Planning Water Feed for En-Suite Bathroom

[MortarThePoint]

I'm trying to plan the plumbing of the en-suite. Thanks to @Nickfromwales I know what to do with my basin waste and I show that it brown and black below (brown in the room, black is in the wall). I then need to route the hot and cold water feed (shown combined as red below) around the room to the various places. It's going to come in to the room in the corner where there is a trench in the screed along the top wall to the bath. It's going to then have  to come above screed to reach the right stud wall before feeding the basins and continuing on to feed the shower. The shower and bath wastes have holes in the floor underneath the shower and bath. The feed may pop up under the bath rather than the corner, but that doesn't change much.

 

Where a right angle is shown in pipe below there may need to be an elbow or tee. Is it a good idea to clip the fed pipes to the OSB or does that make it noisy?

 

I am expecting to use something like push fit JG SpeedFit for the water feed, but am solvent welding the wastes. The length of pipe round the room is about 12m so if it's 15mm OD / 11.5mm ID (JG Speedfit pipe datasheet) the pipe volume is about 1.2litres. A shower running and 6l/m total and 3l/m each of hot and cold would take 24 seconds to pass that volume through. It's a bit of a shame because if I could get there direct it would only take about 4m of pipe and so take 8 seconds for the shower to heat up.

 

Is 15mm the correct size to use to feed a shower?

 

Bathroom wall layouts as viewed from outside the room:

 

Edited May 9, 2022 by MortarThePoint

[MortarThePoint]

I didn't like the sound of the extra 16seconds of wasted hot water so have punched a hole in the sole plate of the wall and the hollowcore concrete, below the word SHOWER, and the hot water feed can come up through there.

 

I now wonder if the cold should come up there too as will turning the basin tap on affect the shower temperature?

[Simplysimon]

9 minutes ago, MortarThePoint said:

 

I now wonder if the cold should come up there too as will turning the basin tap on affect the shower temperature?

can you reach the basin from the shower or is it likely you'll have more than one person in the bathroom at the same time?

[MortarThePoint]

3 minutes ago, Simplysimon said:

can you reach the basin from the shower or is it likely you'll have more than one person in the bathroom at the same time?

 

It's our main bedroom en-suite so high likelihood of basin and/or toilet being used at same time as shower. (and yes that second bit horrifies me too).

Edited May 9, 2022 by MortarThePoint

[Simplysimon]

6 minutes ago, MortarThePoint said:

(and yes that second bit horrifies me too).

mmmm... almost as bad as the en-suite in the bedroom without separating walls/doors, get up at 15min difference and don't worry about the taps being run

[Nickfromwales]

On 09/05/2022 at 15:52, MortarThePoint said:

I am expecting to use something like push fit JG SpeedFit for the water feed

Please don't, it's carp compared to Wavin Hepworth ( aka Hep2o ).

15mm for shower feeds, yes.