Water dripping from roof in attic

Discussion in 'Homes and gardens' started by Neil_Ireland, Dec 28, 2009.

  1. Neil_Ireland

    Neil_Ireland Frequent Poster

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    Hi,

    I was working on my pc when I could hear some water dripping, I opened the attic door and noticed it was wet on the inside and there is water dripping from the inside of the roof. Some of the insulation around the door is damp.
    No rain for the past day but it was cold last night -2 I think.

    Does this mean the attic is not vented properly, it's a new house.

    Thanks.
     
  2. Neil_Ireland

    Neil_Ireland Frequent Poster

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    Just had a better look up in the attic.

    There are droplets of water on the inner lining of the roof, seems to be only on the north facing part of the roof.

    Is this anything to worry about?

    Thanks,
    Neil.
     
  3. eamonn123456

    eamonn123456 Frequent Poster

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    Check out a couple of recent posts on this.
     
  4. Towger

    Towger Frequent Poster

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    Yes. Lack of ventilation, leak in roof, ceiling not sealed (warm air entering attic), or the builders favourite venting bathroom etc extraction fans directly into the attic. etc etc
     
  5. onq

    onq Former user

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    Neil, this is your second house post.

    Yes, this could point to inadequate ventilation.

    Do you have disconnected vents or downlighters in the ceiling?

    Did you have this house inspected by a surveyor or architect before you bought?

    ONQ
     
  6. Neil_Ireland

    Neil_Ireland Frequent Poster

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    No leaks that I could spot. Hotpress etc is sealed and the extractor fans are ducted to wall vents.

    My second post yes, the first being the settling cracks.
    No downlighters or disconnected vents from what I can see.

    I only had a snag completed before the purchase.
     
  7. onq

    onq Former user

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    Neil,

    If you click on my nic [ONQ] or eamonn123456's, click on the "statistics" tab and search for "all posts by" you'll see several recent posts about this problem.
    Failing thsi you cna use the search engine with keywords like "condensation" "interstitial" "ventilation" et cetera.

    Read up on what's posted so far and revert here with any queries.

    Basically in certain conditions, yes, moisture droplets can form on the underside of roofing felt.
    This usually doesn't affect the felt, but can affect the insulation it drips onto.
    Usually the incidence of moisture doesn't cause dripping off like this.

    If this is only occurring local to the roof above attic door consider sealing around it and insulating the back of it.

    ONQ.
     
  8. Neil_Ireland

    Neil_Ireland Frequent Poster

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    Thanks onq :)

    I'll do some reading.

    The water droplets are on the north facing side of the roof. Not isolated to above the attic door, this is sealed and insulated.
     
  9. roker

    roker Frequent Poster

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    I have notice my attic is wet on the inside of the roofing lining/felt below the tile, My house is 7 year old has vents in the soffits and a aluminium damp seal on the ceiling board,
    Could a de-humidifier be put in to the attic during cold spells?
     
  10. Neil_Ireland

    Neil_Ireland Frequent Poster

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    Same as I am seeing.

    Thanks to some advice from onq here I have sorted out my water storage tank insulation. The insulation should go all the way to the floor of the attic, mine did not.

    Heat was prob getting into the attic space because of this, will keep an eye on things and see if there is any improvement.
     
  11. eamonn123456

    eamonn123456 Frequent Poster

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    That kind of low level of heat getting into the attic would be fairly negligible I would have thought and in any case would tend to reduce condensation I would have thought.
     
  12. Neil_Ireland

    Neil_Ireland Frequent Poster

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    What do you recommend Eamonn?
     
  13. eamonn123456

    eamonn123456 Frequent Poster

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    I wish I knew! but just letting you know that insulating the tank is unlikely to solve it.
     
  14. Bob_tg

    Bob_tg Frequent Poster

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    Would a standard survey have caught this kind of thing? I've always wondered about surveys. A surveyor I used before did not even go in to the attic. They are full of disclaimers and only seem to spot the obvious.
     
  15. onq

    onq Former user

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    These are two different but related issues.

    1. Allowing heat from below to rise in a controlled way to prevent the water tank freezing.
    2. Reducing water vapour in the air sufficiently enough to let the ventilation provided clear away moisture forming on cold surfaces.

    The relationship is that warm air holds more moisture, ready for deposition on a surface which is below dewpoint temperature.
    Unless you know everything about the building physics of a space its difficult to predict what effect correct tank insulation may have.

    Factors to consider might include:
    i) Will the increased heat in the tank water lead to a greater rate of evaporation into the attic space?
    ii) Will the closed cell insulation board above the tank prevent movement of the evaporate enough to ensure there is no greater contravention?

    This is an extreme, and somewhat marginal, example.
    Such issues may be irrelevant to well vented older houses regardless.
    The effects of attic venting may be more of an issue with sealed, highly insulated homes.
    If that is the case, do not be surprised to see matters like this rearing their heads more often.

    Yes, there are sealed systems for heating [still needing an expansion tank IIRC] but AFAIK the main tank volume cannot be sealed.
    It has to allow for draining at a rapid rate and filling at a less rapid rate, which would displace air in any sealed tank volume.
    If it were sealed, it would probably need an external supply air or some sort of diaphragm system.

    As you can see, its not a simple science.

    :)

    ONQ.
     
  16. Neil_Ireland

    Neil_Ireland Frequent Poster

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    It's cold today, as cold as the day I first noticed the droplets and there are none forming now. I'll keep an eye on it.

    ONQ, I checked the rest of the attic and the foil back plasterboard covers the entire attic. Seems to be about a 3 or 4 inch vent gap around the eaves too. That's all I could see so far.
     
  17. onq

    onq Former user

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    3 or 4 inches? That seems excessive if its a continuous vent.

    The width for a continuous vent serving an "open" attic i.e. with no dormers or conversation is 10mm or less than half an inch.

    Where the attic is converted [the rooms follow the roof totally] or it has dormers [partial conversion with small attics to the side and above] the continuous widths need to be 25mm or 1 inch at the eaves and 5mm at the ridge.

    Here is TGD F:

    http://www.environ.ie/en/Publicatio...ng/BuildingStandards/FileDownLoad,1647,en.pdf

    Diagram 6, P.11 refers.

    ONQ.

    http://www.oneillquigley.eu
     
  18. roker

    roker Frequent Poster

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    I would be interested to know if the problems is greater with Tru-tone/slate type tiles. I would think that the older cement type roofing tiles would absorb the water and allow the roof to breath
     
  19. roker

    roker Frequent Poster

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    My storage tank and heating tank has been mounted about 6 feet up in the loft, on a timber frame, I don't know why, but it is imposible to lag it or keep it warm. Is there some new logic for doing this? possibly better pressure for the shower, should I get a plumber to relocate it above the hot press.?
     
  20. jeananne

    jeananne Frequent Poster

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    I have noticed several small damp patches on plasterboard in attic partial conversion near ( but i think unrelated to ) velux window in our 7 year old house - this has happened in the last week and I assume has something to do with the very cold weather and condensation...
    Checked out attic insulation and discovered one area between rafters, about 5 feet in length had no insulation at all ( I've filled in the gap with some spare ) and also in the main attic the extractor fan from the infrequently used ensuite vents directly into the attic space !!!
    Is this a big deal and can I fix it by attaching a hose and directing the extractor air to a nearby vent in the eves ???
    Also while i'm up there should i cover the 2 large water tanks and if so with what ?
    Thanks