Soil pipe minimum distance from wall.

[epsilonGreedy]

I have found some threads that discuss how to overcome the problem of a soil pipe that emerges from a ground floor slab too far from the wall. I am looking at the opposite problem of being too close  to the wall.

 

My block and beam floor is going in over the next two days and the vertical stack of the ground floor toilet looks a bit tight to the external house wall. I understand that at FFL some sort of boss will be fitted, do these have much of a flange?

 

At this stage there is some flexibility because the vertical drop from FFL to the top of the horizontal drainage pipe is 700mm.

Edited August 13, 2019 by epsilonGreedy

[joe90]

I found different manufacturers of soil pipe toilet connectors have different dimensions , I went through several to find one that fitted properly, the ones I settled on have a rubber flange that covers about 10mm around it. Can’t  remember where I got them from now ?

[Onoff]

Loads of options from a couple of offsets like this:

 

 

To a minimal offset like this:

 

 

[Jeremy Harris]

I ended up having to fit one of the small offsets (like the lower one in the photo above) at the base of our soil stack for the same reason, the pipe came up a bit too tight to the inside of the wall at the rear of the house.  I chipped out a bit of space around the vertical pipe where it came up through the slab and slotted the offset fitting down into it so that the stack then cleared the inside face of the wall OK.  Seems to work fine, it's been in and working for over 5 years now.

[ProDave]

I deliberately set mine as close to the wall as possible.  The builder doing the foundations tried to tell me it was too close.  But I wanted it so the stack pipe was partly enclosed in the service void.  And it worked out just fine.  

 

If it is a bit tight I am sure you can shave a bit off the wall for any flange.

[PeterW]

35 minutes ago, Onoff said:

Loads of options from a couple of offsets like this:

 

 

 

To a minimal offset like this:

 

 

 

That is a clay adapter and not an offset ..! It’s got a ridge in it that will collect crap....

 

@epsilonGreedy the correct gap is 35-40mm so you can get a branch with a boss in there, and you should also have a bracket or two to stop it vibrating when there is a flush dropping down it. 

[Onoff]

22 minutes ago, PeterW said:

 

That is a clay adapter and not an offset ..! It’s got a ridge in it that will collect crap....

 

@epsilonGreedy the correct gap is 35-40mm so you can get a branch with a boss in there, and you should also have a bracket or two to stop it vibrating when there is a flush dropping down it. 

 

Best you contact McAlpine then and tell them they've got it wrong and that it can only be used to go into clay...

 

 

?

[Jeremy Harris]

I went into this in detail when I had the problem, and someone on Ebuild suggested I use the McAlpine offset connector (can't remember who).  I ended up getting advice and was told that the fitting was perfectly OK for use at the base of a vertical soil stack.  TBH, I can't see how anything could get caught inside it, as there is a significant slope on the offset step inside.

[Onoff]

Just now, JSHarris said:

I went into this in detail when I had the problem, and someone on Ebuild suggested I use the McAlpine offset connector (can't remember who).  I ended up getting advice and was told that the fitting was perfectly OK for use at the base of a vertical soil stack.  TBH, I can't see how anything could get caught inside it, as there is a significant slope on the offset step inside.

+1

[PeterW]

Used to be listed as an internal clay and iron adapter (hence the finned seal), not seen one listed as a plastic adapter before so looks like it could work. 

 

I don’t like anything with steps or edges in them but assume it works fine. 

[Onoff]

55 minutes ago, ProDave said:

But I wanted it so the stack pipe was partly enclosed in the service void. 

 

Is that an internal stack?

[epsilonGreedy]

2 hours ago, PeterW said:

 

@epsilonGreedy the correct gap is 35-40mm so you can get a branch with a boss in there

 

 

You just anticipated a question I was due to post in 2034 when we plan to retired the garage utility room and move some white goods into into the rear entrance hall. Would this boss allow a washing machine drain to be clamped onto a soil stack just below or above FFL? The washing machine will be sited just 2ft away on the other side of a medium block partition wall.

[epsilonGreedy]

2 hours ago, PeterW said:

and you should also have a bracket or two to stop it vibrating when there is a flush dropping down it. 

 

 

Ok so a stabilizing bracket is recommended even for the 600mm unsupported drop in the void below the floor block? 

[Hobbiniho]

30 minutes ago, epsilonGreedy said:

 

You just anticipated a question I was due to post in 2034 when we plan to retired the garage utility room and move some white goods into into the rear entrance hall. Would this boss allow a washing machine drain to be clamped onto a soil stack just below or above FFL? The washing machine will be sited just 2ft away on the other side of a medium block partition wall.

 

you only need a small gap ~10mm to get a strap boss in providing you have a straight bit of pipe to connect it onto

[PeterW]

33 minutes ago, epsilonGreedy said:

 

Ok so a stabilizing bracket is recommended even for the 600mm unsupported drop in the void below the floor block? 

 

That should be dropping into a properly haunched rest bend that is encased in concrete so it can’t move.  

[Russell griffiths]

So if your floor is not fitted yet, why not move the pipe into the correct position ?‍♂️

[Oz07]

I usually find pipe wants to be around a inch off finished wall to accept pan connector. @Nickfromwales is there a standard for pan connectors?

[epsilonGreedy]

16 hours ago, Russell griffiths said:

So if your floor is not fitted yet, why not move the pipe into the correct position ?‍♂️

 

 

The drainage pipe work is in position and the major components are concreted in. I hope with a 600mm rise the the stack to FFL the stack pipe can be tweaked away from the wall by an extra 10mm.

[Russell griffiths]

Have your floor beams been designed to accommodate the pipes coming up, may be better to get the beams in and manipulate pipe accordingly. 

[epsilonGreedy]

1 hour ago, Russell griffiths said:

Have your floor beams been designed to accommodate the pipes coming up, may be better to get the beams in and manipulate pipe accordingly. 

 

 

Yes in most cases though one first floor stack might be problematic because of a last minute tactical drainage change of plan. We had to flip the ensuite stack to the other wall in order to prevent one stack dropping directly into a horizontal pipe. It now flows via a bend into a y-piece then the main branch as per the @PeterW  advice in another recent thread.

[Nickfromwales]

On 13/08/2019 at 19:49, Oz07 said:

I usually find pipe wants to be around a inch off finished wall to accept pan connector. @Nickfromwales is there a standard for pan connectors?

I normally bring them up tight to the plasterboard, as you can always find a way to bring the fitting forward, but not so easy to move the pipe set into the floor back...