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Fire Separation in Garage + Moisture

Brinkman | Posted in Building Code Questions on

This is part building code question, part moisture question. I live in a house built in the 1920s, with an attached garage that was built sometime in the 80s (I think). I live in western Wisconsin. When I moved in, the inspector said the little attic space in the garage needed to be closed off as a fire block. However, I feel like doing that would be asking for moisture issues in that space. It’s not vented, underneath the space in question is my kitchen. More details on this space…

 
The house is a T shape, and when they added the garage, they created a bonus space that’s about 4 feet by 12 feet that was incorporated into the first floor of the house. The second story of this space remains open to the garage. The joists are filled with fiberglass batts with blown-in cellulose over top. It’s this attic space that’s the space in question. Do I enclose this attic space, thereby separating it from the garage? Or is it fire separated enough as is? 
 
I’m attaching pictures of the house. The bird’s eye image has the garage on the south side. I tried to put a red rectangle around the spot in question.

Then the other pics are from inside the garage, and looking at the “attic space.” The wood and black paper walls in one of those pictures are the formerly exterior walls of the house. Now those are in the garage. Thoughts?

 

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Replies

  1. Expert Member
    MALCOLM TAYLOR | | #1

    Brinkman,

    You never want your house and garage connected like that for two reasons: Fire and the contamination of the living areas by vehicle exhaust.

    The easiest solution is to drywall the garage ceiling with 5/8" rock, then install adequate roof venting for the whole area above. That is typically located at the soffits and near the ridge, but if installing soffit vents is too onerous, you can compensate by adding more near the ridge, or on the gable ends.

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