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Patio covering air bricks (& drainage issues)

Discussion in 'Building' started by jonnypron, 9 Nov 2018.

  1. jonnypron

    Joined:
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    Location:
    Thames Ditton
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    Hi,

    We had a patio done over a year ago, but have started noticing some damp and some smells. Upon investigating one possible cause could be that the patio seems to be badly laid and not following standard rules e.g. butting up against external wall too high, no drain for rain water and fall away from the external walls.

    Please see the photos included below. I now know patio should always be min of 150mm below air bricks / DPC, should fall away from the house and/or have a drain (French drain, soak away or join mains drain)... this doesn't even have a gutter space with gravel just mortared right up to the external wall.

    Any advice appreciated as I have the landscaper coming to check in a few days.

    Thanks.
     

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  2. jonbey

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    It can fall towards the house with proper drainage in place. But blocking air bricks is a bigger problem, especially if you have wooden joists.

    I assume all those holes were drilled to increase ventilation which suggests there were already ventilation / damp problems. Some parts of the patio is level with the holes, so that is going to cause a problem.

    I reckon a good channel drain, plus opening up air bricks as much as possible, and adding new air bricks in other parts of the house where possible, will sort it.

    But, if you can already smell rot, then that needs to be tackled.
     
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  3. jonnypron

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    not sure if it's rot smell, just some strange smell that comes and goes (a bit foul smelling so could be another matter altogether)... was fine in the summer but now it's cold again it's coming back now and again.

    The air bricks are nowhere to be seen on the side in the photos, just those holes and they seem to be about the same height as the floor inside which is confusing, unless angled downwards under the floor?
     
  4. jonbey

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    find a something to stick down them and see - if they are angled down and level with the floor, that is going make things wet pretty quick!
     
  5. lonner

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    Bit naughty
    Paving looks ok but you must remove at least 150mm away from the wall.
    Your just bridging the damp with it upto the wall with render on on it.

    Disc cut the 150 mm and reduce the bed, then add a bit of shingle .
    Make sure water can drain away, ie if its laid on old concrete ? You need to drill some holes or cut it out ..
     
  6. bobasd

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    your best bet for ground levels is to drop the patio and any high soil to the gulley rim heights.
    your gulleys all need grids.
    all pipes to discharge just above the grids/grills.
    some pipes seem to disappear under the patio - no gulley to be seen?
    all dischargin pipes except S&VP need trapped gulleys.

    massive splashin soakin render behind shed.
    green moss splash on other parts of render - whats the state of the gutters?
    bellcasts missin from the bottom of render.
    sand an cement plinths should be removed - they suck up moisture an bridge the DPC.
    the line of injection DPC holes probly means nothin.

    you want to get under the floor an check the joists tails for rot.
    post pics of any interior damp signs.
     
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