I used an unusual Portland cement lime mix. Do I need to start the dome over?

Hi! I’ve just finished the dome, but unfortunately I’m just realizing that I used Portland cement with lime, and didn’t take the extra lime into account when making my mortar mixture. After reading here it looks like that won’t work. I’m going to need to redo the dome and take the firebricks down. Since they are already dry, are there any tricks to remove them and try and salvage them?

Hello Chelsey and welcome to the BrickWood forum.

Sorry to hear about the mortar mixup. While it’s important not to wait too long to take apart your barrel, it’s even more important to know whether in fact you’re going to need to do that.

It would help to know the exact ratio of cement to lime that was in the premixed bag. A photo of the bag itself would be ideal, as there should be a mix ratio table printed on it.

You might still need to remove your barrel and start this step over, but let’s make sure first.

I’m flagging this post so @BrickWood sees it, too.

Crossing my fingers for a good outcome here!

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Thank you so much for the response! It is Sakrete Portland Limestone Cement type 1L. I can’t seem to find where it has the ratios on the bag.

Hello and welcome to the forum. I’m a little confused by your post.

First, are you saying you added the specified amount of hydraulic lime to your mortar in addition to whatever may have been in the portland cement? Or that you forgot to add extra lime and only have whatever lime was in the portland cement. I’m guessing the first but want to confirm.

Second, I cannot find anything on the Sakrete website that says they make a portland cement with lime. I did find that Quikrete make a portland-lime cement that is 70% cement and 30% lime by weight…

As @bikerbudmatt says, a picture would clarify a lot.

Hope this helps.

Here is a photo

Correct I didn’t take into account the additional lime in the cement and added more

Thanks for the photo, Chelsey.

This seems a little extra-weird, because the closest thing to that name that Sakrete lists on their website is type “IL” (I for Indiana), and I couldn’t find a type “1L”. @kgondoly Ken is our mortar expert on these boards, and I know he’s done extensive research on the different types and mixes. The “IL” mix is an industrial mortar, and has some serious safety considerations attached.

Without knowing what’s in it, it’s hard to advise you. Who supplied the mortar to you? Can they give you more information on the ratio of the mix?

Interesting. I called up the help line a Sakrete. That’s a brand new product that they are switching to because its a “greener” product for them to manufacture. It’s not on their website yet but they are going to email me a data sheet which I’ll post when I get it. They indicated that you can use it like normal portland cement though.

Here’s an interesting article (if you’re a nerd like me) on Greener Cement.

Kudos to Sakrete for having a real, live person pick up the phone on the first ring…

p.s. @bikerbudmatt is too kind. I’m no expert-just like nerding out on my hobbies.


Thank you sooo much for this help! You all are so great.


This is a tough call!

My two cents… at this point, continue building the oven. It is going to be nearly impossible to remove the mortar from all of those firebrick (making them clean enough to reuse) and then scraping mortar off the oven hearth - and don’t forget the mortar that has adhered to the foam form.

If it were me, I would continue building the oven as shown in the instructions and slowly cure the oven - but keep an eye on the mortar as it cures over several days. If the mortar has an issue, it will flake out a bit - and those sections that do “flake-out” can be cleaned with a wire brush and filled with a high-temp mortar from Rutland or DAP ($10 a tube).

If you were going to use the oven on a patio of a resturant… this would be different. But for general home use, I’m willing to wager that you won’t see any issues in the mortar.

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OK. Here’s another link I found about Mortar Strength.

It looks like what you inadvertently did was create a mortar somewhere between a Type N (1 part portland and 1 part lime) and a Type O (1 part portland and 2 parts lime). The good news is that, in general, Type O mortar still has about 70% of the strength as the type N. Given the size of the pizza oven I think you’ll be OK but, for sure, proceed as @BrickWood suggests.

The one thing I noticed is that the more lime there is the longer it takes the mortar to set up so you may want to give it a few more days drying time before the curing fires.


I call 'em like I see 'em, Ken. And I think your further response proves it. I’d be very okay with ~85% strength. Hope you’ll keep nerding here for a long time!

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That is fantastic news!! I will take 85% as well :slight_smile:

Again, I very much appreciate all the help. What a fantastic community!