Waste runs (again)

[crt]

I've followed bits of the helpful advice on waste issues and just wanted to check that what I've worked out for our new bathroom is sensible and will work.

1. We have existing bath and basin sharing a 32mm waste out to a gulley at the top of a stack (just waste, not soil pipe).

2. Plan is to install shower and move bath. Basin will remain where it is. Basin is near to stack on one wall, which is 2.6m wide. New shower and bath will be on 2.4m stud wall, at right angles to basin wall, with shower in the corner.

3. Result of this is that there will be a waste pipe from the bath running past the shower c.2.15m long, connecting to a run to go past the basin and out to the stack c.1.6m long, making a total pipe run c.3.75m. These runs have been calculated to provide a total fall of c.950mm on a 1:40 fall ratio. (Both bath and shower will need to be raised to allow for this fall).

4. My intention is to use 50mm waste pipe all the way along, connecting first the bath, then the shower and then the basin (using a 32mm T connector) with standard traps for each (though a shallow one for the bath).

Does anyone foresee a problem with this, e.g., all being on the same waste pipe? Or should I use a particular kind of trap? Should I use a particular angle at the join of the two waste runs or is a standard right angle joint ok?

Many thanks.

 

[Rico99]

You would be best using anti-vac traps on Shower and Basin so they don't get sucked dry when the bath empties.

Rico

 

[crt]

So....anti-vac traps even though I'm putting in 50mm pipe?

Thanks for prompt reply.

 

[Rico99]

Better to be belt an braces now than have to mess around later if it don't work properly.

Rico

 

[Bahco]

So....anti-vac traps even though I'm putting in 50mm pipe?

You are not talking hundreds of £ here! Might cost you an extra £2!

 

[TicklyT]

Better check your calculations of the fall - 950mm would be about 1 in 4, or did you mean 95mm = 1 in 40?

Bath and shower wastes are usually 40mm. Basin wastes are usually 32mm.

 

[crt]

Thanks. Concern is not cost, it's simplicity - are the anti-vac traps more or less likely to need replacing sooner rather than later?

 

[crt]

Ooops. 95mm of course.

Re 40mm, I read somewhere on this site that with longer runs sharing feeds 50mm pipe is recommended.

 

[Bahco]

there will be a waste pipe from the bath running past the shower c.2.15m long, connecting to a run to go past the basin and out to the stack c.1.6m long, making a total pipe run c.3.75m. These runs have been calculated to provide a total fall of c.950mm on a 1:40 fall ratio. (Both bath and shower will need to be raised to allow for this fall).

Can you explain especially the c. 2.15m etc

 

[Rico99]

They will need replacing no sooner than any other trap.

Just a slightly different design that stops the water being sucked out.

Rico

 

[crt]

Bahco - the reason for the long runs, particularly the 2.15m, is that we have to have the shower (double sized) and bath side by side but because of the positioning of the stack and the lay of the floor joists we have to take a long run across the front of the shower from the bath (pipe hidden by the shower plinth and step, bath waste in the centre) to the end wall and then turn left towards the basin and stack.

 

[Bahco]

Ok then

Good luck.