Toilet Soul Pipe for en-suite

[Jack-Regan]

Hope someone can give some sound advice.

I am working on the idea of installing an ensuite shower, with toilet and hand basin in the bedroom.

The best installation for practical use has the back of the toilet up against the adjoining house wall, which would require the soil pipe to go down though the floor at the back of the toilet, then go through a u bend to take it forward under the toilet (below the floorboards obviously) with a run of approx 1 metre, then a left-hand 90 degree bend into a straight run of 4.5 metres, then a riight hand 90 degree bend followed by a 30 cm run to join with the soil pipe from the bathroom toilet. all horizontal, of course, or I guess some fall could be created as there is obviously some leeway under the floorboards.

Is that remotely feasible?

All advice gratefully received

Cheers,

 

[Mr millimetre]

Hi not ideal with the straight runs but that leeway you mention might be enough to float away what it needs to,but could become a toilet that slowly drains or blocks who knows! Try it get a toilet with a flush pipe at the back so you can have a good fall on the flush with a higher cistern,unlike close coupled! Good luck.

 

[Hugh Jaleak]

You just come in under the 6m maximum run allowed for an unventilated branch, but I am concerned about the number of bends involved, and the fall. Could be a recipe for disaster, if it blocks up, its not going to be an easy mission to clean it out. Secondly, you need a minimum 18mm per metre fall to satisfy regs, is that achievable?

 

[Jack-Regan]

Thanks guys.

No, I know it is far from ideal, and the fall req, Hugh, may just be achievable - 9.54cm over the entire length?

Maybe back-to-the-wall type toilet would be good - they usually have a higher sited water tank,, which would give it a more powerful flush, I imagine?

I think it may be possible to put a small angle from the initial outfall so that instead of running straight out from the toilet it runs away to the right (seen from the front of the toilet) and down by the req 18mm before it joins the long run, which may aid the flow, and reduce the pipe run slightly.

I'm wondering now how original builds work with an en-suite on the front when the bathroom is on the back of the property....?

Whatever, I'm thinking it isn't a toilet you could use a short flush on

 

[Hugh Jaleak]

If your building from scratch, you can put the drains where you need them, i.e. under the bathrooms! Drains would be laid through the foundations prior to the oversite going in, then the plumbers can run the stack up in a corner to serve the bathroom above, once boxed in and decorated, hardly noticeable.

Its when you come to retrofit a bathroom or WC in an existing building the fun starts, as you're finding out....

 

[Jack-Regan]

If your building from scratch, you can put the drains where you need them, i.e. under the bathrooms! Drains would be laid through the foundations prior to the oversite going in, then the plumbers can run the stack up in a corner to serve the bathroom above, once boxed in and decorated, hardly noticeable.

Its when you come to retrofit a bathroom or WC in an existing building the fun starts, as you're finding out....

Ah, yes, that makes sense.

Just been back with the tape . . .

We have approx 18 cm between floarboards and ceiling below - so fall can roughly double beyond regulation minimum, and depending on where the joists are located, the long run can be angled by around 30/35 cm to the right, which will bring it out to the right of the original bathroom toilet, cutting out the last 30cm run and dump straight into the side of soil pipe that goes into the corner of old hot tank closet and down the stack and out.

So that way waste water is going through shallower bends,, with more fall, and always going away, and down at the same time, until it meets the original soil pipe.

Does that sound better, or have I fallen into the trap of wishful thinking?

 

[Jack-Regan]

Rethink:

Measured up again - The toilet will just go on the opposite (internal) wall. Dumping waste water etc downwaards and I think just a 60/70 degree bend (don't know what is available) into the 4.5 metre run with approx 35mm fall per metre and dumping straight into the side of the original soil pipe from the bathroom into the stack. Cuts out 1.3 metres and contains only two bends after the down outlet (as per the original)

 

[Hugh Jaleak]

Ideally aim for a 1:40 fall, (25mm per metre), too steep a fall can be as bad as too shallow a fall. Bends, 45 and 90's are available, anything else and I think you'll need an adjustable bend. Horrible things but if needs must.... Not 100% sure how the run will work, but if you're heading to an external stack, fit an access bend where it comes out the wall and turns to join the stack. Never know when you might need it, and better trying to clear from outside!

 

[dilalio]

Also, if you're going for a back-to-wall pan with a concealed cistern, inside some boxing, which can be tiled/decorated, put the cistern high up in the boxing and also put a stub-stack in there, with a durgo on the top (above flood level of basin).

 

[Nige F]

And if you look @ underground plastic fittings ( brown in colour) you will find easy bends and various angles. They will be fine away from daylight - it degrades the plastic.