Soil pipe woes

27 Nov 2009
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United Kingdom
I have a challenge regarding a bathroom refit! Not sure if this is a plumbing or carpentry prob. Here goes...

The top of my current (11cm diameter) soil pipe runs parallel and between the floor joists. It's top is 6cm below the top of the floor joists. A branch then a 92.5 degree bend brings it above the floor so this branch can run above the floor, perpendicular to the joists, along a wall. This is boxed in. Toilet and sink both feed into this.

It's a smallish bathroom, and I want to instal a wet room floor directly over where the soil pipe rises through the floor. Trouble is, wet room floor would be too high (by about 5cm) so I'd not be able to get under the shower (ceiling is low and angled as it's just below the roof). I'd really like some advice on these options:

1. Try to see if using solvent weld (instead of push fit) and cutting back the straight part of the bend gives me a few extra cm.

2. Notch the 22cm x 5cm joist beside the pipe (by about 10cm), swivel the pipe where it branches by 45 degrees and attach a 45 degree bend. Reinforce the joist with a 1 x 10 x 40cm steel plate bolted through the joist. This will be almost in the middle of the joist's 4m span.

3. Just let shorter people use the shower. :cry:

4. Instal a velux window above and to the side of the shower and stick my head out of it when I use the shower. ;)
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if this isint your main bathroom you could install a macerator, the 4" pipe could be reduced to inch and a quarter and probably tucked under the floor, depending on how big the joists are.
option 1 :idea: you might be able to get a "knuckle" bend in 110mm soil
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Sorry for my ignorance, but what is a "knuckle" bend? Does it just mean it goes through 90 degrees in a short distance?

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