Hamish

Great many thanks @Russell griffiths

I am in the planning phase for a 6m x 4m detached single story SIP garden room. For which I have contracted with Modular SIPs to provide the SIP kit. The floor layout will involve an internal partition to yield a ~1.5m x 4m garden store and the rest being a workshop. I recently posted separately re some issues I am having getting to certainty on my plan for foundations. However I am also not sure how to best achieve the partition. The options I have are: Use SIPs plus firing to make partition (98mm panels) Construct a stud wall Here again is my current foundation plan (which I am told has cold bridge problems at the sole plate...) Now if I use SIPs for the partition I assume the panels will need to be fitted onto a sole plate which is itself attached to the concrete raft. This will mean that the insulation would need to be installed either side of the partition and would be very much permanent wall. There will I think also be the issue around vertical fitment given that the raft may well have imperfections. With the stud wall I assume I could put the sole plate on the screed and just erect the partition from there. I originally thought the SIP partition would be nice and quick as well as be pretty easy. However I am now basically thinking it is a bad idea. Welcome thoughts on this.

Thanks for replies so far... I found this YouTube video that describes the process. Here is a screenshot from it: Certainly a bit of an effort but in of itself I think it should be achievable. That was my original plan but as my site is in a terraced garden with no side access I am trying to reduce the amount of site excavations, which I am having to do by hand. So far I have not had much luck finding drawings for insulated raft without cold bridging problems that presents an affordable method with excavations kept to a minimum. The isoquick products that @Onoff point out look quality but the necessary excavations just seem overkill for a SIP garden room. Can you point me to any drawings that would a good suggestion? I am intending to use the in-screed cable from Thermosphere, the suggestion on their site is that the cable can be stapled to foil facing insulation boards. I was then going to use a flow screed on top to be the floor finish. @Russell griffiths Is there any method that you are aware of to mitigate the cold bridge within the bounds of my general plan? Looking around other forums I did see one suggestion to use a course of Marmox thermoblock which the sole plate then sits on. However at £200 for 10 lineal meters this seems like an unreasonable expense for my small project.

Thanks, can you point out where, what to change?

Hello, I am new so apologies in advance if I accidentally do not follow protocol... I am looking for some help in "signing off" my plan for the foundations of a detached 6m x 4m SIP garden room workshop. The structure will use SIPs for walls and roof, which will also include some reinforcing steel in order to cater for a green roof using sedum roof tiles (65kg/sqm saturated weight). I wanted to go down the route of concrete raft due to clay soil and wanting to be belt-and-braces in satisfying a classification of being constructed of substantially non combustable materials...due to being sited < 1m from boundary fence. The structure will also be a woodworking shop with machinery installed. I also just like concrete. I should also note that I have already done the majority of sub grade excavations... One of the main questions I have is whether the intention to use a 7N dense concrete block mortared into a rebate in the concrete raft is a sound idea. Although I am using the room as a workshop, I wanted to make sure that future use could be various and as such I am trying to achieve a high grade of airtightness, soundproofing and insulation. For simplicity in the drawing I have left off the vapour barrier and house wrap, as well as internal battens + combo of cement fibreboard/ply and external battens + combo of cement fibre weatherboard + cedar cladding. Any pointers on where I have gone wrong or other suggestions will be greatly appreciated. Thanks for your interest.