Should I Remove High-Temp Mortar I Accidentally Used as First Stucco Layer?

I used Sakrete high heat mortar (I had left over) for 1st coat stucco over insulation blanket. I should have checked here 1st. Question -should I remove this layer and used regular mortar/stucco or can I stucco over this ? Sacrete says that high heat will cure after 30 days . Any thoughts befor…

Hi Erminio,

In this case, I would say remove it. While it will not do major harm to your oven, it also will never cure completely, and so there will be a floating layer under your finish stucco coat that will defeat the purpose of the chicken wire matrix.

The good news (and there is good news) is that you should be able to pull up the chicken wire and remove almost all the high-temp mortar without much of a hassle. If you do it carefully, you can get the big chunks of mortar out of the chicken wire, replace it and fasten it over the mineral fiber, and work with the much less expensive regular mortar. Sakrete Type “S” will do the job, and it is about a tenth the cost of the high-temp mortar. When it dries, it will form a hard, protective shell over your oven.

Don’t worry about getting every last bit of the high-temp mortar out of your chicken wire or off your insulation. Just focus on the big sheets and chunks. When you lay a complete layer of regular mortar or stucco mix over this, that layer will draw out any remaining moisture from the little bits of high-temp. (And in case the thought comes up, that’s only because they are crumbs or smears. It wouldn’t work out for high-temp that has been applied as a complete structural layer as you have now.)

Glad you asked, and good luck moving forward!

1 Like

Thanks for the advice !
I should have checked 1st but better late then never!!

Here’s where I am so far.:blush:it been a blast


Good looking oven you’ve got there! Thanks for the photo!

1 Like

@bikerbudmatt is 100% spot-on! That HTM will not fully cure until it reaches those crazy high temps that only fire can produce (in a wood-fired oven). If it was used on the outside of the oven, it would feel hard… but it would never fully cure. Then your stucco shell is bonded to a material that will eventually flake off.

BTW - Excellent Forum Title! You mostly likely prevented a number of people from doing the same mistake if they search / see your post in advance.

I will add this to BWO Instructions 2.0!