Cracks on mortar shell: repair or ignore?

Just finished up the second layer of mortar on outside of insulation. Perhaps did it at the wrong time because it was around 80 degrees and sun. As soon as mortar started to dry some cracking took place (the first layer did not crack as it was on cooler day with not any sun). The plan is to paint over the mortar for now, and then in August build a roof & “house” over the top and sides of oven. If I put paint over the mortar for now and a roof coming soon, is it important to fix these cracks? I live in Oregon and it will rain in the summer. I could also just leave a tarp over it until the roof goes on. (I’m just really tired of mixing mortar now unless absolutely necessary…but also don’t want to leave a problem for later).

If you are satisfied with the overall finish of the stucco (smooth contour and dried hard), then there’s no need to mix more mortar. But you should fix it to keep a sound surface underneath your paint layer and eventual superstructure.

Fortunately there’s an inexpensive product that I found easy to apply.

This applies with a putty or taping knife, straight from the container. It is textured to match your stucco, and I found that all I really needed was a little finesse and finishing work with the putty knife itself.

When I checked this morning it’s about $10 for a 32-ounce container at

According to the tech data sheet, it’s ready to paint after a 3 day cure.

Hope this helps and let us know how it turns out!

I did not use stucco (couldn’t find where I live) instead used mortar. Will this still work or should I use a ready made concrete type patch like this

Yes, absolutely. I used standard “Type S” mortar for my stucco shell. An actual stucco mix is mortar with some kind of reinforcing fiber added. You didn’t and don’t need it for this application.

I don’t recommend the concrete patch in particular; mortar is a weaker mix of the ingredients that go into concrete and I’d stick with a product recommended for mortar/stucco.

Presuming that you wet-sponged the mortar after applying the second coat, your stucco shell should have a grainy surface. This repair mix will blend very well with that. And again, you won’t see it under the superstructure you plan to build, but it’s important that you have an integral surface.

Looking forward to seeing your results!