draining washing machine into cast iron soil stack

Joined
14 Jul 2009
Messages
47
Reaction score
1
Location
Middlesex
Country
United Kingdom
Hi, I would like to drain my washing machine waste into cast iron soil stack. I intend to drain the washing machine waster pipe into a normal 40mm open ended vertical waste pipe + trap, and then run a 40mm pipe between trap and soil stack.

The w/machine is on the ground floor. The soil stack only collects waste from toilet on first floor.

Is this possble , and if so how do you guarantee that their wont be no leak at the joint in the soil stack ? Also, what incline should the pipe between the trap and soil stack be set to ? Is one trap sufficient to stop toilet waste from back syphoning into wash/machine ?

Thanks in advance
 
Sponsored Links
There is quite a few old threads in the forum archives about Strap-On bosses for cast Iron ...and their £ expensive . But before you spend loads ,I would get a normal plastic one for a 110mm plastic soil pipe ( as your iron one seems similar) then try it for size . Cut the hole and seal the boss to the soil pipe with a hemp grommet smeared with with something like Evo -Stik all weather sealant. No this isn`t a wind-up . I did exactly that ( apart from the evo stuff ) way back in the 70`s and the joint lasted years with no leaks :idea: I know because it was an outside soil stack and I`m so sad I looked across at it every I drove past the house :oops: . Have a look through the forum for the "proper" way too ;)
 
Blimey, had to get my olde college book out to see what the fall/incline should be on 40mm waste. Most plumbers do it by eye, as its not an exact science. Anyhow the book says between 19 and 90 mm per metre. As I said its not an exact science, use your common/ use other waste pipes as a guide.

Secondly, traps are not there to prevent back siphonage. They will only prevent foul smells coming into the room from a waste pipe connected to a stack.

You may poss find that the force of the brown stuff coming from above will cause problems with your new pipe. You may need a secondary vent pipe on it.
 
Sponsored Links
thx again guys

whitespirit66: when you say that a secondary vent may be required, what exactly is required; a vertical pipe running alongside the cast iron soil stack upto and beyond the guttering ?
 
Ideally yes, but you'll get away with it terminating above the height of the WC
 
ok, so it should be a 40mm plastic pipe, connected to the waste pipe using a suitable T connector ?
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top