Quikrete for Hearth Slab

[sollila]

I poured my hearth slab at 5" using quikrete which I now know isn't a good insulator. I was going to lay fire brick horizontally to build the floor, so the floor depth would only be 4.5" which doesn't sound like enough in my reading.

Since I haven't started the floor and dome, I'm thinking I could lay two layers of fire brick, and do the bottom layer horizontally so I would add another 2.5" for a total depth of 7" of fire brick on the over floor. Does that seem sufficient?

Thanks!

[DavidApp]

Re: Quikrete for Hearth Slab

Hello Sollila

I don't see any mention of insulation between the hearth slab and the brick oven floor.

You must have some type of insulation. Either Ceramic fiber board or Insulating concrete made up of Portland cement and Perlite or vermiculite.

I built an oven as you are describing without the insulating layer. It takes a very long time for the floor to heat up and does not stay hot for long.

Check for threads on hearth insulation for more information.

[jeeppiper]

Re: Quikrete for Hearth Slab

Not sure, but it seems you are missing the point that DavidAPP is making.

You already have your concrete slab, next you need a layer of insulation (either ceramic fiberboard, or insulating concrete (perlite mix with concrete). I suggest getting some 2" fiberboard and lay it down.

Then, on top of insulation, you lay your hearth firebricks. The firebricks are your thermal mass that stores the heat. The insulation layer prevents that heat from escaping.

[GianniFocaccia]

Re: Quikrete for Hearth Slab

I poured my hearth slab at 5" using quikrete which I now know isn't a good insulator. I was going to lay fire brick horizontally to build the floor, so the floor depth would only be 4.5" which doesn't sound like enough in my reading

Not sure what you were reading, but the best next move is to download the free FB Pompeii Oven plans and read through them. You will find that 2.5" is the standard floor depth for pizza ovens.

If you draw up your oven plans and work out details before you continue building, you will save yourself a ton of time and aggravation, and the need to remedy what didn't work out.

[sollila]

Re: Quikrete for Hearth Slab

Thanks everyone. It seems like the insulation is needed. I was hoping to circumvent that by adding more firebrick, that that theory seems incorrect.

Other than ordering online, what type of suppliers typically carry fiberboard? Brickyards?