What to put under the floor bricks?

[di11on]

Hi folks,

What is the best material to put under the floor and should it be wet or dry?

I understand the FB instructions say a 1:1 fireclay sand mix. The Panyol instructions say to use grog and/or "very dry sand".

I don't have fireclay, but have grog and was thinking of a 1:1 grog sand mix. Would this be ok?

The Panyol instructions say "very dry sand" is this important? I've red of people using pastes and wet sand....

I'm thinking dry would be good because there are no issues with drying it out later... but some moisture is good for placing and levelling?

Thoughts?

[david s]

Re: What to put under the floor bricks?

If placed wet it will harden into a solid. If placed dry it can move. The problem is removal of the water. The better solution is calsil board, which is both dry and a superior insulator. Its downside is that it is way more expensive than vermiculite, perlite or either of them mixed with cement to form a lightweight concrete.

[di11on]

Re: What to put under the floor bricks?

I have a layer of Vermicrete already poured (10cm thick). It's now been in the sun for a good 10 days so is nice and dry.

I'm wondering what to put between the vermicrete and my floor bricks and dome (the dome will surround the floor bricks).

[stonecutter]

Re: What to put under the floor bricks?

Just do it with damp sand and omit the grog...it will make it a pain to screed with all the bigger particles in it.

[di11on]

Re: What to put under the floor bricks?

Thanks,

I presume the sand should be of fine granularity?

I have fine grog: 0 - 0.5mm and "coarse" grog 0-1.5mm - is there some benefit to using either of these?

Thanks again

[stonecutter]

Re: What to put under the floor bricks?

The screed should only be a quarter inch or less, if your insulation slab is anywhere near level. It doesn't really matter what is used as long as it doesn't burn up or breakdown from the heat.

[wotavidone]

Re: What to put under the floor bricks?

It's just there to take out any irregularities so you can get your floor nice and level. As long as the material is fine enough to screed, coarse enough to not disappear into the gaps in your vermicrete, and doesn't breakdown when heated.