Vermiculite insulation

[Mchoa]

Alright lads,

Working on a domestic project bringing heating flow/return, hws flow/return, boosted cold and mains cold in a trench from an external plantroom through the basement to the riser.

Its been suggested for the pipes to be insulated with foil faced phenolic foam and then covered over with vermiculite in the trench before a cover plate and floor finishes. Does this sound like a suitable solution and will the vermiculite add anything to the insulation. I've heard it will help stop the hot pipes heating the mains and boosted cold.

Thanks in advance

 

[gmartine]

It'll certainly add something, not sure it'll add too much over and above the foam lagging but it's cheap, non-toxic and easy to install and if the client is happy to pay for it...

 

[ShaunCorbs]

armaflex all the way

 

[Best]

Vermiculite is a nuisance to work around later and maybe over the top for that job.
I would just use heavy Armaflex or whatever, and ideally keep cold and hot pipes in separate voids.
Vermiculite if it gets wet will absorb masses of water, so be aware of that.

 

[jonnyswamp]

Uponor pre-insulated pipe is excellent, but very expensive
I used it on a barn conversion where the boiler was around 20 m away from cylinder room
I think it came to around £1600 for 2 x 25m lengths of twin pipe

EDIT, actually I think it was £1600 each length