GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

New Home Build (Zone 6)

sxv201 | Posted in Green Building Techniques on

We are planning a new build next spring in zone 6 –Ottawa, Ontario, Canada

2 questions:

1. Structure –can I use rigid foam insulation (in place of OSB or plywood for exterior sheathing?) with corner bracing and in conjunction with fibre cement board and some sort of rainscreen (to create drainage)

Frame > Rigid Foam Insulation > Rainscreen > vertical furring strips > fibre cement board

Will this be strong enough structurally to hold up the fibre cement boards?

2. Insulation on this house (as mentioned zone 6)

2″ of XPS rigid foam nailed directly to the frame, with 1.5″ of closed cell spray foam directly on the backside of the rigid foam and studs with another 3″ of blown insulation inside the cavity of the wall (with no vapor barrier, right?)….gives me about an R-value of 29

I would greatly appreciate any comments

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. wjrobinson | | #1

    Stephanie, builder signed, plans designer? Are you going to ask a question here and then tell others how to build your home? Curious...

  2. GBA Editor
    Martin Holladay | | #2

    Yes, it's certainly possible to brace your walls with just a few OSB or plywood panels (usually at corners, and sometimes in the middle of long walls) and to install rigid foam sheathing elsewhere. It's also possible to use diagonal metal L-strapping for bracing your walls, and to use just foam sheathing -- as long as the bracing plan is approved by an engineer and your local building inspector.

    Here's an article that provides more information: 4 Options for Shear Bracing Foam-Sheathed Walls.

  3. user-723121 | | #3

    This wall is too complicated, foam sheathing, spray foam on the back side of this and also blown insulation? Consider a double wall of 10 inches or so with a blown blanket insulation.

  4. ultracrystal | | #4

    Stephanie, if you're in Ottawa, checkout Tartan homes. I believe they are bracing their walls with minimal/no OSB sheathing. This would give you an idea of what local inspectors are passing at least.

    1. Expert Member
      MALCOLM TAYLOR | | #5


      Stephanie posted the question in 2012. If she hasn't chosen a sheathing by now she has a lot more pressing problems to worry about.

  5. Deleted | | #6


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |