Waste drainage design.

[Barryscotland]

Needing advise, guidance with our foul waste drainage. First of all is it just the one waste pipe we need to run in the sub floor to each room that needs drainage then sort out the bath shower etc drainage through the insulation before the screed is poured? Also our SE design shows 4 SVP which in my mind means 4 pipes boxed in and 4 vents in the roof? Can there not be one SVP at the end of the run and AAV in the other rooms?

[Barryscotland]

2100078 DRAINAGE.pdf

[TonyT]

Best just ask the SE, it’s his design, there is no AAV on the drawing and BC have passed it.

[Nickfromwales]

I think you're interpreting the drawings too literally. There may well be 4 rising SVP's, but nothing stopping each of those, or just 3 of those from being terminated inside the dwelling with AAV's. You can have a strategic SVP to form the stench pipe ( open to atmosphere ) outside the property rising from the foul network up the outside to ridge height on a gable or just above soffit height on the other elevations. 

If you are on a terrace of houses or a street where you can demonstrate the neighbouring properties already vent the sewer to atmosphere, you could even petition the BCO to do away with a stench pipe altogether. 

The term SVP means network 110mm pipe runs in general, so it doesn't automatically become a pipe rising to atmosphere through the fabric of the dwelling    

[Bonner]

If I may jump on this thread ...

We have started building before I noticed what looks like an external soil pipe! Is this normal in a new build?

Can I just move this inside the corner of the en-suite? Does it need a 110mm pipe through the roof if so?

The room below is a study, would someone be able to hear things going down the pipe? ?

 

[Mr Punter]

16 minutes ago, Bonner said:

If I may jump on this thread ...

We have started building before I noticed what looks like an external soil pipe! Is this normal in a new build?

Can I just move this inside the corner of the en-suite? Does it need a 110mm pipe through the roof if so?

The room below is a study, would someone be able to hear things going down the pipe? ?

 

 

I am not sure how this will work.  Does the WC waste from the family bathroom go round a 90 bend and all the way out to the corner?  Is this in the floor zone or boxed in?  The rodding eye in the corner of the bath looks hard to access.

[Bonner]

Only drawing I have to be honest ? We are just getting out of the ground so need to ensure we get the drains through the slab in the right place. Then work out the first floor runs later ... Only got drawings for BC so lacking a few details 

[Bonner]

Yes, the idea seems to be running drains to the corner so at least we don’t have an external soil pipe on the front!

I would prefer not to have an internal drop from the family bathroom as it would be in the middle of the kitchen wall.

Expect the pipes will be under the floor (parallel to 254mm pozi-joists) but no idea how the rodding eye would work?

@Nickfromwales, any suggestions, internal or external SVP in that corner or somewhere else?

[Temp]

On 13/06/2021 at 20:44, Barryscotland said:

Needing advise, guidance with our foul waste drainage. First of all is it just the one waste pipe we need to run in the sub floor to each room that needs drainage then sort out the bath shower etc drainage through the insulation before the screed is poured?

 

He's only shown one SVP in each room but you should consider if that's the best approach. Its' not a bad starting point if you dont yet know the room layout. 

 

These days floor insulation and screed is quite thick but you might want to check there is enough depth to accommodate a shower tray trap and the fall to the stack without having to raise the shower tray up on a plinth. Perhaps you dont mind a plinth or perhaps you want wet rooms? Sometimes you end up needing the connection into the stack very low down or even in the slab. You wouldnt be the first person to have to chip out concrete from around the stack to get the connection low enough for the shower.  Consider making some room layouts to work out how far the shower trap would be from the stack. Then make cross sectional drawings showing the shower tray/trap, pipe fall, and branch connection into the stack to work out if its going to be an issue. 

 

An SVC in the corner and a WC pan with a horizontal P-trap outlet is easier overall than using a WC pan with a vertical S-trap outlet. With the former everything is above slab but you have pipes to hide. With the latter you need a connection coming up vertically through the floor but this needs to be just the right distance from the wall and makes layout changes later.  

 

 

There are many ways to skin that cat. Some people have no problem with boxing, some hide the pipe in cabinets, some build false walls, some hide the cistern as well as the pipe. Some use wall mounted pans. 

 

On 13/06/2021 at 20:44, Barryscotland said:

Also our SE design shows 4 SVP which in my mind means 4 pipes boxed in and 4 vents in the roof? Can there not be one SVP at the end of the run and AAV in the other rooms?

 

What @Nickfromwalessaid. The middle ones can be short stub stacks with AAV.

 

Only other comments i have is that he shows the red drain running under the house. Is there any reason why it can't be run along outside the footprint ?

 

[Dave Jones]

just to jump in on this thread. new build, external soil pipes look like dog crap. internal boxing the same. lose them in studwork if at all possible.

[Bonner]

21 hours ago, Dave Jones said:

just to jump in on this thread. new build, external soil pipes look like dog crap. internal boxing the same. lose them in studwork if at all possible

 

I agree, don’t know why the architect put an external soil pipe when we were going for a clean contemporary look. But my fault for not spotting it. Told the builder to move it inside where it can be hidden.

[Barryscotland]

On 14/06/2021 at 21:40, Temp said:

 

 

What @Nickfromwalessaid. The middle ones can be short stub stacks with AAV.

 

Only other comments i have is that he shows the red drain running under the house. Is there any reason why it can't be run along outside the footprint ?

 

 

 

Our static caravan is right in front of the house so we wouldnt of been able to connect it all up until the caravan was moved is the only reason I can think of. Spoke to the plumber and he is wanting a waste up through the sub floor at all toilets and showers and sinks. He did say we can use AAV in the house and we can run the one foul to atmosphere we need out the house and up the existing shed wall so dont need boxes up each room and out the roof.