soil pipe plumbing

[Stephen]

Hello,

I've been looking to buy a terraced house. In many of them, the bathroom was originally downstairs behind the kitchen and over the years, owners have converted a bedroom into a bathroom. I was thinking it must be harder doing this work to a terraced house as you cannot run any pipes along the side of the house (though with a semi detached you only have access to one side).

I guess if the property had a front or back garden you could try and install a new soil pipe but often terraced houses open straight onto the street, which I guess means adding a soil pipe to the front is out of the question.

Could you add a bath, basin, or shower to the front of the house if the soil pipe was to the back? I am thinking that you could fit 40mm waste pipe under floorboards if the joists ran the right way (front to back but I guess they probably run side to side). But even if the joists ran the right way, would you be able to get sufficient fall? If the joists run the "wrong" way, I wouldn't feel keen on notching joists.

At least 32mm or 40mm pipe is small enough to run under floors or along walls. I'm guessing this isn't possible for 110mm pipe. Does this mean that the only way to fit a toilet to the front of a terrace house is to use a (dreaded) saniflo?

Thanks, Stephen.

[Tricky Dicky]

In terraced houses joists usually run from front to back, this avoids problems with party walls especially if they are only one brick thick as I mate of mine discovered when drilling into one only to go through into next door.

Richard

[chris French]

In message , Stephen writes

A soil pipe was added to the front of our house at some point (not terraced, but a pretty long frontage straight onto the pavement) But this would have been installed sometime ago, the bathroom that was in there dated from the early/mid 1990's but not sure if that was the first one installed there (non in the original Victorian house, first bathroom installed in another part of the house in the 1960's).

Alternatively run the pipes fixed to the wall above floor level and box in? We are planning the next bit of refitting of the house, which will entail an ensuite in the room next to the old bathroom. The only way to get the pipes to the soil pipe on the front of the house will be to run them about 4-5 m along the wall inside through the neighbouring room.

[JimK]

/ Alternatively run the pipes fixed to the wall above floor level and box i n? We are planning the next bit of refitting of the house, which will entai l an ensuite in the room next to the old bathroom. The only way to get the pipes to the soil pipe on the front of the house will be to run them about

4-5 m along the wall inside through the neighbouring room./

How many steps upto the bog?! :-) Jim K

[Andrew Mawson]

Far more likely that there was no bathroom at all when originally built. There would have been either an outside toilet, usually outside the kitchen, or a privy at the bottom of the garden depending on the era.

Andrew

[Tim Watts]

Everything you need to know from a regs POV are here:

(Part H)

If your joists ran front to back:

The minimum slope of any drain inside is 18mm fall per metre (Dia 3, Page 9 in the above doc).

So if you have about 5" to play with (50mm pipe in 8" joists) yoi have a max run of about 7m.

In practise you can get away with a little less (I did) on 50mm pipe as long as it is consistently falling (no "dips" that trap scunge) and you have rodding access just in case. I'd say 10m is not really a problem but it's not quite up to Part H.

So Bath/basin/shower no problem - there's plenty of fall available assuming 8" joists. I would use 50mm pipe for the main run and include an allowance to let it expand (uPVC does, a lot, when hot water goes down it). This could be achieved where it does the 90 degree bend to come up through the bathroom floor - allow that entry to be sloppy to allow movement.

Toilet - you didn't mention, but I wouldn't. Less fall to play with and you really do want a decent fall on soil pipe.

If your joists run counter, then you have really 2 solutions:

1) Sump+pump (like saniflo but less horrible). This is a standard solution but it's not my favorite.

2) Drop 50mm pipe down through the ceiling and run it along the room wall front to back. Box it in. This is actually a reasonably stadard solution.

HTH

Tim

[Tim Watts]

Good option (3) (WRT to my 2 offerings of sump+pump and run below the ceiling). I did not think of this as I was assuming a shower was involved. It's just about possible to get the required fall (almost) for a bath - I have one running above a solid floor).

[harryagain]

When things get really tricky, the normal solution is to ave a macerator,which chops everything up and pumps it to wherever you want. You can get one that fits right on the WC outletpipe.

[Bob Eager]

Only if he's truly desperate:

[Tim+]

Very funny but doesn't match my first-hand experience of owning and using a Saniflo for many years. As long as you didn't put anything stupid down it (like wet-wipes), it was trouble free.

Tim

[Stephen]

Boxing in any other pipe work would be unobtrusive, soil pipe would be much bigger but it's the only way, I don't mind doing that. What fall does soil pipe need? The height of the outlet on the toilet isn't that high to start with.

[Stephen]

I never expected that; that might make things easier.

[Tim Watts]

18mm/m - did you not see my earlier answer with links to Part H?

[chris French]

In message , JimK writes

:-) yes, I am hoping it will work ok. I did work it our roughly, and think I can get about 30mm/m fall on the pipe. Which should be ok.

[chris French]

yes, I forgot about running below the ceiling, (silly , as I had to do that with my shower waste pipe recently - kind of annoying as it was only about 1.5m of pipe. but straight through the wall at just where the pipes would go are four cables for the mains supply (old 3 phase supply)

[Stephen]

Thanks. I think I posted that question in reply to another poster before I had read your reply. Next time I will read all new posts before replying to any. 18mm/m is much less than I was expecting: I was expecting much steeper angles, so it might be do-able after all.

Thanks again, Stephen.

[Tim Watts]

18mm/m is actually steeper than you think when it comes to water flow.

As I mentioned, if it were just bath water, you can use less (I think mine is more like 10mm/m - BUT I would not use such a shallow run for a toilet pipe and I'd be dubious using it for a basin or kitchen sink as you get a lot of solid matter (toothpaste blobs, richards and food) which can easily settle out in the middle and start an obstruction.

Because my soil pipe comes up through a solid ground floor, I could not connect the bath to it (too low, major risk of back-flush) so I took that "the long way" through the house to a grey-water-only 110mm drain that serves the kitchen and a rear shower. The basin and the loo went direct to the local foul pipe.

[Hugo Nebula]

Is the ground floor a timber-joisted floor with a void below? If so, install an internal soil stack to the first floor to a new branch under the ground floor. Take it either directly to a new inspection chamber on the existing drain to the rear, or onto a new connection onto the existing soil stack. The new stack will need to be ventilated; either an open vent 900mm above the uppermost windows, or an air-admittance (a.k.a., a "Durgo") valve.

If its not a joisted floor, the above could still be done but it would involve digging up the ground floor slab.