Awkward Soil Sack in loft

[toontoonarmy123]

Hi,

We have a soil stack that is not vertical and the vent in the roof where it should ideally be connected is lower than the pipe (see picture). This means we have had to install a temporary flexi pipe for now but as it is not taught the condensation is pooling at the bottom. A colleague has suggested an air admittance valve but I suspect this needs to be connected at a vertical angle to the stack.

Any thoughts on either how to allow for a loft air admittance valve or connect a pipe to the roof vent without an angle to allow condensation pooling?

 

[CountryFan]

That black piece looks like loft ventilation, so you’d lose that connecting to it. You might be able to remove where th soil pipe connects vertically and fit your AAV in there (looks push fit).

 

[Madrab]

I would hope that the loft may be vented through the soffits?

If so then that vent is designed to take a flexible connection to connect the soil pipe out to atmosphere. You may need to alter the soil pipe to allow the proper connection but the flexi shouldn't be so loose where it can create a dropped section where condensation can collect. Is that a push fit socket where the soil pipe enters the loft and the 45 is connected into it? If so then the soil run could be altered easily to reorientate the run to connect to the vent properly

The alternative is a 90 bend from the vertical section, along to below the roof vent, with a min fall - straight up and then a 45Deg to connect to the vent. If a stack can be vented then that is always better than using a Durgo (AAV) IMO.

 

[HERTS P&D]

Soilstack or vent for bathroom fan?

Andy

 

[toontoonarmy123]

Soilstack or vent for bathroom fan?

Andy

Soil stack no fan

 

[CountryFan]

I would hope that the loft may be vented through the soffits?

I have no soffits, just that “breathable” membrane crap and had to install additional ventilation due to mould growth

 

[Madrab]

I have no soffits, just that “breathable” membrane crap and had to install additional ventilation due to mould growth

Oh right, no roof overhang, facia boards or eave ventilation as standard? Strange, I thought that had been a building reg requirement for donkeys, obviously not.

Wayhey .... every day's a school day!!

 

[CountryFan]

Oh right, no roof overhang, facia boards or eave ventilation as standard?

No there’s facia for guttering, possibly some roof overhang but definitely no eaves ventilation. I believe some builders won’t use the breathable stuff and opt for eaves ventilation instead - probably due to the issue I’ve mentioned.

 

[Madrab]

Building standards now specify that builders must provide specific ventilation for roof spaces for properties that have a pitched roof. In most cases that must be provided by a continuous gap around the eaves and a ridge venting system, it's now part of the Building regs - part C, 'breathable' membranes are no longer a substitute

7.2.15 Ventilation, vapour control and insulation - NHBC Standards 2019

nhbc-standards.co.uk