Fire box material

[flyingarmstrong]

I just installed a used Century Heating 2500x insert. I thought my fireplace was masonry, however if I pound on the brick inside the firebox it does sound like it isn't solid brick behind it.
I cut the old damper handle guide right before it attaches to the damper in order to get my liner to fit. In the process I gut into this brick material. Is this an asbestos material? It's a 1978 house, exterior brick fireplace.

Thanks

 

[redyute]

I just installed a used Century Heating 2500x insert. I thought my fireplace was masonry, however if I pound on the brick inside the firebox it does sound like it isn't solid brick behind it.
I cut the old damper handle guide right before it attaches to the damper in order to get my liner to fit. In the process I gut into this brick material. Is this an asbestos material? It's a 1978 house, exterior brick fireplace.

Thanks

Its not solid brick inside the fire box, the bricks appears to be of some kind of clay or something lol, when I did mine a few months ago I noticed that, but I'm sure the guys on here can add to my little bit of information lol

 

[begreen]

The fireback may be built out of firebrick. It's usually a tan color. There could be a layer of insulation behind the firebrick or an air gap before the outer masonry.

 

[flyingarmstrong]

The fireback may be built out of firebrick. It's usually a tan color. There could be a layer of insulation behind the firebrick or an air gap before the outer masonry.

Was asbestos common?

 

[begreen]

Not as an insulator to my knowledge, but it was used in some mortars during the 60s and into the 70s.
https://www.mesothelioma.com/asbestos-exposure/products/mortar/

 

[flyingarmstrong]

Not as an insulator to my knowledge, but it was used in some mortars during the 60s and into the 70s.
https://www.mesothelioma.com/asbestos-exposure/products/mortar/

I would think it would be out by then. Looking at it, it seemed really light and fibrous, although I know you really can't tell by looking at something.

 

[begreen]

It's hard to know what the mason used. I would treat anything unknown like that with the assumption that it could be asbestos. While working in that area wear a respirator mask and wet down the area with a water spray bottle first. Bag the material in a plastic bag for disposal.