Johnny Jekyll

Bathroom Soil Pipe To Run Externally

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We have a 1st floor bathroom to the rear of our new build and we have decided to exit the soil pipe through the building envelope straight away at that point and drop it down the outside wall, rather than internally dropping through the living room. Apart from sealing around the exit hole for air tightness, should I insulate the soil pipe at all (inside or outside)? Will I be causing any big thermal / cold bridge doing it this way? Thanks very much.

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1 minute ago, dpmiller said:

is it ventilated?

 

Sorry my plumbing know how is not great yet. I will try and explain. It is the furthest / last soil pipe in the run so I'm told it will also extend up the wall minimum one metre past the windows, and I presume be ventilated at the top. Does that make sense?

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1 hour ago, Johnny Jekyll said:

 

Sorry my plumbing know how is not great yet. I will try and explain. It is the furthest / last soil pipe in the run so I'm told it will also extend up the wall minimum one metre past the windows, and I presume be ventilated at the top. Does that make sense?

If you are on network / mains for sewerage, then each property has to provide a minimum of 1 vent to atmosphere.

Making that external SVP ( soil vent pipe ) your vent to atmosphere will encourage it to become a cold vent, but unless you have made provision for a vent elsewhere youll have to go for that regardless to satisfy the BCO.

Any other rising SVP can then terminate in an AAV ( air admittance valve ), making things easier for the other internal waste connections.

What you 'can' do is get BCO signoff and then take the vent cap off the external stack and replace it with another AAV, thus massively reducing the cold draught that would otherwise continue to be problematic.

Can you exit the building, then turn left or right slightly and drop / rise off to one side of the point that the pipe exits the building? Basically, if your stuck with the vent to atmosphere, can you put a bit of distance between the exit point of the build fabric and the natural (rising / passing ) path of the venting air?

What insulation has been used? I would recommend filling the gap around the pipe with expanding foam as it will help insulate the pipe.

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9 minutes ago, Nickfromwales said:

If you are on network / mains for sewerage, then each property has to provide a minimum of 1 vent to atmosphere.

Making that external SVP ( soil vent pipe ) your vent to atmosphere will encourage it to become a cold vent, but unless you have made provision for a vent elsewhere youll have to go for that regardless to satisfy the BCO.

Any other rising SVP can then terminate in an AAV ( air admittance valve ), making things easier for the other internal waste connections.

What you 'can' do is get BCO signoff and then take the vent cap off the external stack and replace it with another AAV, thus massively reducing the cold draught that would otherwise continue to be problematic.

Can you exit the building, then turn left or right slightly and drop / rise off to one side of the point that the pipe exits the building? Basically, if your stuck with the vent to atmosphere, can you put a bit of distance between the exit point of the build fabric and the natural (rising / passing ) path of the venting air?

What insulation has been used? I would recommend filling the gap around the pipe with expanding foam as it will help insulate the pipe.

Thanks for the help. I'm using full fill insulation using Cavity Therm. Is it possible to vent at ground level where the final main soil pipe runs out to the sewer? Or must the vent to atmosphere be at the end of the run where the rear bathroom is? In other words is it possible not to vent upwards where is rear external pipe is? Sorry real novice on this at the moment.

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1 minute ago, Johnny Jekyll said:

Thanks for the help. I'm using full fill insulation using Cavity Therm. Is it possible to vent at ground level where the final main soil pipe runs out to the sewer? Or must the vent to atmosphere be at the end of the run where the rear bathroom is? In other words is it possible not to vent upwards where is rear external pipe is? Sorry real novice on this at the moment.

The vent can be on any exterior elevation, can exit through the roof centrally on a stand alone SVP run etc but cannot vent at ground level near the property / adjacent to neighbours property / other point where the 'stench' would be a nuisance.

The vent is to get the gasses out of the network, so can get quite stinky.

As for the insulation, I'd buy some self adhesive neoprene insulation tape and wrap the outside of the pipe to the point it becomes exposed inside / outside, sealing and weatherproofing accordingly.

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1 minute ago, Nickfromwales said:

The vent can be on any exterior elevation, can exit through the roof centrally on a stand alone SVP run etc but cannot vent at ground level near the property / adjacent to neighbours property / other point where the 'stench' would be a nuisance.

The vent is to get the gasses out of the network, so can get quite stinky.

As for the insulation, I'd buy some self adhesive neoprene insulation tape and wrap the outside of the pipe to the point it becomes exposed inside / outside, sealing and weatherproofing accordingly.

Understood great thanks

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Just for your sanity, popping a soil pipe through a PH wall will not bring the 4 horseman knocking ;) 

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Posted (edited)
1 minute ago, Nickfromwales said:

Just for your sanity, popping a soil pipe through a PH wall will not bring the 4 horseman knocking ;) 

Sorry Nick what does PH stand for?

Edited by Johnny Jekyll

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Passive house ( aka well insulated build ). Sorry, a bit late and I'm cream krackered.

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Just now, Nickfromwales said:

Passive house ( aka well insulated build ). Sorry, a bit late and I'm cream krackered.

Ah yes : o ) thanks for your help tonight. Very kind.

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