Search the forum,

Discuss washing machine waste pipe in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Messages
31
Hi guys.
I'm going to put my washing machine adjacent to my bathroom.

The path of least resistance to plumb the waste pipe would be under the bath tub.

Is this allowed?
If yes, would there be any issues with the bathtub draining slower or the washing machine waste coming up into the bath tub?

Thanks in advance
 
There wouldn't be an issue if the existing wastes are installed correctly with falls and ventilation correct and not blocked and the combined pipe is increased to 50mm, but it may not be worth the hassle if there is another way round it.
The only time it would come in the bath would be if the plughole is a path of less resistance than the actual drain.
 
Where does the bath waste go to? Take your washing machine to there.

There wouldn't be an issue if the existing wastes are installed correctly with falls and ventilation correct and not blocked and the combined pipe is increased to 50mm, but it may not be worth the hassle if there is another way round it.
The only time it would come in the bath would be if the plughole is a path of less resistance than the actual drain.

Thanks for the replys fellas.

My other option is to notch through 3 meters worth of joists and then to drill through a brick wall to connect to the sewage line.

Alternatively I could notch through 1.5 meters worth of joists and connect it to the sink.

Thanks again

CF
 
Even if you're in the right part of the span, there's no way to notch a 50mm waste into normal depth joists and meet building regs let alone get the right fall over 3m distance.
Boxing in above or below or in our case i dropped it straight down to the ground floor and ran out under the suspended floor downstairs as a 110mm pipe
 
Even if you're in the right part of the span, there's no way to notch a 50mm waste into normal depth joists and meet building regs let alone get the right fall over 3m distance.
Boxing in above or below or in our case i dropped it straight down to the ground floor and ran out under the suspended floor downstairs as a 110mm pipe

Thanks for the replys fellas.

Do I need a slope in the pipe? I was under the impression that the water pressure as it comes from above drum height would be sufficient to force water out of the pipe, even on a flat run.

Dropping the pipe to the floor below isn't an option because of kitchen units etc.

Which leaves me with the option of connecting the waste pipe (via a standpipe) to the bath trap or connecting it with a y connector to the pipe that goes out of the bath trap.

How would I go about installing this correctly?
 
Last edited:
It’s simple science mate water does not run uphill if you are talking about joining onto the underside of the bath pipework you will have all sorts of trouble on your hands
 
I thought as much
Thanks mate

How steep does this slope need to be?


How thin can these waste pipes go?
I've got some noggins underneath the joists to suspend the ceiling downstairs, I might be able to squeeze the pipe in the space between the noggin and the joist with minimal notching.
Not sure how much slope I'd be able to get with this sort of a system although it would be completely below washing machine level if this is any consolation.

Cheers again
 
Slope isminimum 18mm per metre. Only guttering can be laid level but it does affect the capacity.

Falls Must be carried through any junctions or branches.
Minimum pipe size would be 50mm but you might get away with 40 if you include an aav, and all other aspects of the system have good falls. However i can't be sure as i don't have that level of experience
 
Last edited:
To achieve what mate water still won’t run uphill
 
It will if the water can’t get away as fast as it is being released into the system. Or rather, it will back up. I don’t suppose he wants the bath filling with washing machine waste, or vice versa:eek:.
 
To be honest I think that is the least of the problems here
 
Thanks for all the comments fellas.
I've had a good look at my floor arrangement.

I can run the washing machine waste hose alongside the joists and through the brick wall

I've discovered a big standpipe on the other side of the wall that the bathtub drains into. I'll stick the washing machine hose into there.

Cheers
 
That is a good point, the actual waste pipe has to have the right falls etc, but before the air break you can do what you like within the manufacturers instructions. Some machines have optional extensions to the hous as long as you don't go too far above the machine base or vice versa.
 
Hey guys.

I came home today after the plumber had been.

To my horror, the standpipe entry point is level with the floor!

Admittedly, there is a decent slope along the joists until it meets the main sewage pipe outside, but its at ground level!

Basically, after he fitted the standpipe he realised that the washing machine would have to go on top of the stand pipe because space is so limited. So he took the upstand off and said the washing machine can be lifted off the ground with legs and the waste pipe can be routed underneath the washer into the standpipe (if you can call it that)

Is it really as bad as it seems?
My wife has paid him, he's been and gone and put the chipboard floor back together again.
 
Deleted - apologies wrong thread
 
Last edited:
Not sure why you haven’t gone with the pump option when we said the run was a bad idea

Not sure what you mean by pump option mate.

There were no advances to my last comment after I discovered there would be no notching involved and the perfectly placed standpipe outside so i thought that would be the way to do it.

I wanted the waste hose to connect directly to the outside standpipe but he decided to put a standpipe inside anyway, luckily no notching was required.

what remedial work do I need to carry out to make this work?
In theory the slope is perfect, if I shove the waste hose deep enough into the "standpipe" will the waste water be pumped straight out where I want it to?
From the physics perspective I can't see any need for the water to want to regurgitate upwards as the system is adequately vented with the right slopes.

Cheers again
 
The run between "standpipe" and outside main drain is about 3 meters.
From what I can tell the slope is sound.
The only issue is that the "standpipe" is level with the floor.

Cheers

IMG_20190506_234827.jpg
 
So the plumber left it under the floorboards rather than giving you a tall pipe to plug your waste into? that doesn’t make any sense there’s more to this. Is this going on a cupboard that’s not been built yet or something? Why would he not just bring a pipe up and attach a suitable upstand? Do you have any sort of trap under the floor to prevent smells coming back?? If he’s done it wrong and it wasn’t what you were expecting get him back. But make sure you’re in this time to tell him what specifically you want
 
Thanks for the reply buddy.

According to the wife, there was an upstand, but it was meant to be installed flush against the wall next to the white cold water feed.

The way he has positioned the upstand means that I won't be able to fit the washer in as the washer would have to be directly above the upstand. (Theres no space to fit it after the upstand)

The plumbers solution was to take the upstand out, raise the washing machine on legs and insert the flexible waste hose coming out of the washer directly into the hole in the floor.

I have no idea if he has fitted a trap without ripping the floor out :S
 
Simple answer is mate get them back you may not have a trap and additionally you are never going to know if it backflows and is overflowing under floorboards
 

Reply to washing machine waste pipe in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Creating content since 2001. Untold Media.

OFFICIAL SPONSORS

OFFICIAL SPONSORS

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock