Wet Mortar vs Dry Solution for Oven Floor

[Vivi88]

Hello!

My original plan was to mortar the bricks down onto my insulation floor using a 3:1:1:1 mixture of cement, fireclay, sand and lime. However, I'm hearing more of potentially using a 1:1 dry fireclay and sand mixture.

What are the pros and cons of each for the floor?

My dome will sit on top of the firebricks, so I'm worried over time the weight of the dome will push down the outer bricks but leave the bricks in the middle, which would result in a inconsistent / not level floor. Is this an issue?

I'd imagine setting the bricks on a dry mixture would be easier to level on the floor, but I'm just worried about the long term effectiveness of this method.

[UtahBeehiver]

You do NOT want to mortar floor bricks, you need the bricks to be able to expand and contract, as well as you do not want t mortar the first dome course to the floor for the same reason. The only reason you would see settling of the floor is if the floor insulation does not have enough compression strength, hence you need the floor insulation to have at least 70 PSI at 5% compression.

[Vivi88]

How would I be able to check out the compression strength? I used a 5:1 perlite cement ratio.

[Vivi88]

You do NOT want to mortar floor bricks, you need the bricks to be able to expand and contract, as well as you do not want t mortar the first dome course to the floor for the same reason. The only reason you would see settling of the floor is if the floor insulation does not have enough compression strength, hence you need the floor insulation to have at least 70 PSI at 5% compression.

Also is there any preferred type of sand to use in the 1:1 fireclay sand dry mixture. Any tips I should know if using this method to lay the bricks on the insulative floor?

[UtahBeehiver]

You originally did not say you used 5 to 1 pcrete. This ratio is fine for using under fire bricks since the pcrete ratio exceeds 70 PSI. we have published a pcrete chart numerous times on the forum.. If you look at the FB pompeii plans they suggest a peanut butter consistency of regular old sand and fire clay installed with a notch trowel.