Insulation and ventilation around stench pipe in bathroom

[Oxbow16]

Hi

 

I’m in the process of insulating my bathroom. I’ve taken the plasterboard down and put PIR between the rafters and joists, with more PIR beneath, perpendicular. We have a cold roof. The bathroom is more skeilings than ceilings. In the rafters, I’ve left a 50mm air gap between the topside of the PIR and the roof felt.

 

In the corner of the room there is a sewage/stench pipe from floor to ceiling and through the roof. I plan to box this in. I’m a bit confused about how best to tackle the stench pipe from a insulation and ventilation point of view... Presumably it will form a thermal bridge?

 

- Should I insulate and seal around where the pipe goes through the ceiling and PIR?
- Can I insulate around the pipe from floor to ceiling inside the boxing?

 

That’s what I had planned to do, but I then got confused as to whether this could cause problems with condensation or anything else on the pipe seeing as part of it is outdoors? The solution doesn’t need to be top notch from an insulation point of view; it’s an old house which will always have compromises. But with the pipe being out of site once boxed in, I want to make sure I get it right and don’t cause any hidden problems.

 

Many thanks

[Oxbow16]

A few things got in the way but now returning to this and wondered if anyone has any thoughts please?  

 

Many thanks

[Nickfromwales]

1 hour ago, Oxbow16 said:

A few things got in the way but now returning to this and wondered if anyone has any thoughts please?  

 

Many thanks

Hi.

Just surround the pipe with acoustic rockwool and box in with plasterboard. Use foam to seal at the floor and ceiling, patching in with plasterboard if the gaps are "major". 

Foam all round a soil pipe really amplifies the sound, as I did one that went down through a B&B lobby once and it was noisier than with just a boxing around it. Got swapped out for rockwool.

[Oxbow16]

Thanks for the advice (and sorry I forgot to come back sooner to thank you!  I forgot all about it...).  Space is a bit tight between the toilet and boxing, but I got in as much as I could.  

 

Cheers