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insulating 1 1/2" airspace load-bearing masonry walls

Our house was built in 1957. It is a brick, 1 story, low-pitch roof house w/ a crawl space located in Salt Lake City, Ut. We are working on insulating it. Today we began to drill holes in the sheet rock in order to blow insulation into the walls, which currently have zero insulation. However, once we started drilling holes, it became apparent that there is only 1 1/2" of air space between the interior sheet rock and exterior brick. What is the best way to insulate this narrow space? We were planning to blow fiber-glass insulation into the cavity at 1.5 lb/ ft^3, but we are at a loss of what to do now. Please help!
Note: The masonry walls are load-bearing, with sheet rock attached to furring strips.

Timothy Miller
Re: insulating 1 1/2" airspace load-bearing masonry walls

You may want to create a double wall system installing a new interior wall 2 inches away from the existing an insulate this cavity instead. I.5" of fiberglass is darn near no use at all.

Re: insulating 1 1/2" airspace load-bearing masonry walls

You could fill the void with closed cell spray foam. That will give you about double the R-value per inch than fiberglass.

Another variation of what the above poster mentioned is to Put rigid foam over the exiting wall to your desired thickness and then drywall over that. You will loose less space than erecting an entirely new stud wall.

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