Shower waste in celotex insulation

[mordzy]

Hello. I’ve been laying down some celotex in my extension ready for UFH and screed and it’s just dawned on me that once down I’d be a bit stuck for any waste other than sink and wc above the floor.

Is it ok to cut a channel in the celotex and run a standard plastic pipe along and out the wall? The cello text is about 150mm thick and the distance to wall is less then 2m.

Thanks

 

[John D v2.0]

Yes it's fine although try to leave at least some insulation to avoid thermal bridging
Also 150mm seems like a lot, are you going for super insulated?

 

[mordzy]

Yes, I’d originally planned for 100mm but went higher so that the floor could be level between the older part of the house and new. Figured more was better anyway. I figured I’d make a 1ftx1ft cut in the 50mm celotex and shutter the outside to prevent the screed flowing in. Then run the pipe out with a small ‘fall’ to the wall. Perhaps 10-20mm overall which would mean it’s still sat in the 100mm below.

Thanks for the help