How can I seal a soil stack entering a flat roof?

[xpeterpx]

At the moment I've made up a temp fix acting as a sort of collar around the soil pipe at the point where it enters my flat felt roof extension.
The area around this point leaks and I need to get it sealed.

I've looked into getting a pipe collar placed around the pipe and torched on but I think the pipe is too near the wall for it.

At the moment the existing covering is only cement which has cracked from the movement of the pipe and has created gaps.

Any ideas on how best to seal aroung this pipe?

thanks as usual
Pete

 

[xpeterpx]

sorry double post

 

[noseall]

What material is the SVP? Plastic, iron, asbestos?

How far above the flat roof does it extend?

I would buy a (non-pitched) lead multi-slate, cut the appropriate hole out of the rubber, slide the thing on with some silicone spray to help, and turn the one side up the wall whilst dressing the remainder flat onto the roof.

I would then have a flat roofer come and fix his flashings around the lead slate.

It will all depend upon being able to access the SVP in some way.

 

[s60tsy]

is it holding water around the pipe? if so you have your first objective