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

Attached garage below grade

Yoni_Green | Posted in General Questions on

Our 1925 house in Zone 5 has a below grade garage that is attached to the house. I have attached a side view of this part of the house. The house has a lot of energy inefficiencies due to this design. 

Should I air seal the gaps under the kitchen floor? If yes, there are some fairly large holes (see pic). How should I seal these holes?

A related question, should I add insulation above the garage roof, including under the kitchen floor? If I do, should I air seal it with spray foam before adding batt insulation?

I appreciate your responses. This forum is one of my favorite places on the internet. 

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. walta100 | | #1

    Seems to me the smart move would be to repurpose the space for anything but a car.

    Today’s fire code would require fire rated walls, ceiling and doors for such a space today.

    Two layers of drywall with staggered and taped seams would be a good air barrier

    Walta

  2. Expert Member
    MALCOLM TAYLOR | | #2

    Yoni_Green,

    The two priorities are:

    - Creating a fire separation between the house and garage. This is as simple as using 5/8" drywall on the walls and ceiling.

    - Air-sealing between the garage and the house. Mainly to keep the exhaust out, but it will also improve energy efficiency. I wouldn't worry too much about the holes in the sub-floor above. Insulate the rim joists with foam board, and air-seal them with canned foam. Fill the joist spaces with batts, and use the drywall as your air-barrier.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |