Plumbing with copper is no mystery me - whole house re-plumb + CH in the last 30 years, but I've no experience with plastic.
I'm wanting to run a new garden water supply and want to know if I can use plastic pipe for it. The single story house layout is such that I would be tapping off from the supply to the cold water storage tank in the attic.
Yes, no problem. For outdoor/underground use, you need blue MDPE pipe - whose OD is not the same as copper pipe. You can get special push-fit type fittings for joining MDPE to copper. If you've got a copy of Screwfix catalogue #115, have a look at page 473.
Did you want to use plastic pipe all the way from the attic? I don't see any real reason why you shouldn't use MDPE inside *and* outside - but others may disagree! As an alternative, you could use Hep2O or PE-X pipe inside (both of which *are* the same size as copper) and join up to MDPE for the outside part. Don't forget to cut all plastic pipe cleanly (*not* with a hacksaw!!) and to use appropriate inserts in all places where a cut end goes into a fitting.
On Wednesday 16 October 2013 22:26 robgraham wrote in uk.d-i-y:
For indoor work (and "just outside") JG Speedfit is a fairly solid system.
The push fit couplers will mate with 15mm clean copper (brown copper is fine, painted is not).
Copper and JG plastic work very nicely together.
One caveat - if you are breaking into a main cold pipe, you may wish to bridge the joint with an earthing strap to ensure earth contunuity to avoid unnecessary weirdnesses or unsafe situations devloping elsewhere.
If the run were majorly outside - like along a fence or under the ground, you'd want to switch to blue MDPE for that part.
Screwfix, Toolstation and even B&Q are a source for JG Speedfit.
You do not need to buy the 15mm JG pipe on a massive roll - they sell it in
Define "garden water supply". Is this just a tap the other side of the external wall from the pipe you wish to connect into or a feed to a shed/greenhouse the other side of a 2 acre garden?
Plastic can be used for either. Just to go through the wall Speedfit/Hep2o would be fine but for much more outside I think I'd use the blue stuff, buried or not. It's far tougher than the normal SpeedFit/Hep2O plastic pipe. If buried preferably >750 mm deep to avoid freezing. If you aren't bothered about it freezing it can be shallower if not under an area where vehicles pass/park.
Plastic pipe is cheap but the fittings relatively expensive, especially when compared to end fed copper. If you only need a foor or two of pipe I wonder if you could blag an off cut from a local plumber or do a bit of skip diving.
Many thanks to you all. Scenario is long thin stone cottage with south sid e garden well developed and supplied with two garden taps and protected mai ns socket. The north side has nothing and is about to get a polytunnel and be turned into the main vegetable plot.
Trouble is that the walls are 3 ft thick and although I have drilled throug h in the past, that's not practical now so I'm going to run from the header tank mains feed to the wall head and then drop down to ground level. Suit able isolation, drain points, etc are planned. As the drop-down will be in some sort of protective duct, I'll use 'white' pipe to a garden tap on the external wall and then 'blue' for the 10m underground run to the water poi nt in the polytunnel.
Make sure you put an isolation valve near where it 'tees off' so if pipe freezes and bursts outside, you can at least isolate it. You should also fit a one way valve (can get bib taps with these built in) to prevent reverse siphonage .... highly unlikely in your case, but water bylaws require it.
You need to cover with pipe insulation ... whether you put it in duct is up to you.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.