Heavy Condensation in Conservatory

Discussion in 'Builders' Talk' started by saxopete, Jan 12, 2018.

  1. saxopete

    saxopete New Member


    Trying to help our elderly grandparents. They have a bungalow that already had a conservatory built when they moved in. They are suffering with severe condensation, beads of water on the rafters which is causing mould / dampness.

    They have tried opening the windows, damp catchers and running two dehumidifiers but to no joy. Doesn't help their washing machine is in there.

    I was going to suggest either popping a couple of air bricks in or putting a simple extractor fan in. Whats the peoples general opinion / advice for this type of thing? Just concious they are not young bless them and they are struggling to wipe if down daily and want to try and help them out.

  2. It is damp even with all the windows open? With a howling wind passing through? Blimey.

    Most connies are simply not designed for winter use - they are not insulated well enough, and usually don't have adequate heating either (which is good news 'cos it would be expensive). They should simply have the doors to the house firmly closed and the connie windows cracked open; only go in there if it's a bright sunny day and it actually feels warm in there.

    If the doors are left open to the rest of the house, then all the warm moist air in the house will go in there and condense out on the cold surfaces. The only way to prevent this from happening - if you insist on leaving the house doors open - is to raise the temp in the connie to at least match that of the house - and also add ventilation too.

    That will cost a fortune, and is nuts.

    Ok, if they DO have the doors to the house left open, they need shutting. Then leave the connie windows on 'vent' setting. That should keep it dry.

    If they insist on using the W/M out there, then they need to put on their winter coats, hat and gloves first and dash out there.
  3. Bruce Bennett LWT

    Bruce Bennett LWT New Member

    Have your grandparents considered converting their roof into a tiled roof? May be cheaper than heating all year?
  4. Saxo hasn't been back since...

    My understanding is that, in a standard connie, the roof is the weak point in terms of insulation and draughts. The windows - tho' there are a lot of them, so not ideal - are double-glazed so reasonably well insulated. Any dwarf wall is likely to be cavity, so that shouldn't be too bad either.

    The roof, however, is typically made from twin or triple-walled polycarbonate with the hollow ends often open to the outside air. Ergo the inside skin will be not far from outside air temps - that's bludy chilly right now.

    Also, they tend to rely on basic foams seals around the wallplates and ridges, and these are often draughty too.

    As far as I know the only way to make a connie usable all year round is to insulate the inside of the roof, usually by adding a secondary, well-insulated ceiling, either vaulted or semi-vaulted.

    This is ideally kept separate from the actual roof (which can be 'tiled' on the outside for aesthetics or just kept as is) with a suitable void where the existing draughts can happily carry on, keeping that void dry. The new ceiling should be fully vapour-barriered so that no moisture from the house gets through (most insulation materials will do this, although edges and joins should be taped to be sure to be sure).
    Bruce Bennett LWT likes this.
  5. Bruce Bennett LWT

    Bruce Bennett LWT New Member

    Fully agree here, some lightweight tile options can be found here: https://www.roofingsuperstore.co.uk/browse/pitched-roofing/low-pitch-solutions.html
    Deleted member 33931 likes this.
  6. Bob Rathbone

    Bob Rathbone Well-Known Member

    Looks like a classic case of warm wet air from the house being let into an enclosed cold area. The perfect combination for condensation. The doors to the house should be kept closed during the winter months, only being opened when the need arises. You can tell folks about avoiding condensation 'till you are blue in the face, they take no notice. As the washing M/C is in there, where is the washing dried? Oh, in the conservatory!

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