110mm soil pipe locations through raft foundation - how to site accurately and how many do I need?

[markharro]

Hi I am hoping to get some quick steer on this as our insulated slab installer needs this detail during the course of next week. I have attached 2 drawings - "warrant drainage" is what the architect shows and "slab penetrations" is the schematic provider by the slab installer. It shows the scheme as they have currently provided showing what is currently provisioned in orange. Maybe @Nickfromwales might be able to help because I am still struggling having had input already from our architect/engineer/plumber etc. My questions are as follows - 

 

1 Starting with the shower-room at the top we still need to give a location for drainage for the shower tray. We haven't yet decided on trays so this is causing an extra complication but if we assumed that we end up choosing one with a central drain do we just ask for a 110mm drain pop up under its eventual location? My concern is how can the pipe be located accurately enough during the slab pour?

2 Staying with this shower-room we plan a wall hung WC. There is nothing shown atm for its drainage (nor for the sink) on the penetrations drawing - is this because it simply goes within the bulkhead above slab level as shown on our architect's warrant drawing?

3 In the central shower-room again we have no shower tray agreed yet we need to confirm an exact location for the drain pop up. Again my concern is mentioned at point 1 above.

4 Staying with the central shower-room the drawings show a wall mounted sink. We have actually bought a free-standing pedestal sink that connects to a drain and is plumbed for water from underneath. So this will need a drain pop up as shown on the schematic. But again what about the WC and (possible) urinal. The architect shows these in a bulkhead but because we now have the free standing sink and this room is quite small I would prefer to avoid or minimise a bulkhead. For that reason I am thinking about this specific WC - https://catalog.geberit.co.uk/en-GB/Geberit-Monolith-sanitary-module-for-wall-hung-WC,-114-cm,-front-cladding-made-of-glass/PRO_224758.html?_gl=1*1h93qrg*_ga*MzIxMjMwNDgyLjE2Nzg2MTk2ODE.*_ga_GK4EZNK9CL*MTY3ODYxOTY4MC4xLjEuMTY3ODYxOTg4Ny4wLjAuMA..

If I used this it looks like the drainage goes horizontally back into the interior wall first. Would there then need to be a 90 degree bend and a connection to a pop located within the wall. Again how can I be confident that this will get placed with enough accuracy during the slab pour?

5 The utility room sink (to right of central shower-room) - is this drain ok?

6 Finally the kitchen sink at very bottom has changed drainage from what the architect had shown as we have a very marginal fall and the new drain line under the slab gives the best solution according to our groundworker for this reason.

 

Any comments on this gratefully received as feeling under a lot of pressure atm to get this understood and right.

 

thanks,

 

1400 - Slab Penetrations (4).pdf Warrant drainage.pdf

[markharro]

Anyone able to offer any comments on this?

[Dave Jones]

keep the 110 outlets where they can be hidden under units etc. For shower trays don't worry too much as the plumber can grind out a channel for the waste. Some like the outlets in the middle some at one end.

 

Try to lose vertical pipework inside stud walls so you don't have boxing in anywhere which looks crap (same with wall hung toilets always in studwork where possible).

[ETC]

Not sure if this helps….

[markharro]

Thanks @ETCthis is totally different to what the architect AND groundworker are indicating though which is now thoroughly confusing me!

[Nickfromwales]

 

You only need foul ( solids / food waste ) having line of sight of the inspection chamber, and having clear running ( other bathing / waste ) water branching in ( with Y branches ) is perfectly acceptable.

[Nickfromwales]

You simply drop blocks of 100mm EPS into the slab, prior to the pour, as shuttering. If it's too complex an area to do that, then I just fill the area with sharp sand and get the concrete poured up to / against that. Then use Henry to suck the sand out after the pour, sort the trays / wastes etc, and then back-fill with cementitious SLC or a sloppy concrete mix, whichever works.

Tie down any EPS shuttering blocks VERY well as they'll really want to rise during the pour.

[Kelvin]

27 minutes ago, Nickfromwales said:

 

You only need foul ( solids / food waste ) having line of sight of the inspection chamber, and having clear running ( other bathing / waste ) water branching in ( with Y branches ) is perfectly acceptable.

Exactly how we’ve down ours. The architect drawing was really poor by comparison