Mains cold water (ring circuit)

[dcawkwell]

My sister has built a house and the builder has done a cheap skate job
of the plumbing.

Water comes into the house straight to a 15mm stop cock and this supplies the whole house combi boiler and all. Not necessarily a problem however her house has 3 bathrooms with 3 showers, downstairs toilet, utility and all the other bits.

All the bathrooms have been supplied with one run of
15mm plastic pipe cold pipe.

As you can imagine if there is any serious demand in the house from more than one bathroom at once flow drops off to a trickle.

There are problems pulling up the floors as all the floors are now done,
it's laminate and tiled floors bathrooms are in and finished so would create a big mess.

My plan is to change the 15mm stop tap to a 22mm full bore and then keep the existing 15mm cold run but T another 15mm cold run to join up with the cold pipe in the last bathroom in the run going straight up into the loft and back down to form a ring circuit.

Question
Will this improve things? As water will now get to the demand
in two directions.

 

[Charnwood]

Not a lot of point if your property is supplied by 20mm MDPE or 1/2" Alkathene pipe.

 

[D_Hailsham]

My sister has built a house and the builder has done a cheap skate job of the plumbing.

Did your sister/architect/project manager etc approve the plumbing before it was installed?

 

[moggridgeplumbing]

You will still have the same problem of a lack of incoming mains flow rate, to service all the outlets. You need to upgrade the supply from the main stop valve outside the property I'm afraid, or change over from the combi system.

 

[Dan Robinson]

DC I have to say I am a little surprised to see you have a close relative come to this kind of problem ...didn't they ask your advise at any stage?