Planning a new passive house commercial building. About 10 m X 15m on a brownfield site. Present building being demolished now. Has anyone done their own passive slab? If so how, and where did you get the materials. Can you get a way with just a 100mm slab with a deeper ring beam? The building is going to be timber framed. Not sure whether I beam or twin walled. any suggestions there also appreciated. Thanks.

Posted By: bogal2Can you get a way with just a 100mm slab with a deeper ring beam?

We have an Isoquick PH slab. I wanted 100mm concrete slab with deeper ring beam but the structural engineer vetoed that idea and said we had to have a 200mm slab because of ground conditions. We have 250mm compacted type1 then 50mm granite fines then 300mm EPS(Peripor) with a 200mm thick upstand.

@bogal2,
I went for XPS as it was :
cheap
available
easier to cut
dense/suitable
T+G

Others here will advise EPS. S'up to you...
With TF do you need a deeper 'ring beam'?
V easy to lay down, and keep on top of details!

Posted By: bogal2Did you install it yourself Peter?

No, it was the first Isoquick installation in the UK and a German technician came over to oversee the work. Unfortunately the UK groundworkers weren't up to the job the first time! In fact installing the sub-base and EPS is DIY because it fits together like a jigsaw puzzle. It was the UK concrete workers who were hopeless. There's a bit in my blog about it.

http://eastkentpassivhaus.blogspot.co.uk/

Posted By: djhI bought the EPS from Kore in Ireland and Tanner Structural Design did the engineering design.

This brings back memories, In 2001 I had a few Estonian workers who mentioned houses they'd built on EPS in Scandinavia, I was curious so went to Sweden for 6 weeks working for an Insulated Foundation company. In 2002 I brought over renowned Swedish EPS Engineer Eric Thalberg to meet a few young Irish Engineers who had just started out on their own, Hilliard Tanner was one of those but there was also a few others, we also visited a few EPS companies, Kore was one. We educated them on EPS grades, the risks, the loading's, the long term creep and so on. The first few Passive Slabs we installed were jointly signed off by the Irish and Swedish Engineers until the Irish Engineers got comfortable with the system. We had many early problems with ring-beams becoming exposed at door thresholds and radon barriers but no structural issues in close to 1,000 foundations.
The double L was one of my early innovations that solved the Radon Barrier issues, but the ring beams were still an issue. I solved this by combining the Passive Slab with the Twin-Stud, it took a few months to convince the Engineers to only use the inner stud as the load bearing element and let the outer stud hang over the EPS and just hold the insulation. We tried I-beam and regular Timber Frame on the Passive Slab but these had to be built on a ring-beam as wide as the wall so the ring-beam was often exposed, the best method is to bring the load bearing element to the inside.

Posted By: djhYes our ring beam was very unusual because the bales and render need full support. So the ring beam is separate from the slab, although tied to it for stability and the bales are cantilevered over the EPS uprights by a timber upstand.

I wouldn't have used a ringbeam in your case!

You can still "cantilevered over the EPS uprights" without a ring bream.

You could have built a Thickened Edge Passive Slab, stood the structural Timber Frame on the edge of the slab and installed the bales afterwards, no need for a ring-beam and less risk of cold bridging.

Ok, is the ringbeam exposed at the door threshold then?

Posted By: fostertomWhat a story! Great that for once you were able to enforce drastic re-making of substandard construction - too often we find no alternative but to live with it. The concreters must have taken quite a hit.

Cost cutting by not using a pump seems strange, unless they had several unpaid bods available, esp on a straighforward single pour without fiddly manual bits.

There were three workers and it would have been so easy if they had just used a pump in the first place. I think the hit was taken by the concrete suppliers but not positive. Fortunately having a video of the whole process meant they didn't have a leg to stand on.

Posted By: MarkyPIn your case Peter am I right in recalling they did it with wheel barrows?!

That's right, wheel barrows! They were mad, just to save £300.

I employed the company, who at the time were the only installers of Isoquick, to do the foundation system. They were my point of contact and they employed the concrete layers. The company had a contract with a concrete supplier but I think the concrete supplier's lorries were travelling too far and as a result the concrete had started to go off too early.