Toilets- S traps, P traps, holes in the floor...

[Crofter]

My soil pipe is coming up through the floor, and I want the WC to sit right over it.

Do I need to find a specific S-trap type toilet, or can I use a (apparently easier to find) P-trap one, with a bend immediately after?

I still have a little leeway in the exact position of the soil pipe, but not for much longer...

[Tennentslager]

Buy a back to the wall WC and hide it all. Not much more cash and easy to clean

http://www.wholesaledomestic.com/bathroom-suites/toilets/back-to-wall-toilets

 

Edited September 25, 2016 by Tennentslager

[Nickfromwales]

What's the vertical drop between the wc outlet and the bend in the soil run ( to horizontal ) ?

[Nickfromwales]

Oh, and +1 on a back to wall wc . 

[Crofter]

9 hours ago, Nickfromwales said:

What's the vertical drop between the wc outlet and the bend in the soil run ( to horizontal ) ?

 

Pretty far- through the 300mm suspended floor, then another 200mm or so where there is a fitting to take all the side branches (basin, shower, etc), then it meets the rest bend and transitions to horizontal underground...

[Crofter]

9 hours ago, Nickfromwales said:

Oh, and +1 on a back to wall wc . 

 

Do these always entail a hidden cistern? Would rather avoid that as the room is quite small and it would presumably need a lot of boxing out.

[Tennentslager]

Google 

Back to wall toilet with cistern

http://www.bathshop321.com/tilly-back-to-wall-close-coupled-wc-toilet-with-cistern/?gclid=CjwKEAjwjqO_BRDribyJpc_mzHgSJABdnsFW_RIrOjCxJLejr26hTe3hM185j9sk3h_cs2YxiXafJRoCK-3w_wcB

[Crofter]

Thanks, that looks neat. I presume I could just stick a 90 adapter onto the back of the outlet of that WC and then it would be able to go down through the floor? And of course all hidden from view!

 

Edit to add: I'm leaning towards this approach as it presumably allows a little flexibility in the precise positioning of the WC and soil pipe, whereas an S-trap will have to be bang on the right spot, no?

[Tennentslager]

I'm sure Nick will advise but I used one of these

http://www.screwfix.com/p/mcalpine-wc-f26r-flexible-wc-pan-connector-white-97-107mm/71219

This meant I could attach the waste to both the pan and the pipe (with the pan angled to the side to get access) them wriggle it into place.

It also means it's a bit more forgiving as you don't have to get the rigid soil pipe dead on.

 

[Crofter]

So I'd be looking at using something more like this:

http://www.screwfix.com/p/mcalpine-wc-con8f-90-flexible-pan-connector-white-110mm/28262

 

To make the turn down through the floor.

 

It looks like it's a question of choosing a WC that has enough space at the back to allow this- e.g. the one you linke to upthread gives 140mm but my interpretation of the specs on the connector above is that it needs 153mm... but this ought to be a solvable problem. Was just wondering if it's better to find an actual S-trap type toilet instead.

[Tennentslager]

There will be plenty room?

I'd buy the bathroom kit/WC and dry fit before you cut a hole in the floor. Easy peasey that way

?

If you put one of these in a vertical pipe you have height adjustment for final floor level. The trick is to get the ceramic fully/mostly in the rubber fins but still get the WC to touch the wall.

 

http://www.toolstation.com/shop/p37429?table=no

 

[Nickfromwales]

Is it only the WC onto that vertical rise? 

Your allowed around 1300mm before you really need air admittance so you should be fine with a direct termination to the WC. 

Any standard WC will have 7" centre for the outlet and enough room for that flexible bent pan connector. Personally I'd recommend a solid unit as that flexible one will end up under floor level where it changes from flexible to solid. Making that off to the finished floor will be a challenge for you that I'd rather dodge . 

Mark the WC centre and bring the soil up according to the WC of choice. Of course, that means buying it now but I wouldn't suggest any other way if it were me doing the job.

The rigid bent pan connectors can be cut to length and will allow you to bring the 110mm pipe up through the floor slightly and then you can seal up with ease against rigid pipe instead of fragile flexible pipe. 

That make sense?

[TerryE]

You could also happily use 80mm pipe and fittings for this. 

 

There's also nothing to stop you sightly over-sizing the hole to give yourself some wiggle room  and then just foam and silicon seal it in (this would all be hidden by the back to the wall). 

[Nickfromwales]

I'd not recommend 80mm myself, when you can use 110mm with you having no real reason to deviate from 'standard'. 

Wall hung ( Geberit etc ) have 80mm pan connectors but they increase to 110mm within 300mm with the supplied adaptor. That takes them to 'our standard' from European standard. Our pan connectors are narrower bore anyhoo so 6 and two 3's imho. 

[TerryE]

Nick, you must lay some huge turds if 80mm is too small for you 

[Nickfromwales]

The biggest shits will be the bco's   

[Crofter]

6 hours ago, Nickfromwales said:

Is it only the WC onto that vertical rise? 

You're allowed around 1300mm before you really need air admittance so you should be fine with a direct termination to the WC. 

Any standard WC will have 7" centre for the outlet and enough room for that flexible bent pan connector. Personally I'd recommend a solid unit as that flexible one will end up under floor level where it changes from flexible to solid. Making that off to the finished floor will be a challenge for you that I'd rather dodge . 

Mark the WC centre and bring the soil up according to the WC of choice. Of course, that means buying it now but I wouldn't suggest any other way if it were me doing the job.

The rigid bent pan connectors can be cut to length and will allow you to bring the 110mm pipe up through the floor slightly and then you can seal up with ease against rigid pipe instead of fragile flexible pipe. 

That make sense?

 

Right... bear in mind my house is a 'portable building' sitting up on piers and open underneath. The sewer pipe runs horizontal underground, under the building, to a rest bend, and then vertical straight up out of the ground and up to where the WC will be. Just under the floor there is a branch fitting where everything connects- the SVP stack, the kitchen run, the basin, and the shower- this is part of the vertical rise. This fitting fits just, and only just, under the 'subfloor' of the house (a layer of OSB boxing in the bottom of the joists and supporting/protecting the insulation).

 

Ideally I want the soil pipe to come up through the chipboard floor via a nice neat hole that will be easily sealed (the chipboard will be the airtightness layer). So solutions that involve diving down into the structure of the floor are less appealing, but I suppose I could go that way if necessary. I think all I will need is a fairly short 90 degree connector and a compatible WC design.

[Nickfromwales]

As per my last then

Any rigid pan connector can be cut to make it 'short', but a flexible one cannot, thus forcing you to make the connection sub-floor level if you chose the latter.