Expanding foam on copper heating pipes

[tommy8884]

Morning. I just had my single pipe system replaced with all new pipes and rads. We have 4x chases to deal with on external walls. 2 drops from upstairs and 2 across walls to rad locations. The chases are not deep enough to put pipe lagging on the pipes. I know i need some protection before rendering the chases. I could just put gaffer tape on the copper, but would need a lot of filling material, i would lose heat, and I'm worried about the heat affecting the plaster.

Could i "lag" the pipes with expanding foam first, such as this one?

https://www.screwfix.com/p/soudal-gap-filling-foam-hand-held-750ml/46137

It says it can be used on pipes and it says it is good for insulating and is resistant up to 90c. What is doesn't say is, is it ok for copper pipes? I've read that expanding foam can be corrosive for copper pipes.

Any advice would be appreciated.

 

[RandomGrinch]

If you're worried about the foam, have you got space to wrap this stuff around?
https://www.screwfix.com/p/spiral-wrap-x-50mm-x-7-5m/62194
Or traditional Hessian wrap?
You could foam around the covering afterwards.
I've used rockwool to pack out and stuff holes, but probably not suitable for your use.

 

[tommy8884]

If you're worried about the foam, have you got space to wrap this stuff around?
https://www.screwfix.com/p/spiral-wrap-x-50mm-x-7-5m/62194
Or traditional Hessian wrap?
You could foam around the covering afterwards.
I've used rockwool to pack out and stuff holes, but probably not suitable for your use.

That looks ideal. And cheap. Thank you

 

[iateyoubutler]

Aren`t hot water cylinders covered in the stuff? Surely that should answer the same question