In article , Peter
Charlwood writes
Just wondering if anyone has done this before and if there are any
potetial problems with doing it. Also i am installing a combi boiler
and was wondering what sort of pipe size i should use for the
shower/bath.

I would think 10mm would be to small for the shower/bath but doing
really want to go over 15mm due to space. what would be a reason for
having say 22mm pipe over 15mm.
I currently use 15mm copper for the 16m run to my bath and that is
adequate but I do have a very high head on my H/W supply (~20m). I did
try it with 10mm but it was just too small and the bath took ages to fill.

I have a 3m run to my kitchen sink in 10mm and that is fine but if the run
was any longer, I don't think it would be adequate.

Pros are less time to get hot water to the taps and also less wasted hot
water sitting in the pipe when you are finished, but cons are greater
interaction between taps eg, no flow from sink tap while filling a bath, but
you will get that with a combi anyway.

If I ever get this house finished it will have separate small bore feeds to
each bath/shower/large sink.

btw, be aware that plastic pipes have a smaller internal diameter than
copper and so will be more restrictive for a given (outer) size.
--
fred