Foundation / Basement Insulation

[Rich]

So as we all know there is a right way and a wrong way to do just about anything. This topic is in regards to the right and wrong of doing basement/foundation insulation. There are 2 different ways to insulate as many know - interior and exterior of foundation. With each there is a right way to do it. Buildingscience.com has a method http://www.buildingscience.com/resources/foundations/conditioned_crawl.pdf that includes mechanical systems, vapor barriers, insulation, etc. There is another on toolbase.org with similar - but not quite the same.
Please post any methods, white papers, etc.. that can lead us to enlightenment on this subject :) Is what I want to do is literally get every resource possible on the subject and start disecting it - and possibly come up with a system that will work for each climate area - arid, humid, etc..

[danh]

Why would I want to do that as opposed to insulating the underside of my floor? Wouldn't that add a whole bunch more area for my HVAC system to condition?

[Rich]

I didn't write the paper but I think this is the basis of the point they're trying to make

Conditioned crawl spaces perform better than vented crawl spaces in terms of safety, health, comfort, durability and
energy consumption. Conditioned crawl spaces also do not cost more to construct than vented crawl spaces.
Existing vented crawl spaces are experiencing serious moisture and mold problems and are costing builder’s and
homeowners significant resources to repair. Despite the obvious problems with existing vented crawl spaces and the
obvious benefits of conditioned crawl spaces there is not a significant trend towards the construction of conditioned
crawlspaces. One of the reasons typically cited by builders and designers is “the code does not allow me to build
unvented crawl spaces”. This is both generally correct and misleading. The model codes do not allow the
construction of “unvented” crawl spaces – except in very limited circumstances, but they do allow the construction of
“conditioned” crawl spaces. The distinction is important and necessary. Four conditioned crawl spaces were
constructed and monitored over a 12 month period. The data is presented and used to support the current code
requirements for the construction of conditioned crawl spaces.

[myron]

I agree that a heated unvented crawlspace is the way to go.

I have a question on basement frost wall insulation.
I recently had a building inspector tell me the batt, fiberglass insulation had to stop a minimum of 6 inches above the slab. 6 mill poly and drywall going on walls. His reason was you had to let heat in the bottom of the wall to melt the forming frost off the inside of the foundation. He said if you didn't you would get a tremendous amount of ice forming on the inside of the foundation, which would melt in the spring and cause water damage.
To me this is silliness.

Anyone have thoughts on this, or ever heard of it before. BTW I'm in Ontario.

The only reference I can find to this in the OBC is in a crawl space where ground water may rise and damage the insulation, then the insulation must be 6 inches off the ground, that makes sense, but not in a heated finished basement.

Thanks for anyones thoughts

Myron

[bkrahmer]

That sounds like silliness to me as well. The only place where frost could form on the inside of a basement wall is about 6 inches above the frost line. Below that, the ground will be a minimum of 32 degrees.

[roger g]

HIS reasons mean squat! What does the code or the local code say? His ONLY job is to enforce the rules, not make them. Of course easier said than done.


roger

[rbisys]

Greetings,

Gee Roger G you run into those types too, do you. Just love them. They know all there is to know about something they know nothing about. If the inspector was really shapr he'd ban fiber glass in crawl spaces, not to mention the rest of the house. Reminds me that I was in contact with the Illinis enegy dept. They will not help subsidize solar homes insulated with FG. God, a ray of hope?

Back to serious. I developed a method to insulated crawl spaces with radiant barriers that works better than anything else I've seen in 30 yrs.

If you want a copy of the install drawing and the mfgr to get the material from, e-m me. With radiant barriers there is no condensation or mold problems.

If you go with basement, 3' 1.5 # foam, T&G for walls and floor.

If you insulate the house with RB I have instructions on how to build a VERTICAL ground temp cooling sys. Not geothrem, only a small water pump. You have to be abe to augar 15' down from surface.

Cannot be used with low eff insul such as FG, Cel or foam.