Radiator supply pipes

[Tristar]

Hi guys, my conservatory floor is constructed with a cold slab, so the 15mm feed and return pipes will run above the vapour membrane which lays on the Celotex insulation and be covered by 75mm screed.

My questions are:

Is the yellow coated copper pipe the correct type for use here, allowing sufficient expansion without cracking the screed?

If not, could plain copper pipes be coated in the split foam type pipe insulation used on pipes above ground? And possibly sunk slightly into the Celotex and underneath the membrane.

 

[kevplumb]

just a suggestion why not use plastic in one long lengh

ie no buried joints

you can always use copper where it shows

 

[Tristar]

Hiya Kev,long time no speak.

Just old fashioned I guess, but I still prefer to use soldered fittings. Did I not read somewhere that poly joints were a bit dodgy in screed?

 

[Tristar]

There are two radiators in the conservatory, which is 6m x 4m, (see pix on building forum) and the pipes have to run around the outside of underfloor electric heating. Anyway there would have to be joints to come up to the rads.

Is the yellow insulated pipe OK for this situation?

 

[kevplumb]

i would think so as long as you get the stuff with the air gap in the sheathing

 

[Tristar]

i would think so as long as you get the stuff with the air gap in the sheathing

Thanks Kev, I hadn't realised that there were with & without air gap types.

View media item 358 The pipes will run from the top corner by the house to the first rad on the straight wall, and then all the way around the hexagon and then to the second rad to the left.

 

[kevplumb]

sheathed with air gap

 

[Agile]

The sheathed type is designed for use with gas ( although not liked by CORGI ) but its very expensive!

I would use the standard split foam myself as it gives good insulation and allows expansion. I would have no quarms about using soldered copper fittings in that.

However much as I dislike plastic, the advantage of having no fittings within the slab is considerable.

Plastic should not be burried bare within concrete but most builders do just that with few problems as far as I am aware.

I think that there is a thin convoluted plastic tube sold for the purpose, very similar to the flexible waste used on WMCs. That might be more easily available in the WMC form too.

Tony

 

[kevplumb]

The sheathed type is designed for use with gas

tosh as usual

read the link

 

[Tristar]

Thanks Kev, I'll try to get hold of some of that.

 

[Tristar]

I believe that you can get pipe benders for the plastic coated pipe, will they bend the Kuterlex Plus also?

 

[kevplumb]

yes might need oversize formers though

 

[Tristar]

yes might need oversize formers though

Thanks, I expect if hire shops have them they will have the bigger formers also.