Trouble finding high temp mortar mix "ingredients"

Hi there,

We have just finished our base and put the hearth slab on top! Now on to the Oven!

I am having trouble locating the correct parts for my high temp mortar. We are in Rochester, NY. Portland cement is easy to find but struggling to locate the remaining materials. Any idea on what types of stores we should be calling? Also, should we be using high temp mortar for the outside frame? or can we use regular old mortar for that part? The instructions are a bit un clear on this piece.

Thank you!

Hello, and welcome to the BrickWood forum.

We heard recently from another builder in Buffalo that they were having the same problem. I’m wondering if there is a local shortage of fireclay in upstate New York.

You would look for fireclay in ceramic supply outlets, and lime in garden supply stores or pool supply stores. The fireclay comes graded by “screen size,” and you want a relatively coarse screen—anywhere between 10 and 25. Screen grades get up into the hundreds, but those are for fine porcelain glazes, not mortar.

Ideally you should use high temp mortar for your outside frame. If you locate the other ingredients, you will have plenty to do that. Regular mortar is acceptable for the frame, but you have hot firebrick in contact with the standard brick, so there is a chance it will eventually deteriorate.

Hey. Im the guy from Buffalo! I could not reply to the last post as it said it had been deleted? Anyway thanks for your reply. You are the MVP of this forum and gave me the confidence to do this. So seriously thanks a ton it has been such a fun project so far. Been doing with my dad and loving it. Doing the herringbone now!

I found everything in the area. Clay even closer to you.
Fire Clay at Studio Sales Pottery Avon NY
Hydrated Lime ( You can find in Rochester I bet) I got at Buffalo Cement Accessories
Silica Sand Get at any pool supply store. Ask for filter sand.


Thanks Jack! I will give them a call tomorrow. This forum is great. Good luck with the oven floor!

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So glad you posted with an update and you were able to find everything. Don’t know what happened to your earlier post, but I do know you’ve made Mr. Haring a happy builder.

The herringbone was one of my favorite parts. Like laying a parquet floor or solving a puzzle. Really happy you and your Dad are enjoying this project.

I’m hoping @BrickWood will add the stores you mentioned to the materials finder. A big THANK YOU for persisting and tracking the materials down.

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Hi Matt - I am still having trouble locating my fire clay, and I am ready to get moving with my oven. most local pottery supply stores have said it is backordered 1 month +. I am now looking into just spending the money to buy high temp mortar. I know I am looking for non water soluble and high heat resistance, is there a specific number of degrees I should be looking for? Does anybody have experience using Firerock mortar?

I’m so sorry to hear that! I just came back from a camping trip and family visit in the North Country, and my daughter was telling me they were putting off projects for a year or so for the same reason. I know you don’t want to do that with your oven project.

I am looking again at the masonry supply store locator, and it looks like most of the masonry supply dealers in your area are marketing complete kits. In my own build, I used Harbison-Walker’s “KS4” mortar, which meets all the specs and sells for about $55 for a 55 lb bag. (It may have gone up in the past few months, but the last purchase I made was last summer.) I needed 9 bags to complete my oven, but it was totally worth it for the convenience.

FireRock looks pretty pricey, and you’d use roughly the same amounts as I did. It appears to come in 25 pound bags, priced at an eye-popping $204 a bag in one online outlet (and that was a “sale” price!)—but I also saw an outlet in Georgia that would sell it for $40 a bag out the door. A product specialist at one outlet admitted that it was “similar” to heat resistant mortar but was designed for FireRock products only.

My suggestion would be to bite the bullet and call the HWI outlet in Cheektowaga. If you own or have access to a pickup truck they will palletize your order and load it for you. Company-wide, they are supposed to be aware of BrickWood specs and should be recommending this or a similar product—but you can save the trouble by just asking for “KS4” and explaining it is for a BrickWood pizza oven.

Hope this all helps, and please let me know how it works out for you.

If you happen to want to swing by south-east Michigan I have a bag and a half of fire clay and a bag of hydrated lime left over from my project that I honestly don’t know what to do with. I guess I overbought…

That’s very generous, Ken! I’ll leave it to him to decide whether a road trip from mid-state New York would work. We drove it while we were camping a couple of summers ago and it might take a while. :slight_smile:

If you are completely done with those materials, they’re the sort of thing you can put on Craig’s List, or share them with a “freecycle” group if you don’t need money for them. They’re going to be valuable to somebody local to you, especially in this addled supply-chain summer.

I got Mine from I bought two bags for $113 with shipping total Honestly I only needed one but I was very careful not too waste much mortar.

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Did you end up finding it… I will give you the rest of what I have for fire clay it should be enough to get you there I did not use half of what I got. I am in Buffalo. Let me know if you are still in need!

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On the west coast, I found fire clay at Home Depot. Not all stores, so call store before you go.

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