110mm soil pipe locations in insulated raft foundation + Shower help

[HanleeHouse]

Hi all, I'm about to start work on drainage and insulated raft foundation in 2 weeks time. 

 

Please could you help with the drainage through the raft foundation? 

 

- Is all of the drainage that comes up through the raft 110mm? How far above FFL should they pop up? 

- Long radius bends with foot at each location? 

- There are 2 SVP's serving the FF. One serving a Master Bedroom Ensuite and the other Serving 2 en-suites. Do these need to extract through the roof or AAV in the loft? 
- Downstairs WC, does that need its own AAV? Does this need 2 outlets, one for sink and one for toilet? 

- Toilet in downstairs en-suite, can that connect to the same run as SVP?

- How would you deal with the shower tray in the downstairs en-suite? 

 

Any other general advice would be much appreciated too. Cheers!

 

 

- 

[Gone West]

@HanleeHouse I had an insulated raft foundation and all the 110mm soil pipes had long radius bends with feet and came up through the insulation and were around 0.5m above concrete level. That is except for the downstairs wet room shower waste where the 110mm pipe finished around 150mm below concrete level and was surrounded by a large block of polystyrene which finished above the concrete level. This enabled me to remove the polystyrene after the concrete had set and adjust the pipe length for the sunken shower waste. All the pipes had AAVs which were hidden behind false walls as the upstairs rooms had vaulted ceilings. We had our own STP and didn't have a vent on the house but on the STP.

 

 

 

Edited April 7 by Gone West

[JohnMo]

5 hours ago, HanleeHouse said:

How far above FFL should they pop up? 

Our pipes were below everything (at hardcore level, so about 450mm below FFL.

 

5 hours ago, HanleeHouse said:

How would you deal with the shower tray in the downstairs en-suite? 

We took 110mm pipe to the shower tray and then stopped screed / concrete with additional insulation, to act a mould. Once I was ready the insulation was removed, to leave a void to work with. The drainage fully completed for the shower tray, I back filled the space with concrete, then did flush fit shower tray.

[HanleeHouse]

49 minutes ago, JohnMo said:

Our pipes were below everything (at hardcore level, so about 450mm below FFL.

 

We took 110mm pipe to the shower tray and then stopped screed / concrete with additional insulation, to act a mould. Once I was ready the insulation was removed, to leave a void to work with. The drainage fully completed for the shower tray, I back filled the space with concrete, then did flush fit shower tray.

Thanks for that, I will look at doing the same.  

[Nickfromwales]

7 hours ago, HanleeHouse said:

Downstairs WC, does that need its own AAV? Does this need 2 outlets, one for sink and one for toilet? 

- Toilet in downstairs en-suite, can that connect to the same run as SVP?

If the invert (drop from vertical to horizontal) is less than 1300mm then no AAV required, push back if BCO insists!

 

SVP can take these without issue, providing the lot stays at 110mm (smaller pipe can be used if it's just a vent). Where solids are introduced there are rules to follow regarding the runs being pretty much straight to the inspection chambers, without any changes in direction. If you have to use a bend then rodding access should be provided where the soil stack appears above concrete / FFL. 

[HanleeHouse]

16 minutes ago, Nickfromwales said:

If the invert (drop from vertical to horizontal) is less than 1300mm then no AAV required, push back if BCO insists!

 

SVP can take these without issue, providing the lot stays at 110mm (smaller pipe can be used if it's just a vent). Where solids are introduced there are rules to follow regarding the runs being pretty much straight to the inspection chambers, without any changes in direction. If you have to use a bend then rodding access should be provided where the soil stack appears above concrete / FFL. 

Thanks @Nickfromwales Does the rest of the plan seem to make sense? Would you make any changes?

[Nickfromwales]

8 hours ago, HanleeHouse said:

There are 2 SVP's serving the FF. One serving a Master Bedroom Ensuite and the other Serving 2 en-suites. Do these need to extract through the roof or AAV in the loft? 

You can have the vent as a remote SVP stack, behind an outbuilding for eg, if you prefer to not penetrate the roof, but at the worst you only need 1x SVP and then the other can be an AAV.

 

8 hours ago, HanleeHouse said:

How would you deal with the shower tray in the downstairs en-suite? 

That depends on what it is going to be; tray / flush to floor tiled over wetroom former / other. Info please!!  Maybe show us pics of what takes your fancy and we can work from there 👍

[HanleeHouse]

12 hours ago, Nickfromwales said:

You can have the vent as a remote SVP stack, behind an outbuilding for eg, if you prefer to not penetrate the roof, but at the worst you only need 1x SVP and then the other can be an AAV.

 

That depends on what it is going to be; tray / flush to floor tiled over wetroom former / other. Info please!!  Maybe show us pics of what takes your fancy and we can work from there 👍

Cheers @Nickfromwales I've just measured out the en-suite and we're looking at having a 1400x800mm shower tray. I'm looking at something like this - Not looking to go flush, but just low profile. 

https://www.plumbworld.co.uk/hydrolux-low-profile-rectangular-shower-tray-1400-x-800mm-with-waste-19421-1270350

 

Thanks again