Relocating Soil Pipe Venting

[DazJWood]

I am in the process of redoing my bathroom.

I spent last weekend pulling down a stud wall that originally seperated the bathroom from the toilet. This now gives me a larger area to work from.

I planned out the new room on my pc taking into account the size of the new shower cubicle / steam room / bath type thing that I want (which I have since ordered). With all my measurements right I thought I had accounted for everything and had my new bathroom designed how I wanted.

Unfortunately I forgot to take into account the soil pipe which runs near enough between the original two rooms. This now prevents me from haivng my sink where I wanted it. With the new cubicle thingy ordered I have very few options. Ideally I want to move the soil pipe.

I was thinking of two options:

1) Take the soil pipe, just above where the WC meets it, and drill through the wall and take it outside and up the exterior wall to vent just above the roof.

2) Remove the soil pipe, fit an elbow and take it to the WC as normal, fit using a T piece, then take the soil pipe along to the side wall and up and back into the loft, where I'd have to reconnect back to the original exit in the roof. The problem being that at the side of the wall there is not enough room, (due to a window) for a full sized 110 pipe. I have read that the vented part of a soil pipe can be reduced, with a recommended 75 mm pipe. Ideally 68mm would be better to allow me to box it in.

Are these options feasible, daft or against building regulations?

I'll admit that I am not in any way a vastly experienced DIYer and have not messed with plumbing like this before, but I am keen to have a go and sort it.

Incidentally, I have also read conflicting views about fitting an air admittance valve to a soil pipe and removing the vented part completely. I've concluded that this is not an option. Hmm but I may be wrong!

I'd appreciate some advice.

Thanks in advance,

Daz

 

[Bahco]

I would go with number 1 but would ask building Control if the venting would be affected with it not being a vertical run.

Post back and let us know what they say.

 

[DazJWood]

Ok Thanks for the reply!

Just out of interest, what difference does it make if it's not vertical?

 

[Bahco]

Ok Thanks for the reply!

Just out of interest, what difference does it make if it's not vertical?

Maybe less chance of getting blocked by a nest etc for a guess.

BCO will give you a definitive answer though.

 

[Richard C]

Of the choices I would also go with number 1; Building Regs dictate many aspects of what you can & can’t do regarding offsets in the wet portion of a stack, stack connections, & max lengths of unvented pipe runs but to avoid making mistakes, have a look here, it will tell you what you need to do to comply:
http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADH_2002.pdf

There are also several other useful manufacturer’s design guides; Google Hunter, Marley etc.

 

[DazJWood]

Hey thanks for the reply. I've been looking for that building regs documentation.

Looks like I can reduce the pipe to 75mm.

But doesn't seem to say whether it's ok to move the pipe outside or whether it's ok to reroute the pipe.

 

[Richard C]

Forget the specified 75mm in Part H; it’s a minimum size & the nearest equivalent manufactured size is 82mm as far as I know but I've never seen it used in the UK & I can’t remember ever seeing it stocked; only ever seen 110mm. I’m not sure which of your proposed solutions you are planning to adopt or what you mean by "moving the pipe outside"; if your refering to the top, ventillated portion of the stack, then yes, that's perfectly feasible but if it's at the front of the house, I would ring your local BC first & check is OK. But, for all practical purposes I would forget about putting an offset in the wet portion of the soil stack; i.e. the bit where the hurds go.

If your still unsure, post some pics/drawings to make it easier to understand what you propose.

 

[DazJWood]

I hope I've done this right but I have attached a few of pictures to try and make it clearer.

Excuse the crudity of the drawing.

Option 1

Taking the soil pipe outside and up the exterior wall

Untitled

• DazJWood
• 23 Feb 2009
• 2

Option 2

Rerouting the soil pipe vent across to the side wall and up into the loft to reconnect back to original exit in the roof. According to building regs it seems I could reduce the venting portion of the pipe to 75mm.

Untitled

• DazJWood
• 23 Feb 2009
• 1

Also another view of the area:

Untitled

• DazJWood
• 23 Feb 2009
• 1

Thanks in advance for your opinions and advice,

Daz

 

[DazJWood]

Anyone any advice on what I can or can't do??

 

[Richard C]

The vent should really be on the vertical part of the stack so I would go with option 1 but it’s not exactly elegant; check the BR’s with regard to location of the outside termination of the stack & any windows. Do you have another open stack on the system? If so you could cap off & terminate inside with an AAV but it must terminate above the highest overflow so you will still be left with a stub stack in the centre of the room.

 

[DazJWood]

Thanks for the reply.

No I have no other open stack so can't fit an AAV.

I've read the Building regs and even emailed building control who replied back:

"I am sorry but we are unable to answer your querie as we can only comment on work not covered in the Building Regulations.The only advise I can offer is as long as you keep the vent open if it is terminating outside,or fit an air admittance valve if it terminates in a roof space."

Hmm not particularly helpful and I thought the whole idea of their department was to know things like this! It does not mention anything in the building regulations about rerouting a vent pipe. It does mention about the height of the end of the pipe from windows and loft space etc... But I am ok with that aspect as option 1 would just mean I would take the pipe up the side of the house to the height it is currently. Option 2 would reconnect to the exisitng exit anyways.

I am a little surprised that the reply suggests fitting an air admittance valve in the roof space though as seeing as it's the only soil pipe that doesn't quite sound right to me. Anyways, tis not something that helps me.

So by that answer I asume I could use either option.

Has anyone else done anything similar?

Thanks,

Daz

 

[Richard C]

I am a little surprised that the reply suggests fitting an air admittance valve in the roof space though as seeing as it's the only soil pipe that doesn't quite sound right to me.

I've no idea who sent the reply but if they haven’t asked if your foul drain is vented somewhere else they are not considering the whole picture or maybe it was the tea boy who doesn’t really understand the regs; I would be careful with that one; but go back & ask again telling them it’s the only vent & ask them to confirm you can fit an AAV; if they say yes, who the hell am I to ague with that! But it doesn’t have to be in the loft space either, as long as it’s higher than the highest overflow on that branch; for obvious reasons!

 

[DazJWood]

An AAV is not an option as I previously said because its the only stack vent and the highest overflow would be the sink so defeats the object if it's the sink I'm trying to accomodate in the place of the soil pipe!

Just wanna know feasibility of rerouting and if anyone has done similar. I thought this would have been a fairly common problem but I've posted on a couple of forums and know one seems to have been able to give a definite answer. Lol and with the reply back from Building Control it seems even the professional body don't know!

Nevertheless thanks for your replies! It's an interesting learning curve trying to sort a bathroom out with no previous plumbing experience Might have it done by the end of the year