Replies

1. 
   Riversong | Mar 15, 2008 11:25pm | #1

   Where are you located (what's your climate)?

   What is the basement space used for?  Conditioned living space?

   How far does the foundation extend above grade?

   And, if you're talking about using asphaltic (tar) coating for water-proofing - don't, unless you're in very dry soil.  It's at best damp-proofing.  For waterproofing, you'll need a cementitious material like Thoroseal or a paint on finish like UGL Drylock latex masonry sealer.

   If the blue-board (yes it comes in T&G) rests on the footings, then it can be held in place with dabs of a foam-compatible adhesive (such as PL-300) pending backfill, and it doesn't require taping. 

   If the foam is going to extend above grade (which is where most heat loss will be), then it needs to be protected from UV and physical damage.  I use surface-bonding cement for a 1/8" thick trowel-on finish (mix with acrylic modifier for extra bonding).

    

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * Consult
   Solar & Super-Insulated Healthy Homes

   
   

   ---

   Edited 3/15/2008 4:27 pm ET by Riversong

1. 
   toycept | Mar 15, 2008 11:34pm | #2

   Thanks for the reply, riversongThe house is in the northeast.
   The foundation extends above ground maybe 8-10 inches.
   The basement will be used for living space... it has a walkout.
   The interior walls of the basement will be studded out with 2x4
   and insulated with R-11 fiberglass... the stud walls will be positioned
   about an inch away from the concrete foundation (so there's an air space).Edited 3/15/2008 4:35 pm ET by toycept

   Edited 3/15/2008 4:35 pm ET by toycept

1. 
   Riversong | Mar 16, 2008 01:37am | #3

   So why do you want to insulate the foundation on the outside also? 

   If you want more R-value, then frame inside with 2x6 or better yet apply 2" of XPS foam board directly to the inner foundation wall and frame with 2x4 inside of that (no space required in this case).  

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * ConsultSolar & Super-Insulated Healthy Homes

2. 
   jrnbj | Mar 20, 2008 10:57pm | #5

   "And, if you're talking about using asphaltic (tar) coating for water-proofing - don't, unless you're in very dry soil. It's at best damp-proofing. For waterproofing, you'll need a cementitious material like Thoroseal or a paint on finish like UGL Drylock latex masonry sealer."probably the last thing(s) I'd use on an exterior backfilled wall---I'm surprised you mention it, as opposed to some of the new drainage plane membranes and polymeric coatings.....

1. 
   Riversong | Mar 20, 2008 11:11pm | #6

   probably the last thing(s) I'd use on an exterior backfilled wall---I'm surprised you mention it, as opposed to some of the new drainage plane membranes and polymeric coatings.....

   I've never had a problem with UGL water-based masonry sealer.  In fact, I used it to waterproof the inside of a site-built compost toilet chamber.

   High-tech isn't necessarily better.  In fact, often quite the opposite.  We're now discovering that rosin paper or 15# felt performs better than housewrap under siding, and I'm certain we'll soon realize the problems with synthetic roof underlayments (which will trap moisture from below).

   The simplest, least costly, and most environmentally-benign option that is effective is always the correct one. 

   Riversong HouseWright

   Design *  * Build *  * Renovate *  * ConsultSolar & Super-Insulated Healthy Homes

2. 
   Billy | Mar 17, 2008 06:05am | #4

   As long as you're in the planning stage, you should read this:

   http://www.buildingscience.com/documents/digests/bsd-103-understanding-basements/?topic=/designguidance/buildingscienceanddesign/below-gradeenclosure/main_topic

   It will answer many of your questions and cause you to look at your project from a new persepective.

   Billy