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Community and Q&A

Upgrading garage insulation

savage6947 | Posted in Energy Efficiency and Durability on

My bedroom is over an unheated 2 car garage. The ceiling has 2 heating vents running 20′ which are not well sealed and show signs of moisture condensing. The 9.5″ joist spaces have wedged in 6″ fiberglass kraft faced insulation. The joist cavities are open to a ventilated soffit at the door end. I’m going to remove the insulation, seal the 2 heating/cooling ducts and use duct wrap their entire length. I’m going to spray 1″ of isocyene foam on ceiling to seal the entire bedroom floor from the garage and then reinstall the fiberglass before reinstalling drywall. The house was built in 1992.

How do I do it better? Where can I get recommendations for doing it right? Should I block the insulated cavity ends of the joists under the bedroom from the ventilated soffit?

My email is [email protected]

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  1. GBA Editor
    Martin Holladay | | #1

    Q. "How do I do it better?"

    A. Use a much thicker layer of spray polyurethane foam.

    Q. "Where can I get recommendations for doing it right?"

    A. Here: How to Insulate a Cold Floor.

  2. wjrobinson | | #2

    When I had the spray rigs at the site, they encapsulated ducts for me, and to this day that has worked perfectly for those ducts.

    Your top notch spray company needs to be called to your home to detail a complete plan. At that time you could arrange to do some of the work to lower your costs. But you need a complete local plan.

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