Hot water pipe underground

[pilsbury]

As part of my kitchen extension, I'll be having an island with the sink in it. I'm at the groundworks stage. I've already done the drainage for it and need to run pipework for hot and cold feeds. My drainage trenches luckily run from the garage (where I can easily get hot and cold feeds from the boiler) to where the island will be.

What's the done thing to do with the hot water pipe when burying? Insulate? How? Will much heat be lost uninsulated on a 6m run? What about cold feed? Depth will be approx 750mm

 

[PrenticeBoyofDerry]

Hot and cold water will require the same thoughts of route.
Is the pipework to be routed outside the thermal envelope?

 

[Nige F]

6m of hot pipe (15mm) is a lot of wasted water every time you draw hot. Consider a small unvented hot store in the island or a boiling water tap e.g Quooker taps.

 

[Agile]

Since pipe insulation is so cheap then I would question why anyone would ever consider leaving it not insulated.

Tony

 

[bernardgreen]

Insulated flexibles in separate ducts for hot and cold. Avoids having to dig out the floor if pipe work has to be replaced / repaired / altered some time in the future, ( though maybe flexibles are more likely to need replacing sooner than copper would )

Two other ducts, one for for mains electric power and the second for extra low voltage cables that may be needed in the future.

 

[pilsbury]

Hot and cold water will require the same thoughts of route.
Is the pipework to be routed outside the thermal envelope?

I had to google "thermal envelope" - yes, pipes will be underground - below insulation and slab.

 

[pilsbury]

6m of hot pipe (15mm) is a lot of wasted water every time you draw hot. Consider a small unvented hot store in the island or a boiling water tap e.g Quooker taps.

Seems a bit overkill for waiting 10 seconds for hot water - those boiling water taps are £700!

 

[PrenticeBoyofDerry]

If it outside the thermal envelope, it will require either insulting or at a depth outside any potential frost zones.
If copper or metallic pipe is installed, it will need to be protected from corrosion.

 

[pilsbury]

The water pipes will be approx 750mm deep. I assume that's outside frost zone as that is what mains pipe needs to be at. I will be insulating, certainly hot so water does not cool over the 6m run, maybe cold....

Will be plastic polypipe