The design depends on what you intend to put on top of it, so nobody can tell you the components until you tell us the design of the superstructure. There are various competing suppliers of the basic concept, so you also need to make up your mind whether you want to buy a system or invent your own.

Basically, you need some polystyrene and some concrete and some reinforcement, and probably a DPM and maybe a radon barrier. Oh and some hardcore and some blinding.

You don't need preformed stuff, just flat sheets. That sounds like a proprietary system.

How high will finished floor level be above ground level?

Yeah, well, that's why he got blank looks.

You could contact VikingHouse - they seem open to supply of materials/design/whatever with a DIY or local builder putting it together. Obviously they're mostly in Ireland but do do projects in the UK but it's not worth their while travelling to obscure corners for single builds. At least that's my impression from a little email exchange I had with Seamus when wondering about switching to a slab.

Ah, I didn't realise it was a specific system. I was just thinking 300 mm of EPS will give you a super insulated slab. Which is what we retrofitted our house with, except that our load-bearing walls are cold bridges.

In any case there is a way. You use a build-up of ground-bearing slab, insulation then additional slab on top. Floor insulation extends out past top slab to link up with external wall insulation.

Bit like this, except that the bottom slab would be ground-bearing:
https://www.dropbox.com/s/dwm0tjj60dcfnm1/detail.pdf?dl=1

Yeah I wasn't suggesting this detail, just that there is a way in certain circumstances. Using this technique saved us from having to dig 2.5 m deep trench foundations (the upper slab was contained with bog standard ply boxing).

Don't think the parts come in components as such, think you need to cut them from the large EPS cubes.

Have a look on Seamus's site below at the assembly and cutting patterns downlaods at the bottom.

http://www.viking-house.ie/passive-house-foundations.html

You could contact Airpacks who I think is where Viking gets his stuff, there is a link at the top of the webpage to an engineers report and it has the details of Airpacks

Posted By: Chris P BaconEven the "budget" DIY sheds sell it here in Sweden

I can't find anyone who sells the pre-formed edge profiles in the Uk, even though they are clearly on sale in big DIY stores across Europe. It's a bit like cellulose insulation, all very specialist and can only be supplied and installed by specialists !

I can see how its done without special profiles, just using flat sheets and supported with shuttering but its finding a structural engineer to ok it and sign it off, anybody know one in Devon?????

Posted By: TriassicI can't find anyone who sells the pre-formed edge profiles in the Uk, even though they are clearly on sale in big DIY stores across Europe. It's a bit like cellulose insulation, all very specialist and can only be supplied and installed by specialists !

Yes and no. There are multiple systems on offer that differ in detail so that's unlike cellulose in the UK. Some systems, such as the Passive Slab I have that was supplied by Kore can be supplied as materials only. You can install yourself.

The EPS density and the EPS shapes are cut to the drawings of the engineer who signs off your foundations; Hilliard in my case.

Posted By: an02ewAny good structural engineer should be able to calc the slab design

This is true, but whether they will is another question! The structural engineer who designed the structure of my house and who is perfectly happy designing 'normal' raft foundations, declined to design the passive slab because he's unfamiliar with suspending a slab on EPS. The unfamiliar area was long-term stability of the EPS under load. Visions of progressive collapse of one side of the house.

Posted By: an02ewmy understanding is:

As a reinforced slab there is limited point loading so limited pressure on any one area.
The bearing capacity of EPS is very measurable. ei. 70 grade 100 grade etc.etc
further the slab is bearing on assessed ground bearing condition with a specified amount of stone make up

It's not quite that simple. My understanding is that the load from a particular area of the slab still varies (if the south side of the house is heavier for example). The greater load causes greater compression. Add in creep and there is some potential for instabilities. Anyway, the point is that it's not something every engineer is prepared to deal with and that's why I ended up with a different engineer for the foundation and slab design.

I should make it clear this is not a criticism of my main engineer. He's happy to sign off straw bale houses on a variety of foundations, which is another thing not all engineers will do. Horses for courses.