help with bathroom waste

[marko1965]

I will be starting my bathroom refit next week - would like some views on how to run the waste - have tried to draw a plan showing how waste will run (not brilliantly to scale ) - what I need to know is:

- How should I run the wastes for the basin and shower once they exit the wall - should I join them externally on the run back to the stack ( the basin waste exits the wall at a higher level than the shower waste) or should they join the stack individually.


- Where is the best place for any rodding eyes.


- Can the bath waste join to the toilet waste internally ?


- Someone has suggested that I run the shower waste in 50mm and the basin in 40mm - is this a good idea?


My shower waste is a 90mm high flow shower waste.

I'm putting a new stack in by the way .


Thanks for any help.

 

[shorticus]

OK let's see if we can help out.

First off, don't link the bath waste into the wc branch, run them out separately.
The basin waste is quite long so there is a risk of self induced syphonage caused by hydraulic jump, the risk can be reduced by going upto 40mm but this runs the risk of slowing velocity and thereby leaving deposits behind eventually blocking up the pipe. You may have to use an anti-vac trap, it’s not ideal but might be a last resort.
The best way to connect the wastes to the stack is individually however this could end up looking like a dog’s dinner on the outside of your house. So I’d be inclined to run one 40mm header into the stack and drop each waste into that. I see no advantage in increasing either the bath or shower wastes above 40mm.
As far as cleaning eye positions are concerned just imagine if you got a blockage how would you rod it? I always think that rodding eyes should allow you to rod towards the stack i.e. in the direction of flow, to me they just look wrong facing the other way, of course there’s the argument to face them into your house so you can get at the underfloor pipes if there’s a problem but IMHO it won’t look great.

 

[marko1965]

thanks for that shoricus - I'm looking at a straight through trap for the basin with anti syphon - would that be suitable? The outside of the house where the pipework runs is unused and not on view to anyone - I'm not that bothered what's on show so I may run everything individually.

 

[Billy Bob Bob]

i am with shorticus all to exit separately this avoids blockages and traps being sucked out bad smells being induced etc,in regards to rodding eyes they should fitted were ever the waste changes direction

 

[ecowarm]

2 Traps and Siphonage

To prevent smells escaping into a room modern sanitary fittings are trapped. Baths, sinks and wastes have traps added as part of the waste system. Modern WCs, of course, have an integral trap (the 'hidden bend'). In the early Victorian period traps were not so common and there are several contemporary accounts of installations without traps. The example on the left shows the sink layout in some terraced housing built in the first half of the 19th century. The sink wastes are not trapped and so depend on the trap at the foot of the waste stack. By the end of the Victorian period traps were used on all sanitary fittings. They were available in a huge range of materials, shapes and sizes. 'S' traps, 'P' traps and Q traps (all called because of their shape) were common styles and were available in lead, copper and sometimes cast iron. The examples on the left are from a 1932 catalogue. The bottle trap (another common type from the 1920s onwards) on the far left claims to be non-siphoning (nowadays normally spelt with an 'i' not a 'y') and is also provided with a screw base fro cleaning. Notice that, until the late 1930s or so, wash hand basins were referred to as lavatories. The right hand image shows two bath 'sets' - in other words matching taps, waste and overflows. Although traps prevented smells from escaping into the house there were situations where they could be broken. If a house was left empty for a long period evaporation could empty the trap. More common were problems of siphonage. Self siphonage can occur where water runs along a branch pipe. If the water flows full bore and fast enough it can suck all the water out of the trap. Induced siphonage occurs where a 'plug' of water running down the main discharge stack creates a vacuum in a branch pipe, again sucking the water out of the trap. Today, careful design ensures that these problems should not occur.The traditional approach to problems of siphonage was to provide ventilation pipes, usually fixed near the crown of the trap. As the water runs down the branch it sucks air down through the vent pipe rather than sucking water out of the trap. Induced siphonage is similarly prevented. Another solution, popular from the late 1920s onwards, incorporated anti siphon traps. If you spend some time looking at the Greenwood Anti-vak trap (left) you can probably work out how it operates.

 

[shorticus]

now now Marko, this is not the place to say that ugly pipework is ok, we're all artists here and pipes are beautiful to us, viva le plastique lol

 

[REDSAW]

i presume in the setout that the bath is under the window?

if so, dont forget that the glass unit needs to be toughened.