insulating pipes

Sounds okay - need to accurately mitre the elbows - stand the pipes off the wall enough to fit the foam Also consider boxing in and filling with polystyrene or Rockwool. What is the length of pipe?

In article , John writes

I've used extra thick pipe insulation on the pipes in my very draughty underfloor, 15mm pipe with 25mm thick insulation. I have other areas insulated with fibreglass and I don't think it is as good for pipe insulation due to the risk of voids and through draughts. For a short straight length I would consider boxing and filling with squirty foam. Using plastic pipe would be a sensible precaution.

Plastic was a no no according to the plumber who is going to commission my combi once I'm done. The length is the full height of the garage, like I say, drop from ceiling to floor (almost)

Ta for tips.

In article , Vass writes

Plastic barrier pipe is fine for c/h as long as it's not within 2m of the boiler (as a general rule). Without hearing the specific reason for the objection then it's difficult to say more (except that he's wrong ;-).

If you use proper 25mm thick insulation, mitre the corners, cable tie every 200mm to make sure the slit doesn't open then tape the slit & joins with duct tape, I'd be happy. It will still be the first place to freeze but if you don't leave the prop unoccupied for extended periods and aren't a miser with the heating in winter then no bother.

I agree. I have seen lots of insulated pipework in garages that gives no problems.

The pipework is mostly vertical, which is less likely to freeze due to internal convection IIRC.

Squirty foam is hygroscopic enough to not be the best foam, nor is the usual grey insulation, use 25mm wall black closed-cell foamed rubber insulation - Armaflex is one brand, probably others. Note it does not like UV so do not use where light can directly hit it (like butyl cables I guess).

There is a Celotex pipe insulation which is thick wall (or even thicker wall, 9mm 25mm 38mm or more available). That should outperform somewhat, I think I stumbled over it on Ebay a year ago.

Why are you suggesting closed cell insulation for a hot pipe? It's used to prevent water ingress for chilled pipework, which isn't relevant here.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Vass" saying something like:

Two layers of ordinary if you can't get the thick stuff. Find the next size up that fits over the smaller size.

Just an additional thought. If you are really worried about the pipes freezing then a pipe stat on the return pipework could be used as a frost stat.