moving bath waste in concrete floor

Hi

Have been reading previous forum answers but wondered if anyone could help.
I am going to move my bath (downstairs bathroom with concrete floor) to the other side of the bathroom. The problem then is that the bath waste outlet will not be under the bath. The waste currently comes straight up out of the concrete (40mm plastic pipe) and then has a bend and the pipe linking it to the p trap under the bath.
I spoke to someone and he said that by digging out the floor and solvent cementing the new waste it would be possible to fit a bend to the existing pipe, run it the 40cm or so to where it needs to come out under the bath, then bending up again (so it emerges from the concrete) to fit the new bath waste pipe into.
Does anyone have any suggestions on this. Will solvent joining be OK on the pipes in the cement? How deep would it have to be dug down to get a fall from the old pipe to the new outlet? Would a 92 degree bend be sufficient rise from the old pipe. I thought this could then go to a 90 degree to come up from the floor then another 92 to rise to bath.
All thoughts gratefully accepted.
Oh and I'm not bothering with the soil pipe that comes out of the concrete! Just boxing in behind the toilet!!

J.

I dont really follow your description.

However you really only have two choices, a false floor 100 mm thick to contain the pipes, or a lot of chipping of concrete.

Tony

Hi thanks for response - it is a bit confusing. We will have to dig out the concrete (what fun!) But I just wondered if anyone had any advise about running a 40mm plastic waste in concrete. Will the cement weld be ok?

Also, when it comes out of the concrete floor in it's new position what degree bend should be used? I was thinking 92.5 in order to give a fall from the bath trap to this new piece of pipe.

Thanks!

yes, solvent cement and 92 bend ...then cover it with maybe..bubble wrap- to stop new concrete gripping the pipe..ie. let it expand/contract as it wishes

Thanks - bubble wrap is a great idea!

Also going to move the 22mm copper pipes which come up through the concrete floor. Annoyingly they only have to be moved about 2" !!
Going to swap to plastic pipe when it hits the surface but is my option if i do this to dig down and solder a bend to the pipes then bring up new copper in the right position. If so what do I need to wrap the copper in, and is the soldered joint best or would a compression joint be better?

OK,

Possible change of plan!
There is the current 32" sink waste (also emerging from the concrete floor)which when the bath is moved will be under the bath. Would it be possible to use this for sink and bath waste and cap off the old 40" waste pipe and bury it under the floor?
If so the choice is now should we get all the floor dug up (to move the 40" pipe) or go for the compromise of connecting into the 32" waste for the bath and sink? Bath will be downflow of the sink.

Thanks!

You shouldn't use 32mm for the bath.

Thanks Dan,

I was afraid you might say that! Digging up the floor it is then!

Thanks for all your help! Will no doubt be back with more questions!

Would it be easier to dig up the 32mm pipe and replace it with 40mm?

Depends on location of pipes etc - just a thought.

Doh - just realised this is 6 months old!