What is this in my smoke chamber?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Feb 20, 2022
My wife and I recently purchased a house with a fireplace. I noticed that in the smoke chamber there is a side that has some strange white protrusions in it.

I touched them with the fire poker and they are hard as brick. Is this some kind of parging that was done to fill in some gaps? Or what?

I do have someone coming out to do a level 2 inspection this week.