I have a gas fireplace that bumps out from the side of the house. It is always been drafty and super cold in the winter, today I went down and pulled down the one piece of batt insulation that was there and there's about two foot Gap behind it, this was also the fact with the two rafters next to it, as well as a hole in the floor underneath the fire place and a hole in the side of the house where you can see siding. I assume there used to be a external vent for the different fireplace. So I did proceed to fill the void with fiberglass batt insulation and the two holes along with finishing all the rafters that whole side of my house which was missing some. Was it bad for me to have fiberglass insulation in this void under my fireplace?

  • Hello, and welcome to Home Improvement. Would you add a picture or diagram of your setup, so that we can better understand what's up? Jan 30, 2019 at 12:17

1 Answer 1


These areas have always been notorious for being under insulated. Filling the areas with fiberglass should be fine. We spray foam the entire area under fireplace bump outs. This keeps the drafts and cold weather out.

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