Basin waste under concrete floor

[DIYer Dave]

Not sure if this has been discussed before but I’m wanting to fit a shower on a concrete floor in a bungalow, not an issue in itself.. However because it’s such a small bathroom I can’t move the basin and therefore I’d have to cut into the floor screed, and probably the concrete below that, in order to have some fall on the basin waste and also to accommodate the hot and cold copper piping which will have go under the shower tray (all of which are currently running above ground down the side of the current bath).. the run of the waste pipe will be approximately 2m to a corner then another 2m to the waste stack, is this on..?? I’m looking to see if anyone else has had to do the same thing or similar….or indeed if anyone has any advice. BTW it’s not an option to put a false floor in and also I don’t really want a shower bath..!!!
Dave

 

[oldbutnotdead]

Long as there isn't underfloor heating or other buried pipework/cables it'll be fine. Personally I'd cut trenches in the concrete for the waste and other pipework and leave the trench open (or use expanding foam). Keep any inaccessible joints to a minimum (ideally zero) so look at solvent-weld waste and either soldered copper or continuous runs of placcy.

 

[Hugh Jaleak]

Upsize to 40mm after the first couple of metres, make sure all waste runs are accessible for cleaning should (when) need arise(s). Use solvent weld and ensure pipework is watertight before burying.

Water supplies, I'd use plastic pipe, and one continuous run under the floor, ideally in trunking to allow easy replacement should it ever need it.

 

[DIYer Dave]

Thanks guys, very helpful. At least I now know I’m not stupid for thinking of doing it..
Thanks again
Dave