Sleeper walls gap

[pauld04]

Hi all,
I'm self building a rear extension and have a quick query regarding sleeper walls. On one side I have a vertical waste pipe so it would mean that my sleeper wall is only about 45mm away from the existing wall and I wanted to check if this was enough. (I'm using sleeper walls as this was BCO s suggestion due to the dpc level sitting mid joist height.) The wall will consist of a course of honeycombed concrete commons cut down to get a half brick height ,2 courses of honeycomb brick with dpc then plate on top.
My other question was does this final course need to be a full course rather than honeycomb in order to seat the dpc properly or would I dpc each brick then bed plate that way.
Thanks for any help recieved!

 

[George_engineer]

Why not just stop the sleeper wall where the soil pipe is? You won't be able to sit a joist on it in line with the soil pipe anyway (may need to put a small trimmer in and form an opening, depending where the joists land).

Usually top course is continuous but depends how many courses there are. If you want to keep gaps then you could put a timber wall plate on top so you can nail the joists down onto the sleeper wall and not worry about the gaps. Get treated timber and treat the cut ends.

 

[pauld04]

Thanks for replying George.
Reason for wanting it over the pipe is because one of my joists lands right over it and I was trying to keep the joist layout simple to fit in underfloor heating insulation (stuff that has the pipes laid into it) although sure I could work around the trimmer. If the sleeper isn't too close to existing wall at 45mm then by the time sleeper and wall plate are on I should have enough clearance between joist and top of soil (this currently has a manifold with the temp kitchen running into it but will eventually just have a single socket drain connector in it with one 40mm waste into it) hence wondering if I'm too close to wall as that would be ideal solution.
The continuous course for plate makes more sense in my mind, it's basically 1 course of 50mm with gaps, 1 course of 80mm with gaps then the final course of 80mm no gaps.
Thanks again.