Below Ground Drainage Connection

Hi all,

I'm looking at a new project at home to form a Utility Room by stealing some garage space.

Looking to change from this





To this



I've drawn it all up and started cutting out bits of boxing etc... to make sure my plans work and identify where the services run, BUT I've hit a problem with the waste pipework which is routed as below



This puts it right in the way of what will be the newly formed corridor into the Utility Room!!

So I've got 2 options as I see it

1 - Dig out the current pop-up and relocate it ~1-metre away as per the below



OR

2 - Re-route the drainage to an external SVP which can now be accessed as the back-door is also moving and cap off the existing pop-up as per the below



I'd rather not have a long run of horizontal external waste pipe as we had issues with this freezing at a former house and the pipework would run from a shower.

Any help/advice would be much appreciated (including if I need to get the BC involved) or if there's a third, fourth option etc...

If you want to cap the existing drain off, looking at its location in the proposed layout, you will need to cap it under the floor. I would first look at the possibility of moving the drain position under the floor to a suitable point to reconnect the appliances. You're moving the WC position etc, how does that work with the existing drainage?

Alternatively, although you dont say where the drains are externally, if you must run the waste to an external position, it would be far more preferable to install a gulley, and connect to the nearest suitable point on the sewer, with the stack nearby, then it cannot be too far.

BCO will need to be to be notified as you are making alterations to the drainage system.

Hi, thanks for the reply.

To be honest I’m not too happy with the idea of capping a drain and then having flooring fitted above it (I had some sort of a hatch in my mind for this option) but didn’t know if digging out a channel in the existing slab to move the pop-up was realistic, or whether it was something that was a non-starter.

The external drains run towards the bottom-right of the drawing (I think) as there’s an access hatch on my drive.

re the WC soil pipe the current connection position is directly below the WC itself so my plan was to run a new soil pipe around the perimeter of the new room layout and box it in with the new WHB waste running to meet it.

So just to confirm, I would need BCO sign off for either option?

Thanks again

You'll need Building Control to do any of this work - converting a garage is under Permitted Development rights but you still need to notify it and have it signed off. Failure to do this could affect your house insurance

I would be involving Building Control before you do much more, they're there to help, and will indicate what they are prepared to accept. When you refer to a 'pop up' do you mean a stub of 4" drain sticking up from the floor? I'd be looking to move it to a suitable position under the floor, and reconnect the washing machine etc back into it, given you've a shower waste coming from above, you also need to be mindful of the maximum permitted length of the run. (3m for 40mm pipe, can go slightly further if using 50mm.)

Cheers guys.

I’m still pricing it all up really to decide how much to do myself or whether to get a firm in to do it all (main reason for it is for somewhere to put our wet/muddy pup after walks!!)

I’ll get in touch with BC and see what they say.

Thanks for the help