utility room drains

Hi guys i need some advice have built my extension but now the utility room has not got an outside wall for me to take the waste out of. the extension will have a suspended wooden floor. Can i run a 4 inch soil pipe under this floor and up into the utilty room so i have mini soil stack in one ofthe cupboards in there which i can run a pipe from the washmachine /sink into . if this is ok obviously i have to go out the new extension wall to link up with a drain running along the outside , is it ok to go through the wall below the dpc . hope this all makes sense and someone can help me

i'm not sure i follow.

if there is a 110mm drain outside the building, then simply tap into this drain and extend the run so that you have a trapped drain gully directly outside the washing machine location.

there is no need to bring anything inside as it can all be done externally. this way all the 40mm waste pipes and the gully trap are serviceable.

hi thanks for that but the prob is the utility room is now not on an outside wall so the waste from it would have to go through another room around the wall to get to the outside wall.There will be a 110mm drain running the outside (below ground ) ill try and upload a pic or diagram to try to make it clearer as im probaly not making sense

hope thiss pic helps

You sketch is not very clear! Is that round thing in the corner a soil stack? & what’s that small room next to the utility, is it a w/c?

Being a new extension, I assume you will be getting a visit from a Building Inspector at some point to sign it off. He will want to inspect the drainage/waste runs & maybe witness a water test on any new connections to the foul drain so it’s important what you do complies with Building Regulations or he won’t issue a completion certificate!

the door openings in that utility make use of the space rather prohibitive.

provided you can achieve the falls then there is no reason why a 110mm pipe can not be taken into the utility area.

i would put a trap on the pipe though as opposed to bringing it up through the floor on a 90 degree bend.

drainage is the first thing you should be thinking about when setting out a utility/kitchen/bathroom, not the last!

I know i should have planned before but things got changed the round thing inthe corner is a soil stack but i dont think i can get onto that its cast iron and to change it would be a real headache. Next to the utility is a wc but agin tricky because the siol pipe from that goes straigt down and i have the doorway in the way. I thought coming below the floor joists through the new wall and the old wall and up into the utility with a stub stack and maybe an AAV on the top would be the best option but wasnt sure if this would be allowed The BCO is not very helpful on this front

I would say your best bet is out through the wall in the w/c into that soil stack even if it means cutting the cast iron stack at low level & replacing with a new UPVC stack using an adaptor. You can then use a boss or branch connector to get into the stack at the appropriate level & (looking at your sketch) you won’t need an AAV on that run.

Connecting into the existing foul drain at the nearest manhole is entirely possible but getting into it will create its own problems, especially if it’s an old brick build type. Limited info on the "not too good" sketch (sorry ) but, overall, I would say it would involve a lot more hassle than connecting to the stack; believe me, digging through a cavity wall below ground level is not particularly easy!

BCI’s are generally very helpful but you have to remember, their job is not to design the system for you but they will usually comment as to weather or not what you propose is going to be acceptable. If you don’t already have them, you need to look at the Building Regs.

http://www.planningportal.gov.uk/england/professionals/en/1115314110382.html
& one or 2 of the manufacturers have really good design guides which incorporate the regs.
http://www.hunterplastics.co.uk/content/1/94/soil---waste-support.html
http://www.marleyplumbinganddrainage.com/diyer/downloads/19/product-guides.html
these should allow you to see what’s best in your circumstance & will ensure your BCI will pass it which, at the end of the day, is the most important aspect. Have a look & come back if you need more.