SIPS foundation critique

[Clark Kent]

Hi

 

Would be grateful for any feedback on these details. It's for my own extension, first time doing building detailing etc so if there are any schoolboy errors please let me know.

 

The build is for a SIPS extension, I know it's probably very light but the proximity of neighbours tree means I've had to go deeper than standard.

 

I've attempted to design out any thermal bridges, hence the use of a Marmox Thermoblock....hopefully this will mitigate any danger of condensation on the sole plate that I've read about.

 

Thanks for the help in advance!

 

 

Edited February 28 by Clark Kent

[Redbeard]

From the Section dwg: Yes the sole plate is isolated by the Marmox block from the cold ground but there appears to be no mitigation in terms of the horizontal plane. Seems to me cold comes from outside in, and voa the screed, with no insulation in the way. Have I misread that?

 

OK; could be wrong. There appears to be, un-'tagged', 25??mm of Kooltherm or equiv as an upstand at the edge of the screed. It's not much, though, and still seems not to do anything re transfer diagonally upwards from outside. Have I missed something?

[Clark Kent]

@Redbeard thanks for replying. There's 50mm EPS/PIR up to the Marmox black. It's un-dimensioned currently though

[Redbeard]

42 minutes ago, Clark Kent said:

There's 50mm EPS/PIR up to the Marmox black. It's un-dimensioned currently though

 

But I think that is under the Marmox Block. I am talking about the heat-loss path if you draw a line diagonally downwards to the right from above the screed in the room on the left, through the sole plate, past the 'plinth stretcher blue special shaped brick' to outside. All you hit is plasterboard, wood, brick. No insulation.

[Clark Kent]

it's pretty hard to see as the scale is quite small but I do have a 25mm PIR up-stand at the edge of the screed. I Guess I could bring the 50mm EPS/PIR up to/slightly higher than the sole plate.

 

I haven't had any design drawings back from SIPCO yet but their standards don't show anything to insulate sole plates. I did wonder how these work in reality, you have a nicely insulated SIP panel just nailed to a pice of timber which is fixed to an existing outer wall.

 

Even if you we're building an entire new build out of SIP's you would have lots of similar details like this at corner junctions and window reveals etc so I didn't think the sole plate would be a massive cold bridge. In fact, do I really need to use a Marmox block?!?