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Soil Stack & Extractor fan venting to loft

Discussion in 'Plumbing and Central Heating' started by Dazza Jones, 4 Aug 2017.

  1. Dazza Jones

    Dazza Jones

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    Afternoon all,

    Have just moved into a 10 year old 3 storey house and am slowing ploughing through the ever expanding list of problems, due mostly to lack of maintenance by the previous owner.

    Today i ventured into the loft to find what i think is 2 soil stacks (1 would be for 2 wcs and bathroom, the other for the en suite). They have what i think is AAV valves fitted. I also found 3 vents in the roof which are not connected to anything. 2 i guess were for the soil stacks and 1 for the extractor fan for the ensuite.

    Is it ok to leave the soil stacks as they are or should the roof vents be used? It does not smell in the loft.

    I cant see how it would be good for the extractor fan to be vented into the loft and so should be extended to the vent in the roof. The is no evidence of mould or anything nasty up there.

    Attatched is a few pics.

    Soil stack. Is this an AAV? One of these has a polystyrene 'cap'.


    IMG_20170804_122114.jpg
    Unused roof vents x2. (the pipe had fell off one and was on the insulation)

    IMG_20170804_122131.jpg

    Extractor fan from En Suite

    IMG_20170804_122151.jpg

    Thanks
     
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  3. stem

    stem

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    AAV's are designed for use where soil / vent pipes finish inside the building. They contain a one way valve and only let are in. (hence 'air admittance') Nothing will come out, assuming it is fitted and the joint is airtight. I have one from a downstairs WC inside a fitted cupboard in the utility room, there has never been any smell.

    You should however get the bathroom fan connected to the roof vent. I am surprised that if you use it, and it's working properly (ie that it is designed for ceiling mounting and any back draft shutters are opening) that there isn't evidence of damp in the roof space caused by steam condensing in the cold roof surface in the winter. I personally would insulate the duct, I have seen instances where steam has condensed on the inside a cold vertical duct and dripped back through the fan into the bathroom. If it's a real problem, condensate traps can be fitted, which catch any condensation. They are rarely required though.
     
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  4. Dazza Jones

    Dazza Jones

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    Thanks Stem, i will leave the AAVs as they are then.

    I can only find insulted flexible ducting for the extractor fan. Would this be ok to use or do i need to source some solid pipe and fittings to meet the roof vent.

    Thanks for the heads up regarding the condensation trap, if i spot anything dripping back in i will be sure to install one.
     
  5. Kind of a suprised this was not identified during a survey either for purchase or rent.
     
  6. Dazza Jones

    Dazza Jones

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    Some we knew about, some have been nice hidden surprises haha.
    ☺️
     
  7. stem

    stem

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    That will be fine, it's what it is designed for. It is not somewhere that it is likely to be disturbed or on show.
     
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