The run from WC to soil stack is going to be tortuous... is 5 90deg elbows over a total horizontal distance of about 3m ridiculous?

This is something that really begs for a picture... perhaps a different perspective from a fresh set of eyes might lead to a better alternative. Because 5 - 90 degree elbows is a blockage waiting to happen.

Total agreement with Smoothy! Simply put, code won't allow this without 2 or 3 cleanouts... never mind that as was stated, it's a blockage waiting to happen.

Post the picture if you can...

Mark

Hopefully a picture is attached... it's a small room with a sloping ceiling and there is a chimney breast right in the way. Being 6'3 I don't want to have to duck to get round things. I can save 3 elbows by turning the WC 90 degrees, but then it's very tight with the basin.

Ok, is there a reason it has to follow the path you mapped in red.

What country are you in... I ask that because at least in the USA and Canada, our Toilets empty from the bottom through the floor and I know many in Europe empty out the back into the wall. Your use of WC (wash Closet instead of Bathroom) tells me you aren't on this side of the pond.

Are these pipes being routed through a wall, or under the floor. Is this a new construction or a remodel of an existing one.

Hi yeah thanks for your help. I'm in the UK. The waste pipe will come out the back of the WC, not down. The joists are too shallow to run the pipe under the floor anyway. It's a very old wooden house (built before 1750). The pipe will go out through the wall just as soon as it gets round the chimney, but to go round it will have to run in the room above the floor (I would box it in to hide it).

My reason for not putting the WC in the obvious place (on the back wall near the existing vertical soil stack) is that there's nowhere else with enough headroom to put the shower.

... I take it you reckon my current proposed layout is hopeless?

Hmmm, that's going to be a tough one. I assume entry to the room is at the bottom of the picture, with the right half being the lowest part of the roof. Do the prroms actual dimensions allow you to move things around like the shower more to where the toilet is now, and allow you to move the toilet to where the shower is.. you are going to be trading one inconvienience for another... having to snake out a clogged waste drain will be very difficult at best... impossible at worst, and I will guess it would be a frequent occurrence.

From my perspective that is significant enough to use as a basis to design around.

As a thought... since you will be sitting when using that appliance, could it be placed on the top wall, and the tub be pushed further down on the drawing to allow leg room? I know it's a rough drawing and not to scale. The shower obviously has to be on the left side of the drawing... but could it be placed where you have the toilet now? If there isn't enough room to just move the tub to the lower corner and have enough room at the top leaving the shower where it is.

My advice would be: Use 2 - 45 degree bends to make each turn with 6" of pipe in between fittings. Furthermore - and by my Code book, you have to have clean out every 135 degrees of turns.

I suggest you run your waste pipe though the floor, directly to the stack or put the toilet in niche between the chimney and the stack ( on the opposite side of the chimney ). 90 degree bends inhibit sewage flow causing frequent back ups. Also, if installed in framed floor on 2nd story house they are noisy, especially at night.

Back to you. Milo

Thanks for the advice everyone. Smoothy, your assumptions are all correct. From what you guys are saying, I'm going to have to come up with a plan B: shower stays where it is, bath comes down a bit and WC goes on the back wall to the right of the shower.

I wanted to avoid it because the WC will be jammed up very close to the shower enclosure and I'll have to duck slightly to get there. However what you are all telling me is I don't have a lot of choice! I will just have to deal with it - the benefit is it will be less work to install.

Thanks for the advice everyone. Smoothy, your assumptions are all correct. From what you guys are saying, I'm going to have to come up with a plan B: shower stays where it is, bath comes down a bit and WC goes on the back wall to the right of the shower.

I wanted to avoid it because the WC will be jammed up very close to the shower enclosure and I'll have to duck slightly to get there. However what you are all telling me is I don't have a lot of choice! I will just have to deal with it - the benefit is it will be less work to install.

Installation is a one time inconvenience... dealing with frequent toilet clogs are going to be a frequent and ongoing inconvenience... I personally consider that to be the major point of consideration. Or as we like to say... the lesser of two evils.