Long waste pipe run

[mondorich]

I am fitting a kitchen to my new build house and the drawings show a long waste run from the kitchen sink of about 5 metres to the soil pipe in the corner of the house.

On the way it will pick up the dishwasher outlet (next to sink unit), then the washing machine (utility room about half way along the run).

There is also a cloakroom basin that will need to discharge either into this waste run or separately into the soil stack.

Question is can I run this length of pipe and if so is feasible to run it all the way along the wall, given that the kitchen sink plug holes are some way away from the back of the units. I don't want to be cutting a hole in the side of the sink base unit unless it is right at the rear in order that the dishwasher slides in.

Also what size pipe can be used on runs this long?

Thanks in anticipation.

 

[bengasman]

Not sure I understand your question, where would you run the waste if not along the wall, unless you have a well accessible crawl space and your main waste is really deep?
Pipe size would be 40 mm and up.

 

[Gasguru]

5m is too long and an external pipe will look a mess.

Maximum lenght is generally 4m by upgrading to 50mm pipe, however you could increase this lenght by using an air admittance trap on the sink.

It would look better and be easier to install a gulley (perhaps with a back inlet) on the outside near the sink and feed short waste pipes into this. The gulley can run straight into the nearest access chamber or even tee into the run. Polypipe gulleys are rodable.

Run through your proposals with the BCO since it will be their decision.

Read Document H for some guidance.

 

[mondorich]

Not sure I understand your question, where would you run the waste if not along the wall, unless you have a well accessible crawl space and your main waste is really deep?

Pipe size would be 40 mm and up.

Thanks


The waste is intended to run along the wall, behind the kitchen units then through a stud wall into the utility, through a further stud wall into the cloakroom and then meet the soil in the corner of that room. So basically a long straight run with a dishwasher and a washing machine to pick up on the way.


The soil pipe emerges in the corner and protrudes up through the ground floor wich is a suspended timber floor. I will be fitting a boss at this point for the kitchen sink waste.

 

[mondorich]

5m is too long and an external pipe will look a mess.

Maximum lenght is generally 4m by upgrading to 50mm pipe, however you could increase this lenght by using an air admittance trap on the sink.

It would look better and be easier to install a gulley (perhaps with a back inlet) on the outside near the sink and feed short waste pipes into this. The gulley can run straight into the nearest access chamber or even tee into the run. Polypipe gulleys are rodable.

Run through your proposals with the BCO since it will be their decision.

Read Document H for some guidance.

I really have use the inside of the house because all the darinage is installed with that in mind. Thanks for the suggestion though about gulleys.

The drawings have been through BC and no comments were raised.

I will go back to my Architect tomorrow and seek his advice, given that he designed the layout.

 

[bengasman]

An architect advising on plumbing?
I can see 2 options here.
Make sure architect assumes responsibility for any problems that may occur.
Assuming now that architect will never ever be dumb enough to accept responsibility for something he does not understand, at least not in a practical sense, get a plumber to do this. A local one who is well established, gives written guarantees, and has insurance.
It will be a lot cheaper and less painful than a divorce when the missus finds out it is your fault her beautiful new kitchen leaks, stinks and needs to be taken apart.

I got one guy who has been calling me every so often for the last 3 years with an almost identical situation.
Inaccessible waste behind kitchen, too small, wrong angle and what have you. sometimes it leaks, sometimes it blocks, sometimes it stinks.
He must have called every plumber in the yellow pages by now and still has the same problem.