Hi. I know that there have been lots of discussions on this board previously about SIPS constructions and the risk of cold bridges and condensation around the soleplate. I've read lots of these and have asked our architect, the SIPS provider (and through them, Kingspan) to focus on the soleplate detail.

They've come up with the solution in the attached image... and I was wondering if any 'experienced hands' out there had a view on what they are proposing

In summary, the solution involves:
* Soleplate rests on 65mm Foamglas Perinsul HL
* Which in turn, rests on our Forticrete blocks
* On the inside, there's 25mm on Celotex against the SIPS panel and soleplate, increasing to 50mm further down (next to the Foamglas and Forticrete blocks

All comments v welcome indeed. Thank you

One issue is that with UFH the floor will be a lot warmer then is normal, therefore any cold bridge has more effect on running costs.

The fixing of the sole plate will give a thermal bypass of the foamglass, I don't know how much effect it will have.

Is there a reason you can't have insulation on the outside of the sip panel going down to the bottom of your foundation?

This will be close to what I am doing:

And the thread that it relates to is here: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10226&page=2#Comment_222874 You may have gone through that already.

Posted By: tonyLooks good, chamfer top of eps and breather layer to go over it

I have breather membrane on the SIPS already that continues down below the sole plate. I guess there is no harm in adding a further membrane over the EPS to keep any water well away from sole plate.

Posted By: tony

Might not need 75 void and I would like to see brick slips going up behind the cladding please

Yes, 75mm does seem excessive and I've never liked the bulgy look of the slips protruding at the bottom so will have them pushed in level or behind the cladding.

Posted By: tony
In my view 25 mm min space for ventilation and free passage of water down in that void

Which void? I was going to go for 50mm EPS to cover the sole plate and wanted a big enough void between that and the slips/cladding for air to circulate. Think that's why I ended up with a 70mm void. Guess PIR would be an option but the breathability of EPS is better in this location. Could I uses another insulant? Aerogel??? £££ but breathable?

Sorry to hijack the thread SGS!

Interesting about adding the external EPS and a fairly cheap addition. Here is our plan. Our outer has to be real stone as we are in a National Park (though in fairness I wouldn't have built in anything else anyway as it would just not look right there, with a Norman church and 16th century fortified pele tower both within a stones throw, but actually by using recycled stone for environmental purposes, it happily pretty much turned out as cheap as fake stone slips would have anyway). Not shown, there is also 100mm of Kingspan going on the inside then double plasterboard. There is a DPC and so on but it doesn't show up in this scale.

http://www.ukradon.org/information/ukmaps#