DIY Home Improvement, Remodeling & Repair Forum

DIY Home Improvement, Remodeling & Repair Forum (
-   Insulation and Radiant Barriers (
-   -   Repair Insulation between garage and room above (

smitty202 01-03-2011 08:00 AM

Repair Insulation between garage and room above
I have a room over the garage. When my home was built the insulation contractor installed insulation from the garage ceiling side but did not push the insulation tight to the floor above, so there is a small (2-3") gap between the insulation and the floor. This gap extends to the exterior of the house, so the rim joist is not fully insulated. The contractor has agreed to come back and fix this. They have proposed pushing up the existing insulation and blowing additional insulation below that to fill the bay. Anyone have experience with this? Will it work?

handyguys 01-04-2011 11:48 AM

I have a few questions....
1) how do you know there is a gap? Isn't the garage ceiling area covered by drywall?
2) where is he going to blow in insulation from?

Sorry, the way you describe the setup doesnt make sense.

My preference would be just to put in larger batts versus adding fill. Ideally the best solution would be to spray closed cell foam and not use batts or loose fill.

smitty202 01-04-2011 06:59 PM

The floor is very cold, so I cut some holes in the garage ceiling and moved some insulation to look. Also, there are knee walls on each side of the room, so I cut a hole in the empty space and saw the gap there.

He intends to blow insulation in from the garage side, drilling the holes, pushing up the existing batts and filling in below them.

I agree with the better solutions, but it's a three car garage with the double layer of drywall, so taking the ceiling down is not going to happen. I've been in the house for 8 years, so to get the contractor back at all is a minor miracle:)

I guess the options are 1. As the contractor suggests, or 2. try to blow additional insulation above the existing insulation. Seems like the second would give better contact with the floor, and I'm wondering if either of these has worked for anyone.

GBR 01-04-2011 09:28 PM

The existing f.g. batts with the gap to the heating side are getting air drafts and degraded from the gap; Floor Insulation - Oikos

I would pay him extra for the extra insulation blown under the f.g. to compress it fully because the cellulose (hopefully) is a much better product than the builder's grade low density f.g.; “How To” Buy/choose Fiberglass Insulation. - DIY Chatroom - DIY Home Improvement Forum

I would seal the cavities under and above the knee walls with f.g. in garbage bags (fitting...) to block the air movement from the attic then house wrap the attic side of the knee walls to prevent wind washing. (In my "how to" article above). If existing is unfaced, paint some vapor barrier or oil based primer on the garage ceiling to stop any moisture from the warm wet vehicles degrading the insulation.


smitty202 01-13-2011 11:56 AM

Thanks for the advice Gary. The contractor was here last Friday and the fix seems to have worked. I live in southeastern PA, and we have had some below average temps for the past week. There is a significant improvement in the room and the gradient between that room and others is no longer noticeable.

BTW, I had previously filled gaps in the knee walls. I had also insulated the outside wall (the builder had insulated the knee wall) and used house wrap to stop the wind washing.

Seems we finally have this one solved.

All times are GMT -6. The time now is 09:47 PM.