"Jeff" wrote in message
...
Hi All,

I'm helping out with the re-plumbing of a house, the house has been gutted
and significantly extended. So rather than adding a new bathroom and just
joining the pipe work onto the existing pipes, I'm in the situation of
there's the domestic supply pipe we need a bathroom here and here etc.

My first question is really about the sizing of the pipe, the house in
question will have 3 bathrooms ( I've been told it has low mains
pressure);

Up-stairs bathroom 1 bath, 1 w.c, 1 basin, 1 mixer shower.
Downstairs cloak room with 1 basin, 1 w.c
Downstairs shower room with 1 basin, 1 w.c, 1 mixer shower

The owner has been advised by the builder that a 15mm supply will be
adequate, now I'm no plumber but when you also include the sink, washing
machine and dish washer into the equation and not forgetting the supply to
the combi boiler. I don't think this is right, gut feeling is 22mm (boiler
has 22mm connection anyway) reducing down to 15mm at the furthest point
seems to be more sensible. Anyone any thoughts on this?

My second question is more straight forward. Because of the location of
one
of the toilets, I need to lay a horizontal run of soil & waste pipe which
will have 2 toilets on it, what fall should the pipe have?

And lastly on the above soil & waste pipe, I believe its ok to use a
strap-on boss to join the basin waste to it as long as its not within
200mm
of the wc connection or does this only apply to vertical soil pipes?

Hope someone can shed some light on these questions.

Many thanks.

Jeff







Low water pressure . . . 3 bathrooms . . . . .combi boiler - forget it!!

If I were doing it, I would use a conventional boiler and have a large hot
water storage tank - and an even larger cold water storage tank. I would
plumb the hot water system in 22mm - except for a 28mm feeder pipe from the
header tank to the hot tank. I would use mains cold water - probably plumbed
in 15mm - to the kitchen sink, washbasins and toilets - and to fill the
storage tank. I would use stored cold water, plumbed in 22mm for the baths
and showers - and would use shower pumps to boost the pressure/flow to the
showers.

The above is based on gut feel rather than detailed science - but seems
reasonable to me.

I will leave others to comment on what you can and can't do with regard to
the waste water connections.

Roger