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