Vermiculite in concrete slab?

[Moley]

Hi People,
I have bricked up to the right height for my pizza oven base. I am pouring a concrete slab 150mm thick with 2 layers of reinforcement mesh. I am am going to mix 1 part concrete, 1 part lime to 5 parts gravel. Question: Should I add vermiculite to the mix to help insulate the slab. I am going to put two layers of clay pavers on the slab for the oven floor. Is the vermiculite in the slab useful or not?
Thanks

[splatgirl]

Re: Vermiculite in concrete slab?

Hi Moley
The support slab should be standard reinforced concrete. That is your structural component. As a separate layer on top of that and under your oven floor you need an insulation layer of vermiculite/concrete or insulation board.

Review and/or download the Pompeii oven building instructions from this website.

Good luck with your build!

[david s]

Re: Vermiculite in concrete slab?

Adding vermiculite to a concrete mix will reduce its strength. Like Splatgirl says follow the plans.

[Neil2]

Re: Vermiculite in concrete slab?

"1 part concrete, 1 part lime to 5 parts gravel."

Skip the lime. The "gravel" should be well graded concrete aggregate.

Also, use rebar instead of (or in addition to) the WWF. Something like 1/2 inch on an 8 inch grid both ways (or 3/8 inch on 6 inches both ways). WWF (welded wire fabric) also known as reinforcing mesh, is primarily used for crack control in thin slabs.

Embed all the ends either down or sideways about 12 inches. Also 4 inches (100mm) is plenty thick enough, 6 inches (150 mm) is not necessary.

[Moley]

Re: Vermiculite in concrete slab?

Thanks people you have been a great help and yes Ive now downloaded the plans.

[eatingmorefood]

Re: Vermiculite in concrete slab?

Splatgirl David & Neil2,
pouring my slab this weekend.
thanks for the above tips !
EatingMoreFood

Attempting to build my oven with 80% recycled and leftover construction materials !

[Lburou]

Re: Vermiculite in concrete slab?

Splatgirl David & Neil2,
pouring my slab this weekend.
thanks for the above tips !
EatingMoreFood

Attempting to build my oven with 80% recycled and leftover construction materials !

How did it go?

[eatingmorefood]

Re: Vermiculite in concrete slab?

Hi !
Oven build is going great !
We are in the thick of winter, so it will continue t ogrow when the grass greens up. Pictures are here : making pizza wood oven pics are half way down the page. Strap was a big plus. All recycled builders materials so far, exception was second blocks and concrete (100 bucks total).
thanks for your inspiration!
EatingMoreFood

[Lburou]

Re: Vermiculite in concrete slab?

Hi !
Oven build is going great !
We are in the thick of winter, so it will continue t ogrow when the grass greens up. Pictures are here : making pizza wood oven pics are half way down the page. Strap was a big plus. All recycled builders materials so far, exception was second blocks and concrete (100 bucks total).
thanks for your inspiration!
EatingMoreFood

Awesome goal, and good progress toward it!

Good luck