Mortar froze while curing during a cold freeze

So, I laid the barrel of the oven the other day while the temperature was in the 40s and I wasn’t paying attention to the weather and it dropped to the 20s overnight and i didnt cover it or anything. When I came out in the morning everything was covered in frost and there were icicles dripping from some of the joints that were frozen solid. Now the mortar feels crumbly after almost 2 days of drying and some of it feels soft and the parts that chip away I can crumble with my fingers. Will the curing fires make the mortar set enough where it won’t matter? Should I break the barrel apart and lay the brick again in warmer weather? (I sure hope not) if it’s necessary though I will do that and wait for sunnier days

Not what we wanted to hear on this Holiday weekend! Can you attach several photos so we can see exactly what the mortar situation looks like? I’m not going to say you should fire the oven w/out getting a good look at that mortar (from all angles - inside and out), but this might be a situation where you fire the oven before you finish the oven… but again - we need to see those mortar joints first.

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Oh no!

Just adding on to @BrickWood ’s request, please give us a closeup of one of the joints that you said was “crumbly.” My experience with the high heat mortar is that it completes its initial set within an hour, so I am very interested to see what this looked like after setting overnight. The icicles in particular seem odd.

Let’s figure it out.

It does feel harder and less crumbly today. But I am still worried because it still seems a bit softer than the mortar between the red bricks which is the same high temp blend

From what I see, I am recommending that you DO NOT tear down the oven. This oven looks better than many oven pics I have seen over the years!

I suggest you purchase an inexpensive tarp that will cover the entire oven AND the exterior red brick. Then place a small space heater (not the big dish kind, but a small bathroom heater) inside the middle of the oven and turn the heater on for 3 or 4 days.

Normally, I wouldn’t recommend curing the oven before finishing the oven, but in this instance, let’s go ahead and cure that oven (even before adding the chimney brick). After you have completed the 6-day pizza oven curing cycle, take a good look at those mortar joints in question and let us know what you see (plz include pics &/or video).

I’m betting my wife’s entire paycheck that you will be a-okay!

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Van,

In my opinion that’s pretty much how those joints are supposed to look. I completely concur with @BrickWood on this. The reason we’re both saying to dry it out and then follow the curing cycle now instead of waiting until after your insulation is in place is simple: the high heat mortar does not fully cure until it is fired. You want to do it according to the “book” — low and slow, and building up so that you drive out the rest of the moisture in the first 3 fires and then fire-cure the mortar in the last 3 fires.

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Okay great! Should I lay the back of the oven before doing this? I feel like it would need it to keep the fire contained.

Yes. I didn’t pick up from your earlier messages (though you said it!) that you have just the barrel laid right now. Yes, do the back, then place the heater in for three days as @BrickWood recommended. You want the mortar to feel “set” to the touch before you go ahead and fire.

The order for your oven will be: build back, low heat for three days or until mortar dries to touch, then follow the initial curing directions scrupulously. **Be very careful ** not to push the curing sequence, even though the first couple of fires will make you wonder whether you accomplished anything.

What we’re trying to do here is get the mortar to its final set form without cracking it.

Once you’ve got curing fires done, you won’t have to worry about the cold weather again. Winter conditions suggest you will want to tarp the oven after this and pick it up in the spring rather than trying to install insulation and stucco, but you know your local conditions better than I do.

Keep us posted…especially now that @brickwood has a wager riding on this!