Concrete Slab Design

[poolballboy]

Hi, Thank you in advance for your support with my question.

I am doing a Barn conversion (Old piggery) and I need to remove the middle strip of concrete in the barn and replace it with something a little more up to spec.

The Barn is 22m x 12m and the middle 8m x 22m section is raised 100mm above the two edge concrete strips used as walk ways. The two edge strips are reinforced concrete that the metal structure sits on, however, the raised middle section looks like rice crisps with a screed over the top of it. Underneath the rice crisp type concrete is a DPM and what looks like 100mm of compacted ballast (Sand and stone). Underneath the Ballast is a solid clay base.

First questions is - what is this Rice Crispy cement mixture?

Second question is - What slab design will I need to bring the middle concrete section up inline with the two existing concrete edges? I will be insulating above the concrete (100mm insulation) and finishing off with a 65mm screed for the underfloor heating.

Thanks

Andy

 

[noseall]

Hi, Thank you in advance for your support with my question.

I am doing a Barn conversion (Old piggery) and I need to remove the middle strip of concrete in the barn and replace it with something a little more up to spec.

The Barn is 22m x 12m and the middle 8m x 22m section is raised 100mm above the two edge concrete strips used as walk ways. The two edge strips are reinforced concrete that the metal structure sits on, however, the raised middle section looks like rice crisps with a screed over the top of it. Underneath the rice crisp type concrete is a DPM and what looks like 100mm of compacted ballast (Sand and stone). Underneath the Ballast is a solid clay base.

First questions is - what is this Rice Crispy cement mixture?

Second question is - What slab design will I need to bring the middle concrete section up inline with the two existing concrete edges? I will be insulating above the concrete (100mm insulation) and finishing off with a 65mm screed for the underfloor heating.

Thanks

Andy

Whilst your rice crispy description is as bewildering as it is intriguing - It's a pity they haven't invented a device that allows us to take pictures any time any place and be able to upload onto a forum...

 

[poolballboy]

You are right, I should have taken my phone with me and got some pictures. Imagine not carrying it about with me 24/7 like a zombie. Here we go, pictures if the rice crispy cement.

 

[freddiemercurystwin]

 

[gonch69]

That looks like what they call no-fines concrete

 

[jks7492]

Its concrete, just without the fine aggregate that you normally have in the mix.

How thick is the existing slab and screed that you're taking out?
You'll need minimum 100mm concrete for your new slab, so by the time you've excavated the 100mm level difference and then another 100-150mm for your slab depth you might already have taken out all of the sub-base that's there?