Height of wastewater pipes into BIGT

[umiq88]

Looking for some help. Have foundations down and starting dead work. Will soon be laying soil and waste water pipes.

 

Bath and Shower will be 50mm and sinks will be 40mm. Plan is to bring them individually down through slab and out through external wall into back inlet gulley trap.

 

Is the height of the pipes critical. I have not done this before and wondering if the connection into the BIGT is adjustable or fixed height. Photos or a sketch would be fantastic.

[Conor]

Do you have a drainage plan you can share? You would have needed something for your BC submission. You'll need to run 110mm pipe though the slab, not 40/50mm pipes.

[Russell griffiths]

As Conner said you need 110mm through slab and up, then change to 50mm

you can have the 50 in the screed or insulation but not to run down and out. 
 

back inlet gulleys are for plumbing in a small kitchen refit, or trying to get an extra hand basin out, not for anything new where you have the ability to do it correctly. 

[umiq88]

No BC over here for self builds. I've attached a copy of the plans to give you and idea.

 

Would you run one 110mm pipe into each bathroom and pipe the white wastes into that or should I have a 110mm coming up through the slab under each drain (sink, shower, bath etc)

 

Wastewater treatment is located at the top right 10m away.

Edited April 25 by umiq88

[ProDave]

5 minutes ago, umiq88 said:

No BC over here for self builds

Where is "over here"?  It would be handy to add your location to your profile so everyone knows where you are and what regulations apply.

[Temp]

22 minutes ago, umiq88 said:

Would you run one 110mm pipe into each bathroom and pipe the white wastes into that or should I have a 110mm coming up through the slab under each drain (sink, shower, bath etc)

 

The former can be easier. Typically each bathroom has a "stack" which is a vertical 110mm pipe in a corner. Pipes for the WC, shower and basin connect into this. The bottom of the stack under ground has a large radius vertical bend. The top of the stack either goes up through the roof and is vented to the outside or it terminates on the inside with an Air Admittance Valve. The AAV stops fast flowing water in the pipework sucking water out of the shower or WC trap. 

 

For rooms on the ground floor we sometimes run one 110mm pipe direct to the WC. 40/50mm pipes go out through a wall into a gulley. The challenge for this approach is getting the 110mm pipe for the WC in the right place. If it's too close to the wall the toilet seat might not stay up. 

 

If you want a walk in shower (or no plinth under it) special care and planning is needed when laying the slab. 

[umiq88]

Based in Ireland.

 

Thanks Temp that's very helpful. This is bungalow so everything is ground floor. 

 

I've checked dimensions for toilet so ok with that.

 

For 40/50mm pipes into gulley what height do you normally go through the wall at. Do you have a link to a gulley you normally use?

 

My floor is made up of 

 

75mm Screed, 150mm PIR, 100m Sub Floor Slab, 25mm Sand Blinding, 200mm Compacted Rock

[umiq88]

Like this. Only white pipe will be run internally and come out through external wall straight into boss pipe.

 

It will have to go above the slab in the insulation layer. Below that and it would penetrate the radon.