Shower Tray Waste Routing

[Hugh Jaleak]

Standpipe will be fine, it's not that that is the issue. If the pipework blocks or constricts downstream of the shower, then the washing machine will happily continue pumping out, only for the water to emerge in the shower tray... To prevent this happening, any NRV (or a HepVo valve) needs to go on the shower waste, before it joins the main run.

I went out to look at a job once, young lady had run herself a rather full bath, enjoyed her soak and pulled the plug, before going into the adjacent bedroom to dress. She came back out to a soaked bathroom floor, and water dripping through the ceiling in the kitchen below. Simply, the water had very quickly found its own level. Being unable to get away fast enough, it had reappeared in the shower, rising up, and overflowing the tray. I told her at minimum, the pipe needed cleaning out, and ideally, bath and shower putting on separate wastes to the stack, to eliminate the problem recurring.

I would also seriously think about putting some access points in the run, with removable panels in the floor above, for future needs.

 

[SproutsDad]

Thanks so much for all this advice. See, there are plumbers and there are plumbers - and I have paid one to design and put all this in, and without a waste NRV, as well as countless heating system leaks on his new pipework with ruined laminate floors as a result.

The plan in this downstairs utility/shower room (for when we get really old), is to keep the shower tray close to the floor, therefore no large step up, for this reason all pipework needs to be inbetween the 100mm joists void beneath the floor. However, I can understand the need for access points to clear such a network of pipes in case of a blockage. I will have new Karndean vinyl tile floor tiles on ply, they can be lifted with no damage. I can probably build in some access points with screw on caps I presume? There will also be some cupboards there which would be good to build such points into the inside, low down I would think.

NRV - This Osma version of the HepVo valve (below link) looks OK, but some reviews say that a CV3 adapter is needed.

https://www.screwfix.com/p/osma-was...od1rsLaQ#product_additional_details_container

This is the one Wickes have, it is actually called HepVo.
http://www.wickes.co.uk/Osma-HepVO-...7WeHY_ejthYus3gSs2saAqBDEALw_wcB&gclsrc=aw.ds
These are about 190mm long so will hopefully fit in to the 40mm run leading from the shower.

This is the adaptor spoken of .......... from Wickes

http://www.wickes.co.uk/Osma-HepVO-CV3-Waterless-Waste-Running-Adaptor-40mm-white/p/149143

>> Reference my earlier sketch of the extended 50mm main run, will that be OK?
While I am at it extending the 50mm main run to include the shower, should I take it all the way to the washing machine? Or at least to the last bend, leaving just a short piece of 40mm into the standpipe?

Please confirm and thanks again for sticking with me on this., much appreciated.

 

[Hugh Jaleak]

Just buy a genuine HepVo valve, plenty available from merchants on eBay, at a lot less that those prices too.

Access, I'd as a minimum, put something on the end where the washing machine waste turns right across the room.

I'd take 50mm from where the shower joins the run, leave it at 40mm from the washing machine to that point, hopefully then that section will be pretty self cleansing. Going to 50mm past the shower gives you extra capacity when the washing machine discharges, if the water cant get away quickly enough. Hep valve will prevent any reappearance in the shower theoretically!

Seen so many showers, with pipework buried under floors, and no access, when its proved easier to pull the ceiling below down to get at the problem, rather than destroy the room above. A little short term forward thinking for any future problems can save a hell of a lot of mess in the long term.

 

[SproutsDad]

I bought the HepVO NRV from City Plumbing and it turns out that Osma own Wavin so the HepVO valve and Hep2O pipe are all Osma owned. I got the valve, plus the straight threaded connector that should probably be a part of the valve kit as everyone complains that they need to buy it anyway.

HepVO looks quite small (180mm long) so what do you think about the sketch overlay for option A or B shower pipework layout with this valve?
I favour option B if I have space and can get the required fall.

You mention having to rip out a ceiling to gain access from below, I won't have that luxury. This is on the ground floor and all this pipework is in a 100mm void with concrete underneath, joists and plywood above.

The builders are coming back next week to finalise the T&G plywood floor. I will tell them to just dry fit it, I can glue and screw it down later, after I have incorporated small access areas within the floor to get to the pipework. I don't want it rushed, this will be closed in forever!

Your opinion please?
Thanks