Can I use the pre-mixed High-Temp mortar (like HeatStop) that is sold in bags (or in a pail) when building the Barile series oven?

Yes, but there are two MAJOR factors to consider before using factory made premixed high-temperature mortar for our Mattone Barile series ovens.

First, you need to consider the cost of the high-temp mortar per bag. Since the joints on the firebrick ovens are larger than a typical 1/8" joint, you will be using (7) bags of mortar for the Mattone Barile Grande and (6) bags of mortar on the smaller Mattone Barile. Those bags of mortar can quickly add about $200 (or more) to your oven project.

Our low-cost high-temperature mortar recipe is very inexpensive, works extremely well and is used all over the planet!

Second, if you do decide to go with premixed mortar, you MUST MAKE SURE that it can be used outdoors. Many high-temp mortars are designed for indoor fireplaces and ARE NOT designed for outdoor ovens. Look for the phrase “NON-WATER SOLUBLE” on the bag of dry mortar.


Hello @BrickWood while I would love to use the custom high temp mortar recipe your suggest, I can not find all the acceptable ingredients in Montana. I did find HeatStop II and HeatStop 50 (both dry mixes).

Questions: can I use either product for the high temp mortar? Inwant to confirm how much dry mortar do I need for the Mattone Barile firebricks and putter regular bricks (instructions say 400lbs on pg 3)?

Thank you very much! Spencer

Hey there!

We’ve vetted HeatStop 50 in the past, and yes, it is an excellent dry premix high temp mortar. The “50” appears to refer to the bag size!

As for how much material: some of that depends on your bricklaying style. @BrickWood lists 400 pounds in the materials list, but there are two factors involved in that quantity:

  1. It includes an industry-standard 10 percent allowance for waste and re-do. (You might need that, so don’t write that off.)
  2. BWO also presumes that a novice bricklayer is doing the work. Any of us on our first outings with a project like this find that we waste more than the allowance because of things like “I mixed too much and I didn’t expect it to dry that quickly…” (That might be you, but I don’t know that!)
  3. A related factor is what happens when you’ve laid every course but the final one, and you run out of high-temp mortar because you didn’t have enough on hand.

If you prefer, you can calculate your need by looking at the yield of the mix rather than the dry quantity. According to the manufacturer a 50 pound dry bag will yield 60 pounds of mortar when mixed. That’s about 6½ bags which you’d round up to 7 bags for a 400 pound total requirement.

You’ll end up saving a bag of mortar if you calculate that way.

If you have a supplier close by, in my opinion you could safely do this.

How’s the build coming in general? Hope you’re enjoying the work, and if you have photos, would love to see a couple!

1 Like

Thank you for your quick reply, Matt.

You’ve answered all my questions, and I really appreciate the help thinking about dry ingredient versus the wet yield. I will work with my local company to see if I can order in the larger bags. Otherwise I will place an order on the Internet.

I will post the photos on a separate post soon.

1 Like