Plumbing with plastic pipe?

[Lacan07]

Hi all

I'll be plumbing my upstairs bathroom soon and I've been debating the best way to run the H/C water.

I've got a few options but they all have their pros and cons. I can notch the joists and run copper with either push fit or compression valves, (not really competent enough in tight spaces with a blow torch in old house), making use of some previous notching along the way; or I can run 15mm plastic pipe and go through the centre of the joists (although I'll need to notch 1 double joist at the end of the room).

The plastic pipe option is obviously easier with the push fit connections, and for making those awkward little bends, but I'm guessing there will be more hidden joints in total and its less neat. A hole through the centre will be less stress for the joist but blasting the holes in a small space won't be easy, especially the 2 new double joists!

Running copper is standard practice, notching is easy but its less kind to the joist, there's less flexibility and I'll have to invest in a pipe bender, but they'll likely be a few less joints overall if I can master the bending process.

I was just wondering what others on here have utilised for their plumbing? Any thoughts on the plastic pipes? I've read people warning of rodents eating the plastic! I've not seen any evidence of rodents in my house and I've taken it apart pretty much top to bottom, although my number reckons he sometimes hears scratching in his roof!

Cheers.

 

[Cubist]

When I replaced the kitchen sink a few years back I found the installers had used push fit plastics to connect to the copper services at floor level. As I disconnected the feeds to the mixer tap the network of approximately a dozen elbows and short pipe runs collapsed in a heap rather like a pile of spaghetti.

I've never been able to work out why the fitter, clearly not a plumber, needed so many elbows just to turn 90 degrees.

On the other hand, when I stripped out the bathroom a couple of years later I found that plastic pipe had been used to make new Central Heating service connections for a re-located radiator that wound its way under the floor through at least tow joists and various 90 degree turns without using a single elbow!

Personally, I hate the stuff, but I didn't see any mouse nibbles - give me copper every time.

PS - Push fit in 'tight fit' spots with restricted room for both hands can be very tough and nigh on impossible.

 

[Lacan07]

When I replaced the kitchen sink a few years back I found the installers had used push fit plastics to connect to the copper services at floor level. As I disconnected the feeds to the mixer tap the network of approximately a dozen elbows and short pipe runs collapsed in a heap rather like a pile of spaghetti.

I've never been able to work out why the fitter, clearly not a plumber, needed so many elbows just to turn 90 degrees.

On the other hand, when I stripped out the bathroom a couple of years later I found that plastic pipe had been used to make new Central Heating service connections for a re-located radiator that wound its way under the floor through at least tow joists and various 90 degree turns without using a single elbow!

Personally, I hate the stuff, but I didn't see any mouse nibbles - give me copper every time.

PS - Push fit in 'tight fit' spots with restricted room for both hands can be very tough and nigh on impossible.

Yes, its a dilemma with so many things to think about and consider. I'm personally not that bothered about the mouse nibbling, I work with 1/4' poly pipe and I've never witnessed a nibble despite seeing plenty of mouse sh*t. Its worth noting however that on the JGuest website they advise sheathing pipe and calling in the rat man if you think you have a problem. Not exactly confidence building.

I can't help feeling I ought to bite the bullet and try and solder copper. A friend taught me to use a soldering iron years ago when I started renovating old valve amps, once you pick these skills up you don't even think about it.

 

[Feltwell]

Plastic plumbing is undeniably very, very easy to use but I just don't trust push fit fittings in the long term, on plastic or copper. Why? They rely on little rubber O rings in them to keep a seal - and eventually they will perish. People worry the fittings will come loose, if inserted properly they never will, the water pressure keeps the grip ring gripping, but the O ring can fail.

I've used plastic in my garage, as it's better able to withstand freezing than copper - but in the house, it's copper and solder, or copper and compression if soldering is not possible.

Yes, have a go at soldering! It's very easy - I've taught folks in about 10 minutes how to solder - especially if you use "Yorkshire" fittings, the ones with a ring of solder already in them. Just remember a few golden rules:-

- You must clean the end of the pipe and the inside of the fitting, even if they're brand new, with some abrasive
- You must cost both in a thin layer of self-cleaning flux - not too much - when you assemble the joint twist it to and fro to ensure a good spread. Use a flux brush, flux is nasty acidic stuff
- I always use a heatproof mat behind the joint - helps reflect the heat back as well as protect what's behind
- Joints must be dry
- Even with Yorkshire fittings I do use a bit of solder to end feed

Skill Builder do some good videos, like this one:-

One very odd thing I found out is you can use compression fittings on plastic! Not tried it myself, but:-

 

[Feltwell]

Joists - there are rules for notching or holing joists, but I take them with a pinch of salt for an old house. I suspect they're designed around modern building codes for joists, in an older house the size and span of the joists needs looking at, certainly here the joists are much beefier than would be used in a modern house and they have a lot of redundancy - they're stronger than is strictly needed.

Having said that I do stick to the rules if I can.

https://www.labc.co.uk/news/how-get-it-right-notches-holes-solid-timber-joists

 

[CliffordPope]

Use wire wool not sandpaper - you don't want minute specks of sand embedded in the joint.
I too always run a bit of solder round the edge. I always clean the edge too, to give the solder more help wetting properly.
After experience of weeping joints after omitting that round the back of a joint because of access, I now always make a point of guiding the wet solder all the way round the edge, using a bit of bent solder if necessary.
It's important to heat the pipe not just the component.

I would never trust any plastic pipe or rubber in a section not normally open to access.

 

[Feltwell]

The other point I'd make is on waste pipe, always use solvent weld if you can. I had a hell of a job here getting underneath a shower cubicle where the bodging git who had installed it used a compression joint underneath, which they failed to support and which eventually came off, about 10 years later!

Solvent weld is easy enough to use, again just make sure to clean the pipe end and inside of the fitting with some solvent first (aerosols of electrical contact cleaner are cheap and ideal for this and 1001 other cleaning/degreasing jobs) and make sure you twist the fitting back and forth when you insert it - I put alignment marks on in pencil before using the solvent weld.

Compression waste is OK if you can get to it, it does have the advantage of being able to take it apart easily to clear blockages. Push fit waste is just a complete No as far as I'm concerned - just too easy to knock accidentally and loosen off a pipe.

 

[paulc]

- You must coat both in a thin layer of self-cleaning flux - not too much - when you assemble the joint twist it to and fro to ensure a good spread. Use a flux brush, flux is nasty acidic stuff

When done with soldering, wipe the joint down with water that has a good helping of bicarb of soda added - It will go someway in neutralising the acid flux and hopefully stop the copper corroding.
Oh, and if there are any cables in the vicinity, make sure they are kept away from any gas or hot water pipes. It also makes sense to insulate hot water pipes where possible.

 

[Lacan07]

Joists - there are rules for notching or holing joists, but I take them with a pinch of salt for an old house. I suspect they're designed around modern building codes for joists, in an older house the size and span of the joists needs looking at, certainly here the joists are much beefier than would be used in a modern house and they have a lot of redundancy - they're stronger than is strictly needed.

Having said that I do stick to the rules if I can.

https://www.labc.co.uk/news/how-get-it-right-notches-holes-solid-timber-joists

Yes, I'll always stick to rules with joists, it's a shame the previous people who did the CH and bathroom didn't! The joists beneath the bathroom have taken a bit of abuse, but I got 2 new double joists in when I removed the chimney and joist hangers just weren't going to cut the mustard with a bath above them.

 

[Lacan07]

The other point I'd make is on waste pipe, always use solvent weld if you can. I had a hell of a job here getting underneath a shower cubicle where the bodging git who had installed it used a compression joint underneath, which they failed to support and which eventually came off, about 10 years later!

Solvent weld is easy enough to use, again just make sure to clean the pipe end and inside of the fitting with some solvent first (aerosols of electrical contact cleaner are cheap and ideal for this and 1001 other cleaning/degreasing jobs) and make sure you twist the fitting back and forth when you insert it - I put alignment marks on in pencil before using the solvent weld.

Compression waste is OK if you can get to it, it does have the advantage of being able to take it apart easily to clear blockages. Push fit waste is just a complete No as far as I'm concerned - just too easy to knock accidentally and loosen off a pipe.

Thanks, I'm not that knowledgable about solvent weld although I'm well aware its the best way to go. The builder that installed my new soil pipe used it. I'll have to swot up on the subject.

 

[Lacan07]

Thanks for all the replies, as I thought a variety of opinions but more votes for copper on here than on the other forum I frequent. I've got access to the floor from both above and underneath but whilst my design is by no means ambitious or remotely modern I've probably made it hard for myself with a free standing bath. I'll have to run the water and drainage to find all the exit / entry holes but then remove all the bathroom fixtures again to do the floor.

If my plans are too tight I might end up having to run pipe work from an exposed shower valve up into the loft and then back down above the bath via the rose. Does anyone know if shower valve outputs via the riser are a standard fitting? And do building control like to see an access panel when you box in a shower valve?

 

[88v8]

Copper, always copper. One can solder very close to woodwork with the aid of a mock-asbestos mat, and importantly, always a plant mister to extinguish any fires.

Yorkshire fittings are easier, but end-feed is OK provided you can see the edge to make sure you have a full solder ring.

Have a couple of old cloths, wet them, and wrap them round the pipe either side of the joint to prevent the heat running away.

Practice on some spare pipe.

I use a blow lamp like this https://www.screwfix.com/p/bernzomatic-trigger-map-propane-brazing-torch/71976. Not this make, but this sort of thing.

Bends can be made with a bending spring. Bend the pipe to the required point and then relax it a little to allow the spring to be removed. Usually I use my knee or foot to bend over. 22mm can be a bit harder.
For 28mmm you would need a proper bender, but I've always been OK with fittings and never needed to bend.
Be patient when heating 22mm and 28mm pipe and fittings, it takes a while to heat through.

Ivor

 

[Cubist]

My bathroom project was rather extensive and included moving a internal partition wall and its door frame to create sufficient space for a full size bath and a large, and heavy, show tray. Barring for a short section where the water services entered the bathroom I surface mounted all the copper pipe-work and fittings. These occasionally need a spruce up with a little wire wool but are otherwise left to their own devices and have developed a, to me, rather pleasant patina. I also saved a small fortune by using brass garden taps for the basin and ball valves for the shower and bath. The most expensive component though, if I discount the micro shower pumps, was the antique rainfall shower head acquired during the First Ladies mooching's.

the only stuff the got covered were the unavoidable nasty plastic waste pipes.