Loft ventilation?

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Hi we are having our wooden soffits and fascias covered with uvpc and where wondering about loft ventilation as at the moment we have none.

Our builder is going to put in 5 soffit vents - will these be sufficient and enough? At the moment there is a lot of condensation in the loft and mould on the walls in the rest of the house caused by condensation. The loft measures about 10m x 10m approx
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  • allan673
    allan673 Posts: 1,213 Forumite
    First Post First Anniversary Combo Breaker
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    hi,
    if your having 5 x 70mm diameter vents then this is no where near enough, and the builder is clueless.
    to be honest you need soffits that are fully vented (have vent strips running all the way through them). otherwise your loft will continue to sweat and condensate. every loft needs to be able to breath, therefore you need lots of air circulating through it.

    i would also fit 4 vent tiles in the roof (2 on each side), ive had these fitted in my roof. any roofer will do these, simple to install. my roof tile vents are marley double romans and theyre around £30 each. expensive but worth the money.
  • keystone
    keystone Posts: 10,916 Forumite
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    perc wrote: »
    Hi we are having our wooden soffits and fascias covered with uvpc and where wondering about loft ventilation as at the moment we have none.

    Our builder is going to put in 5 soffit vents - will these be sufficient and enough? At the moment there is a lot of condensation in the loft and mould on the walls in the rest of the house caused by condensation. The loft measures about 10m x 10m approx
    Covering up the old timbers is not a good idea frankly TBH. They will rot underneath and when he tries to put the guttering back on top it won't fit unless he's replacing that as well.

    The old timbers should come down and the new soffits and fascia boards fitted directly to the rafter feet having first inspected the sarking felt to ensure it doesn't need replacing.

    The new soffits should either be fully vented like this:

    white%20vented%20soffit%20feather%20edge%2001.jpg

    or if he is using plain soffits they need these:

    ryton%20white%20vent%20s.jpg

    spaced at 160mm centres. Thats a tad more than 5!

    Cheers
    The difference between genius and stupidity is that genius has it's limits. - Einstein
  • andrew-b
    andrew-b Posts: 2,413 Forumite
    First Anniversary
    edited 19 December 2009 at 8:27PM
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    Covering soffits/fascias with uPVC rather than removing the timber and fitting new uPVC roofline wreaks of cowboy and is not the recommended way to do it. Any rot in the old boards will continue rotting behind the uPVC cladding hidden from view - eventually whats attached to them will probably start falling off. Get it done properly with the first row or two of tiles removed (or pushed up), old soffits and fascias taken down, new sarking felt or boards (called eaves protector), ventilation system, bird comb etc, soffits, fascias, replace tiles and then new gutters. You should be looking to spend about £50 per meter of roofline for a decent job.

    Our new soffits and fascias have a ventilation system at the top of the fascias the entire way round - can't see it unless you look closely. Insulation in the loft should be moved away from the eaves so that you can feel a draught all around the eaves.

    Link to the system we have: http://www.freefoam.ie/contentfiles/pdf/eaves%20protector%20brochure.pdf

    For what it's worth we were originally going to paint up our old soffits and fascias ...but when the gutters came off and the boards were removed it became evident just how rotten the fascias actually were!

    I'd leave any vent tiles for now and wait to see if you still have condensation problems after.
  • vicstick86
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    Ive got a 1960's house with UPVC covered soffits, and had it insulated.
    Went to get the christmas decs down and low and behold the loft was dripping it was literally like a cave.
    noticed that we had no ventalition up there. on our house you cannot reach the edge of the roof from the inside, as theres a inch gap then a large void. So it isnt easy to vent really
    So I sent my boyfriend up a ladder and he drilled four holes through the soffits on each side and put 70mm white vents from screw fix in...it did the trick, its been a week and our lofts pretty much dried itself out...
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