As a very amateur plumber, I sometimes find I assemble pipework but then have to disassemble it, eg to pop a fitting over the other end of the pipe, or to adjust the alignment. Push fit allows me to get away with that, and bendy plastic pipe requires less accuracy anyway.

The skill that pro plumbers have with copper pipe is partly the solder joints, but more importantly "getting everything right first time" as it is very difficult to disassemble if something turns out 3mm too long.

"Bathroom company" fitters seem to use pushfit plastic.

I actually find the waste pipes are the most difficult.

We used plastic plumbing for all the long runs, so there are no joints hidden away. The plumber I used put short copper tails on the plastic just before we attached the flexible tails of the taps. There's also copper at the start of the plumbing, where's there's a kind of home-made manifold of isolation valves at the head end of all the long runs. Wastes are plastic everywhere, starting with push-fit and transitioning to solvent weld for the more serious stuff.

Posted By: Jeff Balways, always put in lots of service valves which plumbers seem very reluctant to do

I get the impression that omitting isolation valves is yet another British disease, but maybe I'm too kind to our continental neighbours? But anyway, they're definitely a good idea.

I agree about the usefulness of service valves, but have reservations about the kind that have a little rotating ball turned with a screwdriver. In my (bitter) experience they are liable to leak the first time you use one because the exposed surface of the ball has tarnished in the meantime and damages the seal when turned.
Also they do impose a restriction in the flow, which may not matter but can make them noisy as water whistles through.

The best I think are proper gate valves, but they are obviously a bit unsightly.

I like plastic pipes and fittings

If there’s a chance of mice/rats/squirrels then copper, if not then plastic is so much easier. Isolation valves are handy but the “ballofix” type will likely leak when used 5 years later. Proper lever valves at suitable locations ( to isolate chunks of the system rather than every tap etc) you can soon cap a connection if you need to go and get a fitting etc.

Posted By: philedgeFor service valves always buy branded ones as youve got more chance of them not leaking a decade after install when you come to use them.

+1. However a good idea to turn them each year to keep them usable.

Posted By: revorI use both, plastic to run pipes through awkward areas and to avoid joints underfloor or in partitions etc. I like to have easy access to every joint. For pipe runs involving heating systems to and from cylinders boiler etc I prefer copper solder joints less bulky than compression fittings.

More-or-less what I do too.

Posted By: djhThe plumber I used put short copper tails on the plastic just before we attached the flexible tails of the taps.

Avoid flexible pipes wherever possible, and only use them where you can easily get at them to replace them. They have a limited lifespan and can (and do) burst after 10-20 years.

I'm definitely a plastic advocate, but I will often use the Pegler/Yorkshire Tectite fittings (the pro ones).

I use flexible tails with an integrated valve and push fit.

You can easily just use 10mm to basins and toilets.

If you have a risk of mice, beware. They love plastic pipe!

Stand the pipes off the wall more than the normal clips so you can get thick insulation on. Round the tank etc, again, think of insulation - plumbers leave the bare minimum of a gap often making insulation problematic. I use a double layer of black EPDM insulation so need a bigger gap around each pipe.

I have seen a growing used of crimped copper fittings.

<blockquote><cite>Posted By: Artiglio</cite> Isolation valves are handy but the “ballofix” type will likely leak when used 5 years later. Proper lever valves at suitable locations ( to isolate chunks of the system rather than every tap etc) you can soon cap a connection if you need to go and get a fitting etc.</blockquote>

This has always been my experience - crappy isolation valves that don't actually work and need to be replaced at the same time as the thing you're trying to isolate. Turning off the whole system briefly is little more effort and you can cap a pipe with a push fit end if it needs to stay off for a while

I used central manifolds and plastic everywhere (but none of it is visible). Whenever the manifolds are exposed (they're behind a built in bookcase) I turn them all off and on, but I'm pretty convinced they'll stiffen up to be useless, or leak, by the time I actually need to use them 'in anger'.

Posted By: Peter_in_HungaryWhen we talk of plastic pipes can I assume we are talking plastic and not pex?

PEX is a plastic (cross-linked polyethylene).

We haven't mentioned Supplementary Bonding. Some electricians IMI insist on there being green/yellow electrical connections clamped to anything in the bathroom which is not visibly piped in plastic (eg where a copper tail above floor level, transitions to plastic below the floor, where it cannot be seen by the electrician).

One sparky in particular was very awkward about signing off some completely unrelated work elsewhere in the house, because of the missing green/yellow clamps in the bathroom.

There are exemptions in the wiring regs where supplementary bonding is not required to copper-piped fittings, but some expert interpretation is required and the sparky might find it easier to insist on you bonding everything. It's one of the areas of the wiring regs where sparkies like to disagree.

If you plumb in plastic then the issue doesn't arrise. Worth avoiding a mix of plastic and copper I think.

Yep, the issue for the sparky I mentioned was that he could only see copper pipework tails in the bathroom without any supplementary bonding, and copper pipe near the mains water supply without main bonding. I knew it was all plastic pipe below the floor and the blue plastic supply wasn't extraneous-conductive, but that wasn't visible to him without ripping up the floor, so he assumed the worst case.

If doing another bathroom or kitchen, I'd bring the plastic pipe above floor level to avoid causing anyone doubts.

Posted By: Simon StillPosted By: Artiglio Isolation valves are handy but the “ballofix” type will likely leak when used 5 years later. Proper lever valves at suitable locations ( to isolate chunks of the system rather than every tap etc) you can soon cap a connection if you need to go and get a fitting etc.

This has always been my experience - crappy isolation valves that don't actually work and need to be replaced at the same time as the thing you're trying to isolate. Turning off the whole system briefly is little more effort and you can cap a pipe with a push fit end if it needs to stay off for a while

So exactly that happened tonight, after a leak in the washing machine. The isolation ballvalve was jammed and useless. But the house mains stop valve was only six feet further away, and I know it works because I use it whenever we go away. It was so little effort to turn off the house supply, disconnect and cap the washing machine feed, that I'm not going to bother trying to remove the seized isolation valve to replace it.

I've mostly switched to plastic from copper. And would also echo the comments on cheap ball valves being almost as much of a pain as they are useful, over the long term. Spend some money on decent ones.

The best use of plastic pipe is if you can thread it all without joints. Ideally the modern manifold-style plumbing where you know there are no joints in each run.

To be fair I've not done this (because it's usually only practical in new-build) and just do conventional plumbing with corners and fittings (JG) and have not had any joint failures, but then I've only been in this house for 17 years. My oldest (Hep2O) piping is in the previous house and must be ~29 years old now. I could go round sometime and ask if it's leaked yet :-) It was fine for the 12 years it was installed there. Plastic is just less faff than bending and soldering, and is easy to change around later.