Oven Floor and Insulation question...

[Dooozie]

Hi all,

So, I'm just starting my 900mm build. The insulation (50mm board) and bricks are cut ready for the floor and I've cut approx 50 bricks in half so-far for the dome, we're still having frosty mornings here so I haven't started sticking it all together yet.

I haven't seen anything definitive about fixing the floor. Should anything go under the insulation or does it just sit there ? And what goes between the insulation and the bricks ? Sand or a fire cement mortar. I need something to level them up as some of my bricks vary by maybe 2mm.

If it makes a difference, I'm building my dome on top of the floor.

Thanks..

[david s]

The floor bricks are best laid loose so they can freely expand individually. This also makes the replacement of any far easier. So to level them a dry mix is better. A1/4” deep mix of 50/50 sand and powdered clay applied with a notched trowel does the trick of levelling uneven floor bricks.

[Dooozie]

Ah, thanks for that..
So, (this may be a really stupid question) what about the first course if dome bricks? Will they be bonded to the floor or just placed in position so the floor can expand beneath them?

[david s]

No, that’s a very good question. Most builders favour not bonding them to to floor bricks., althoughwith all that weight sitting on those under the dome I can’t see that they’d move much.

[Dooozie]

Great stuff, thanks.

I must admit, I have been wondering about all that weight sat on the outer edge of the insulation board. If I didn't know it has been done many times before I wouldn't believe it could take the strain.