Internal manhole connection

[Uggie]

Hi
I have an internal manhole As my extension was built over the top of an existing manhole in an area where I now want to relocate my kitchen.

My question is this

Am I able to connect my kitchen sink waste pipe directly in to the manhole as this is the shortest route for drainage.

Any advice would be very welcome.

 

[slapper]

Your existing Inspection cover will be room sealed to prevent any smells from it, if you compromise it then you could end up with a smelly kitchen, best to seek a Builders advice.

 

[Uggie]

A bit more information.

I'm not going through the cover I will dig a trench and insert 40mm waste pipe through brick work and then make good I want to know if it is good practice to do this or do I need to have 110mm pipe with a 'P Trap' and and 40mm adaptor to suit waste pipe. After this I'm going to lay 40mm floor screed and replace manhole cover with a new double seal cover to except floor tiles.

 

[slapper]

If the Manhole gets blocked, you could get effluent back up the waste pipe.

Best to do it in 110 with a P trap, with waste to gully

 

[Hugh Jaleak]

To comply with regs the underground section needs to be run in 110mm, with connection into the chamber made in direction of flow. Once at finished floor level, reduce down to appropriate size (40mm in your case) for the waste. If making a direct connection internally you wont need a trap on the 110mm section, the 40mm trap on the sink will suffice.

 

[Uggie]

Thanks Hugh

I have attached a sketch of my layout. I have decided to put 110mm pipe to manhole with an underground trap at the sink capped off with a 40mm adaptor for the sink pipe at floor level. This is because I will also be connecting a dishwasher to 40mm sink pipe and don't need to add additional traps if that makes sense ?

Kitchen layout

• Uggie
• 9 Feb 2014
• 2

 

[Hugh Jaleak]

Do not put a trap underground internally. When (not if) it clogs up with fat/waste food/other cr@p it'll be a pig to clean out, will stink the house out and make one unholy mess of the floor. Then somehow you have to try and get access, finding the waste pipe(s) are full of water, or the dishwasher has pumped out all over the floor whilst you were out the room....

You can run independant wastes into an adaptor with twin 40mm bosses, or simply couple both wastes into one 40mm waste, it doesn't matter. A 40mm trap is somewhat cheaper than the 110mm versions too!

 

[Uggie]

I hadn't considered blockage, I will just put an elbow in and add traps to the appliances as you suggest.

Thanks for your help.

 

[Uggie]

Job complete and working fine

 

[Hugh Jaleak]

Nice one.

 

[GavThePlumber]

Any pics of project?