Kinked wet vertical soil pipe

[buffster]

Hi

I'm planning the refurbishment of my house, and I'm looking to add an ensuite bathroom to an attic bedroom. The soil pipe would need to pass to the right of a couple of floor joists, but in an ideal world I'd like to then kink it to create a bit more space on the floor below. There's nothing I can do with the floor joists. I know it's not best practice to do this, and, given that I'm only doing it to create space, would this be acceptable or would a building inspector insist the entry at ground level was moved towards the wall to allow a vertical pipe?

Many thanks in advance.

 

[Hugh Jaleak]

Not ideal, but cannot see BCO making an issue of it. Regs do say bends in the wet section should be avoided where possible, you cant avoid them here so they have to be used.

Main issue would be with noise from falling waste, if pipe is to be boxed in, use fibreglass insulation to help with sound deadening.

 

[buffster]

Cheers for that . I hoped it would be OK, but given that the only reason for wanting to kink the pipe is to have more room on the ground floor I wasn't sure if that would be deemed too frivolous.

2 further quick questions if I'm not pushing my luck. I take your point on noise, and yes, I would certainly insulate for sound; in fact, just for this stack I was seriously considering using one of the noise reducing soil pipe systems. However, my understanding is that the internal diameter is smaller; would that be likely to significantly increase the possibility of a blockage in an already less than ideal configuration?

Secondly, I only need to offset the pipe by about 100mm, would using 30 degree or even 15 degree elbows be better than my originally suggested 45/135 degree ones?

Btw, I should have included in the drawing that I intend to have an access point just above the kink, I assume this would be a good or even required idea.

 

[Hugh Jaleak]

The slower the bends, the better, if you can do it with 15° bends, go for it. Not come across noise reducing systems, but 110mm pipework wont be an issue if installed correctly. If using slow bends, falling waste wont have much to bounce off anyway until it gets to the bottom.

Is the drain run accessible from a manhole outside? Stacks rarely block in my experience, and opening an access point on a backed up stack, inside the house would not be my idea of fun. They are only usually needed as a last resort if not other access to the drain is available.

 

[buffster]

The drain run would be accessible from an inspection chamber, and yes, using the access point inside would 100% be a last resort, but I thought it would be an idea just in case my kinky idea caused any problems, either at the kink itself (maybe unlikely) or, should the the kink cause any degree of solid/liquid separation, at or after the rest bend at the bottom which is more of a concern.

Many thanks again for your input.

 

[Hugh Jaleak]

If you can rod/jet the line from the manhole, that'll be good enough. I've only known a Stack block once in nearly 40 years, and that was a regular culprit, same property, Housing Association were happy to keep paying for it to be unblocking, rather than replace the stack.

 

[buffster]

Cheers