.03, meeting the IECC 2009 standard, which has been adopted by the Commonwealth of Pennsylvania. They do not meet IECC 2012 which bumps up the requirement to R15.

Query, does the Code allow the inclusion of drywall, air film and paint to be used in calculating R Values.

Under the Code I build under (Ontario Building Code, 2012) basement walls must be generally insulated to a minimum R20. (Depends on the compliance package you choose.) And this refers to the insulation only, not to air films and the like.