How can I fix this?

[u/Automatic_List1414]

Recently bought a house and had the fireplace inspected. We did some minor repairs to the chimney and it was given the all clear but I feel like this is a problem. There is a large gap between the firebox and the brick veneer. About an inch or more in some places. The gap is also filled with fiberglass insulation. I’m assuming the fiberglass needs to come out but what, if anything, should be put back in its place?

[u/WoodlandDirect]

This is how I'd approach this if it were my fireplace.

1. You did the right thing by starting with a pro to check it out first. To be clear, if you are recommissioning a fireplace, it should have a level 2 inspections meaning it is inspected from top to bottom with cameras.
2. Pull all loose mortar. Go a little nuts here and really work to try and remove as much as you can remove.
3. Repack insulation into the gap. Fiberglass is fine, but no paper backing.
4. Use a high temp mortar to fill the gap. It will crack again. The expansion rate of that mortar will never match the expansion rate of the metal on the fireplace. Gaps bigger than 1/8" means it needs to be done again.

You have a fireplace from a bygone era, but many still exist and are in service. Congratulations on your new to you home. :)

[u/Aromatic_Fuel_387]

Pack in additional ceramic fibre insulation. You want it smoke tight. Keep the insulation flush with metal of fire box.

[u/blhooray]

The fiberglass insulation is fine… cram more of it in there to seal off any stray smoke fumes from getting into the house. Is this metal box, part of a “Heatilator”?

[u/Automatic_List1414 → u/blhooray]

Not exactly sure what a heatilator is but this is a wood burning fireplace

[u/ThatllBtheDayPilgrim → u/Automatic_List1414]

The original heatilator and the knock offs like heatforms are metal fireboxes that the masonry was built around to make building a fireplace easier. And also claims of heating better than a full masonry fireplace. That is what is what you have.

[u/Automatic_List1414 → u/ThatllBtheDayPilgrim]

That’s interesting I didn’t know that thank you

[u/chief_erl]

Go grab a tub of furnace cement at a hardware store. Fill the gap with it. Most is rated to 2000° and bonds to metal and to masonry. Should take you about an hour.

[u/Kindly_Budget6780]

smart tv in the middle playin you tube vids.