Plumbing - copper vs. plastic

[David WE Roberts]

One of the plumbers quoting for our refurb has suggested retaining the existing copper because of the high price of copper pipe ATM. I am considering this, but suspect that the current central heating may not be laid out in the best possible manner and the hot/cold water system is not good because of long pipe runs and cold water pipes touching hot water pipes so we get hot out of the cold taps for a bit.

So ideally I would like to replace it all and start from scratch.

Which brings me to several options, as usual.

(1) Do it all in plastic and swing in the old copper for scrap to offset a bit of the cost. (2) Do it all in new copper and swing in the old copper for scrap to offset a bit of the cost. (3) Mix old and new copper in an unknown (ATM) ratio. (4) Mix old copper and new plastic in an unknown (ATM) ratio.

So - firstly said plumber didn't favour plastic because he considered the push fit joints liable to fail after 10 years (but again he suggested a magnetic water scale molecule straightener so not 100% informed). Any good reaon apart from plumber traditional predjudice not to use plastic? Plastic pipe and compression joints?

Secondly, and more importantly, how much copper pipe would be needed to replumb your average 3 bedroom semi? [Psychics to supply own chrystal balls.] Screwfix is showing 30m of 15mm pipe (3m * 10) at £77.90 so 60m of 15mm would be £160 which isn't a great deal compared with labour and the cost of new radiators. Waving a tape measure about I would think that 90m of 15mm and 30m of 20mm might do most of it but I could be way out. That would be (£80 * 3) + £150 = £390 so it is starting to add up. [Then again we had some dodgy copper in our last house which pinholed out so there is an argument for all new.]

30mm of 15mm flotex plastic is £24.50 and 30m of 22mm flotex £46.90 so plastic pipe is about 1/3 of copper pipe but you then have to pay for the fittings which are a lot more expensive than capilliary copper. Then again push fit is a lot quicker than even the fastes plumber soldering so there is a potential saving on labour costs.

So - what does the team think?

TIA

Dave R

[Dave Plowman (News)]

Unless you intend DIYing it, accept what your pro wants to do. Telling him he must use *your* choice of materials is an excellent 'get out' clause for him if anything goes wrong.

If you want to have plastic used, find another plumber who prefers this.

[Grimly Curmudgeon]

None at all. Save guarding against rodent chewing, but it's rare the buggers actually chew the pipes.

It's what I've always done, and in hundreds of joints never had a failure.

[David WE Roberts]

Plumber has said he will do plastic if we want. More interested in views as to the long term viability of plastic, and if plastic push fit vs. compression joint.

[David WE Roberts]

*Top post alert* Just to note that I would do it myself but I am employing a builder to do the main construction work and my slow, steady, bugger it the sun's shining it'll keep a couple of days method of plumbing will probably not fit in with his planned timescales and any delay will come directly out of my pocket. Plus I have to have a gas fitter anyway to extend the main and fit the combi and hob.

[Rick Hughes]

I built a new build and used copper from Boiler to Thermal store, Plastic everywhere else. It is so much easier running it like cable ... means far less joints ... so far fewer points of potential failure.

[David WE Roberts]

Thanks - I assume you got a reel of plastic pipe and not lengths?

[Phil L]

Can only say that plastic, especially the joints, look revolting on the surface, so any parts that are to be along skirtings or otherwise on show, really need to be copper. The fittings are huge and stand out like a sore thumb, also the runs of plain pipe never seem to be straight - they always try to go back to being coiled up, so if the rats / mice etc are going to be a problem where the plastic's not on show, you might wnt to look at a mixture of old and new copper for both asthetic and economical reasons. Copper only usually pinholes if it is attacked by verdigris, which usually forms in damp conditions or under concrete if it's not wrapped properly

[Phil L]

a 50m roll of 15mm is about 55 quid, and 22mm X 50m is about £104

[mike]

Avoid Floplast joints.

I used these once and ended up having to replace them weeks later because they were all weeping. Screwfix refunded me (+=A350 voucher) and took it up with the manufacturer. There had been previous known problems which were supposedly cured. The =A350 didn't make up for the hassle of removing kitchen units.

There were many complaints on the Screwfix forum at the time which I only discovered after fitting the wretched things.

[dennis]

I have plastic and copper in my CH and in my mains water systems. Its only been in there for 30 years so I can't vouch for its reliability.

I have had both copper fittings and copper pipe fail in my fathers house but they were about 40 years old. The copper pipe just developed a pin hole in the middle of a length for no apparent reason, soon fixed by putting a new bit in with plastic push fit fittings.

[dennis]

A bit pricy, TS are about 20% cheaper than that.

[ARWadsworth]

Here is an email from todays customer (an old email but I have known him a while)

"Without any authority I think the first waste pipes may have been made by a Dutch firm called Wavin who were owned by Shell (who supplied the polypropylene, and later ABS powder). Wavin set up a factory in Wiltshire and sold waste products under the Osma trademark, and still do.

This was followed by PVC rainwater gutter and fittings, at which point Kevin McDonald set up Bartol Plastics in Edlington in competition, later bought out by the Hepworth Iron Company of Hazlehead, makers of clay pipes. McDonald then left, set up McDee Plastics making skateboards etc, and then created Polypipe, in direct competition with Bartol, Wavin, Hunter, Paragon, and others.

Polybutylene pipe for drinking water was introduced by Bartol Plastics around 1982 under the tradename Acorn, to complement the fittings introduced in c1979; Acorn later was renamed Hep2o.

Hepworth Building Products was bought out by Wavin in 2005, just as I left."

My customer's (and he is now a friend not a customer) 1983 to 1984 Acorn fittings are still in working order. And that includes all the underground stuff used to water the garden.

I was happy to use plastic pipe for my CH install.

[David WE Roberts]

Pin holing normally due to sub-standard pipe. IIRC around the '60s there was a copper shortage and corners were cut in manufacture. We had to replace some a few years back.

[Stephen H]

Be aware that if you have existing copper tube notched in the top of joists under the floorboards, replacing this all in plastic could be tricky as if there are any Tees close to a joist, you would need to cut the notches deeper to accommodate the bulkier plastic Tees without fouling the flooring planks. You may end up notching more than 1/8 of the depth of the joist which will weaken the joists.

If you do decide to run new routes through the centreline of the joists these must be done within 1/4 and 3/4 of the lengths of the joists spans and no closer than 100mm to an existing notch or hole (unused or not)

Also bleeding them of air or draining them properly may be problematic if you do not keep the tube and fittings on the same level.

When I redid my heating, it was previously in copper and all in 15mm and as a single heating zone, I chose to use new copper.

I reused the existing notches, deepened to 22mm and as 2 heating zones (up and down) I thus avoiding accidentally weakening my joists.

Regards

Stephen.

[John Rumm]

+1

Never had the few I used leak, but they were a bugger to use, requiring considerable force to get the pipe to seat home correctly.

[David WE Roberts]

Are Floplast those nasty ones with the metal teeth so if you do a trial fit you can't get the buggers apart again? Got some of those by mistake, tried one and decided never again. I need to go and check my stash to see which ones I've used before - the ones which have a sliding out bit to lock them in place.

[David WE Roberts]

Ah - JG Speedfit.

[John Rumm]

They all have metal teeth AFAIAA... most can also be demounted though. Some need a tool to do it. The original speedfit design you just unscrew the end until it hits the "stop" and then unscrew it some more! It then comes apart.