Drainage Changes

[Nigel_Cro]

I think this fits better in Building than it does in plumbing, apologies if I am wrong....

I am converting an existing shower room into a wet room. One of the problems is the fact that I need to lower the invert level of the drain from the shower.

In order then to get the necessary fall, I need to change the way the waste runs into the drains.

At the moment the waste runs through the cavity wall in 40mm and once outside the 40mm takes a 90 degree bend and drops into the top of a bottle gully which then flows via 100mm into an inspection pit. In order to get the necessary fall I want to remove the bottle gully and connect a new 40mm waste direct into the 100mm via a flexible converter.

The old shower waste was not trapped - the new one will be (Impey DSS1/H) so I am not worried about smell. I will be able to rod back from the inspection pit at least as far as the reducer and will be able to rod from the shower gully all the way to the inspection pit.

Will this work? Or have I got to have a complete re-think? I will probably be breaking the bottle gully out this weekend, so any help will be most gratefully accepted.

Thanks,

Nigel

 

[Hugh Jaleak]

Might be easier to connect the new 40mm waste into a boss on the side or back of the existing gulley?

 

[Nigel_Cro]

I did think of that, and it probably would have given me just enough fall. But, because of the design of the gully - forgive the lack of proper name, but it is a 'trapped gully' so going in at the side would just push the flow against the internal liner, not sure this is a good idea.

Also, I don't think there are any bosses that I can easily get to (but I will check again before I take the grinder to it).

Thanks....

 

[Hugh Jaleak]

Has to be trapped if connected to a foul sewer. Bosses are there to take waste pipes so I wouldn't worry about that, my main concern would connecting a ground floor shower directly to the drain, should something go wrong then there is a risk of raw effluent flooding into the room....

 

[Nigel_Cro]

Thanks Hugh,

I need to have another look at the gulley in the daylight - not sure, but I think I will struggle with the existing gulley.

I will have to get some catalogues out and see what is available - a trapped gulley with a low level boss... Shouldn't be too difficult.

And to think, I used to do this for a living (but that was over 30 years ago).

 

[Hugh Jaleak]

If it's any use to you, Screwfix do a bottle gulley with a removable 110mm plug in the back end. http://www.screwfix.com/p/round-top-gully/86226
Put a short piece of pipe into the back, then use this to connect your waste. http://www.screwfix.com/p/universal-waste-adaptor/51416#product_additional_details_container

Thats assuming your existing drainage is plastic....

 

[Nigel_Cro]

Yup - Existing is all plastic.

I may have to slightly realign the outgoing pipe to the inspection pit as the present gulley is hard against the wall of the house, but it is right on the corner of the 'new' extension, so I may be able to win some wiggle room.

Fortunately, everything is really shallow so there isn't much serious digging to be done.

I hope it stays dry for the weekend!!

Thanks again,

Nigel

 

[Hugh Jaleak]

Think forecast is dry but cold, so fingers crossed. Good luck with the digging!