Which soil stack components to order?

[ruggers]

I need some advice of some components to order for my external 110mm svp where it leaves the 1st floor bathroom on a masonry build.

 

I'll have 2no. vertical lengths of svp with a 67.5° branch in the middle.

 

The 117mm bathroom toilet core hole will have a 110mm plain pipe between inside and outside and then it will require an elbow, followed by 600mm horizontal section connecting the elbow to the svp branch.

 

1. Should the elbow be 87.5 or 92.5 and should it be single or double socketed?

 

2. I'm assuming one socketed end goes against the core hole to receive the pipe through the wall. If correct do you need to chase the external brick out some more so that the wider outside diameter of the socket end can be positioned part in to the wall and prevent it from sticking out away from the wall too much more than the bracket offset?

 

3. The horizontal pipe connecting the wall elbow to the branch will require plain pipe or a socketed end depending on single or double socket elbow. I wasn't sure if double socket is fine or its best to keep everything designed like a funnel by using the cut off socketed end from the 4m vertical svp if this makes sense?

[Nickfromwales]

On 10/07/2026 at 18:21, ruggers said:

I need some advice of some components to order for my external 110mm svp where it leaves the 1st floor bathroom on a masonry build.

 

I'll have 2no. vertical lengths of svp with a 67.5° branch in the middle.

 

The 117mm bathroom toilet core hole will have a 110mm plain pipe between inside and outside and then it will require an elbow, followed by 600mm horizontal section connecting the elbow to the svp branch.

 

1. Should the elbow be 87.5 or 92.5 and should it be single or double socketed?

 

2. I'm assuming one socketed end goes against the core hole to receive the pipe through the wall. If correct do you need to chase the external brick out some more so that the wider outside diameter of the socket end can be positioned part in to the wall and prevent it from sticking out away from the wall too much more than the bracket offset?

 

3. The horizontal pipe connecting the wall elbow to the branch will require plain pipe or a socketed end depending on single or double socket elbow. I wasn't sure if double socket is fine or its best to keep everything designed like a funnel by using the cut off socketed end from the 4m vertical svp if this makes sense?

Better late than never lol!

 

1. Either is fine, but typically a 92.5 is obtuse so the better choice for a smooth fall; the socket gives the extra bit of wiggle room if you need to increase the fall slightly.

 

2. The socket has to go into the wall, or the stack is way too far off the wall. I core out at 117, and then just chip away gingerly until the knuckle of the fitting will find its forever home. Sand and cement mix to patch back in, foam for the internal gap.

 

3. OCD is the killer here, and I'll always try and have flow going into a socket, from a spigot, but in actuality it doesn't matter a single jot, so just do whatever is easiest or what is convenient on materials on site. The golden rule is to cut the pipe square, and chamfer properly, silicone lube both before mating, and life will be wonderful for a very long time. 

[ruggers]

Thanks Nick. I've installed before but many years ago and when using white components they were cheap and in abundance at most places plus a I was rendering the outside then.

Anthracite grey in 110mm pipe and some fittings is bizarrely harder to get hold of. 

I've just had to correct the received quote this evening after they buggered it up somehow from a nice easy list.
Couldn't get 4m lengths in this shade which the longer socketed end of a 4m would have been great to keep funnel type design so one will need to use a double socket 92.5 bend but it's in a less viewable elevation. 

 

Branches have 67.5 and 92.5. The 92.5 looked to be recommended for more of a horizontal run to the stack.