Polypipe/copper pipe laid between PIR insulation in extension area

[scrowlerfly]

Hi folks,

We are in the process of getting a rear extension built with the following sandwich layer:

Finished floor
screed with wet UFH heating
PIR insulation boards
Concrete
DPC layer
Hardcore

We are having a new water pipe (blue poly pipe) laid from the front of the house all the way into the extension where the kitchen will be. The builder is planning to lay the poly pipe between the concrete and PIR insulation board. Is there any reason why he shouldn't do this? It will be a continuous length of pipe with no joins. All the copper work (hot and cold) will be laid on top of the final finished floor level.

It's only the blue poly pipe that he is insisting on laying beneath the final finished floor.

Can anyone see any reason why he shouldn't do this? I've tried reaching out to the building control inspector but he has gone AWOL.

Thanks!

 

[Mr Chibs]

I did mine this way, cold water pipe under the insulation, warm water pipe I routed in the screed with the UFH pipes.

You may need a polythene sheet/dpm on top of your insulation, if you are clipping pipes to the insulation... if you are using castellated trays, you shouldn't need one.

 

[denso13]

Can anyone see any reason why he shouldn't do this?

It is contrary to the water regs as it should be accessible. Below the screed but within a chase in the concrete is ok, but not below the concrete.

Some examples here, https://www.waterregsuk.co.uk/downl...flets/para_7_guidance_version_2_july_2014.pdf

Edit : Just re-read, you seem to mean above the concrete and within the PIR. Could be ok as per the link but if there is UFH in the screed you could still argue the pipe would be inaccessible.