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

Are two layers of XPS separated by T1-11 OK?

Braden Enroth| Posted inEnergy Efficiency and Durabilityon

I am re-siding my attached heated garage with wood clad siding to match the house. The current siding, T1-11 (plywood siding), will not be removed as I need to side over the top of the T1-11. Because the windows and doors are reset to a plane that matches the house, I need to use two-inch thick strapping over the T1-11. Instead, I am considering adding 1 inch of XPS over the T1-11 and using one-inch strapping. Since the current insulation is 3 1/2 inch fiberglass with one inch of XPS as sheathing under the T1-11, I am concerned if adding another layer of XPS over the top of the T1-11 will cause a moisture problem. Our climate is cold (zone 6) in Wisconsin. Please reply with your thoughts. Thank you.

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.

Replies

  1. GBA Editor
    Martin Holladay||#1

    Braden,
    I don't think that your plan will cause any problems, as long as you pay attention to your flashing to manage exterior moisture (rain).

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |