UFH pipes through doorway foundation?

[hotnuts21]

Hi, I have a timber frame extension on a block foundation, including one of the internal walls. 

 

There is a doorway in this wall, and most of the UFH pipes flow through this doorway from the utility to kitchen etc. 

 

However as the dpc on which the sole plate sits is nearly the same level as the finished screed, the UFH pipes need to go through the block under the internal doorway? How is this normally done? 

 

Photo for clarity between kitchen and utility. (I still need to cut away the sole plate timber at the door. 

 

In fact this doorway is going to be a cold spot as the screed will only cover it by 5mm. 

[hotnuts21]

Not sure they help but some other photos. This is the external door.

[Temp]

If there isn't going to be a wall plate under the doorway you don't need blocks to support it either. I would remove a course or half a course of blocks and make good the DPM so you could run UFH pipes and screed through the doorway. 

 

However..   You should put an expansion gap in the screed at the doorway, not just screed right through. The screed in each room will shrink very slightly towards its own center and may settle a bit. This can crack the screed at its narrowest point which is where it meets at the doorway. If it cracks there is no guarantee it will be a straight crack. The crack can be curved into one room. Worse it can propagate through any tiles you put down. Don't ask how I found out. The expansion gap acts like a deliberately straight crack and you can later cover it with a sill tile or arrange for a grout line to be above it. You coukd form the expansion gap using two bits of plywood with u slots in one and n slots in the other for the UFH and other pipes to pass through. Just needs to be fixed so the screed doesn't move it. 

[hotnuts21]

Great thanks, is there any special rules/regs with making good the DPM? I can carefully slice it and fold it back to cut the bricks away. I now need to find a recip saw blade I can cut the blocks with!! They are hefty!

 

Thanks
Paul

[Temp]

Just find someone good at wrapping Christmas presents. After lowering the blocks I think I'd put something down to protect the DPM from the rough edges of the blocks. Perimeter insulation roll would probably do. Then run a strip of DPM through the doorway and use DPM/C jointing tape to seal.