Crumbling mortar

Well, it’s spring and it seems our Minnesota winter may have taken a toll on the high temp mortar in our oven. We fired for the first time in 2021 and used it frequently spring, winter and fall in 2021 and 2022. This spring, we noticed mortar crumbling from between the firebrick inside the oven (a little) and on the outside edge (a lot).


  1. What do we need to do to correct the problem or prevent further damage?
  2. Do we need to take action before using the oven again?


Eric & Marilee

I’ve been hearing from Minnesota folks over the past couple of weeks … you folks had the share of winter we did not receive in Connecticut this year.

Yes, that warrants fixing. We recommend a product like this:

Like the high temp mortar, this product fire-cures and then withstands temperatures up to 2,000 degrees F. You can use any similar fireplace mortar product as long as it is non water soluble.

Brush out the area with your masons brush. Use a caulking gun to work it in and a putty knife to smooth it out. Let it rest for a day, then do a series of curing fires to heat set it. You can compress the schedule from your initial curing, but your repairs have to be heat set.

I don’t see clear photos of the oven outside, so can’t speak to it. Feel free to share more photos and describe what’s going on there.

Sorry your oven is indisposed, but it has many more years ahead of it!

Thanks! Amazon has our order and we’ll go to work on it later next week after it warms up again (snow again tomorrow).

The inside of the oven has some chipping mortar but not nearly as bad as the front.

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