Pipes for water supply, waste and heating

[Jupiter01]

I am planning a bathroom refurb project and wanted to establish a couple of points/principles please.

I want to conceal all pipes.

Should water and heating pipes going in walls and under floors be plastic (HEP20 my preferred) or copper?

With the basin waste that pops out of the wall, should it be an elbow or a stub of waste pipe which I can then cut flush to tiles when fitting the basin?

Are there any factors which should determine whether I use the 32mm waste pipe v 40mm?

Thanks in advance.

 

[oldbutnotdead]

Pipes- copper or plastic can be inaccessible. Soldered copper joints are fine if inaccessible, plastic couplers less so. Waste pipe- make sure you'll have enough clearance to get a good fit on the stub if you go that route (depends on the size of your basin, is it pedestal)- that's the way I'd do it. Buried joints in the waste- solvent weld or pushfit, not the compression types.
Building regs govern when you have to use 40mm (runs more than 3m to the stack IIRC but you can check in the Approved Docs yourself). Don't think there's a downside to sticking 40mm everywhere (apart from the size) but happy to be corrected.

 

[Jupiter01]

My waste pipe runs are less than 3 metres before they hit the 110mm waste pipe connected to the pipe. That said, I will try to use 40mm waste if possible.
On my quest to conceal pipes, I am guessing that my fate is in the hands of the direction in which the floor joists are running? I assume that if they are running perpendicular to the direction of my waste pipe, I am not allowed to notch to the depth of the waste pipe and unlikely to be allowed to drill a hole (I know there are rules on the size and distance from end when drilling such holes) and it wouldn't help anyway as the pipe will be too rigid to feed through.

In this case, I would need to create a "box" to hide the pipes.

Do I have this right?

 

[bernardgreen]

I am guessing that my fate is in the hands of the direction in which the floor joists are running?

When refurbishing ( rebuilding ) the bathroom in this ancient cottage I was faced with ancient floorboards that could not be lifted and ancient sloping joists that could not be notched.

I created a level false floor minimum 25 mm above the existing floor and ran all the pipes ( and some cables ) in that 25 mm space. The only minor disadvantage is the step up to the bathroom floor. Fortunately the toilet is a separate room on the other side of the cottage so no soil pipes in the bathroom.

 

[Burnerman]

I hope its not an issue with you, but Ive known mice chew through plastic pipe and couplings.....unbelievable!
Also the polythene waste pipes degrade big time if they see the sun so its acrylic solvent weld everytime for me.
I did use the polythene stuff outside once, and its eggshell thin now.
John

 

[Ian H]

Don’t put the cold water too near the heating pipes.

 

[oldbutnotdead]

Correct (about the not being able to notch 40mm or even 32mm for a waste pipe). If you do end up having to box it in, think about making the boxing deeper (and higher) than is absolutely required- that way the top can become a useful shelf for Stuff

 

[Jupiter01]

One other possible scenario I wanted to run past you please: if the joists are running in the same direction as the waste pipe but there is a joist very close to the back wall, can I notch this in order to send up the waste pipe for my basin? It will be a real shame if despite the joists running in my favour, I still was unable to conceal the pipes.

I hope my explanation makes sense.