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Barn Shed - air flow to minimise condensation/mould

Discussion in 'Garden Projects and DIY' started by NAlberto, Jul 19, 2021.

  1. NAlberto

    NAlberto Apprentice Gardener

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    Hi all,

    wanted to get some opinions around getting air flow on my shed.
    The shed is a "barn" where the roof is split into 4 parts making the curved roof.
    The issue that I found straight away is that mould started growing on the rood side that does not catch air; this is due to not being able to open the windows therefore there is no air flow (the only way to get air flow is to open the door).

    I am thinking to put two Stainless Steel Round Air Vents Round Type Bull Nosed on one of the sides and a Manrose extractor on the other side to create some air flow.

    my query is; would these work best at the bottom of the wall or close to the roof?
    if anyone has any other suggestions, I would appreciate.

    Thank you
     
  2. JWK

    JWK Gardener Staff Member

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    Welcome to the forum @NAlberto

    Before answering, can I ask what is in there to cause mould and why you can't use the windows?
     
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    • JR

      JR Chilled Gardener

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      I guess the windows are on the roadside and that's why you can't open them (collision and security)
      I'd put the vents near the top particularly the manrose extractor. You could put vents top and bottom on the other side.
      I've noticed that traditional barns had a lot of ventilation between the upper walls and the roof which makes sense with all the damp stuff that farmers store.
       
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        Last edited: Jul 20, 2021
      • NAlberto

        NAlberto Apprentice Gardener

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        Thank you JWK

        The windows are screwed in place and speaking with the vendor, it seems that only the walls are treated, the floor and roof shiplap are not. the shed was put up at the end of last year and it was empty for a good couple months. within like 2 months I could see mould starting to grow, where I started to open the door when I could to minimise it.
         
      • NAlberto

        NAlberto Apprentice Gardener

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        the attached image 6477 was taken in Jan this year.
        probably better to add that the roof has torched felt on and also that this shed is not a "traditional" barn, it is what they call the mini dutch barn (tiger mini barn)
         

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      • JWK

        JWK Gardener Staff Member

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        Those pictures help, yep definitely a ventilation issue. Well an extractor would help if there is no alternative, but I would first look at making the windows openable. There really should be some ventilation in the roof as well, it's unusual for a shed to be completely sealed. I'd have thought a couple of vents top and bottom would work on the opposite side. I guess if you intend to store tools and don't want them to rust then consider mechanical extraction but that seems expensive if you can do it naturally.
         
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        • Giri

          Giri Gardener

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          ... and in the mean time, as a temporary measure, put something metallic in there, at night it will be colder than the wood and attract any condensation.
          Nice shed by the way ...
           
        • NAlberto

          NAlberto Apprentice Gardener

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          yea, it is the kind of oversight that someone like me that never had a shed before doesn't know when ordering it. these companies could provide this advise though, but yea, that would be the ideal world.

          thinking to use 2 of these on one side, 100mm ones though.
           

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        • NAlberto

          NAlberto Apprentice Gardener

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          I got one of these racking systems but this was after last winter.

          and thank you
           

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          • JR

            JR Chilled Gardener

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            Seeing the shed leads me to think that a couple of ventilation grills one either side would probably suffice.
            As JWK says opening windows would be good too. I'd fit top hinges.
             
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            • JWK

              JWK Gardener Staff Member

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              Those interior photos of the mouldy timber indicate it wasn't treated. I would slap some preservative on there.
               
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              • pete

                pete Growing a bit of this and a bit of that....

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                This time of the year my wooden shed is like an oven inside and there is no sign of moisture.
                It has no ventilation and doesn't get condensation, just wonder if dampness is coming up from under the floor, I assume there is free airflow under the floor.

                Condensation on the roof, I assume only in winter, could be dealt with by sticking 25mm celotex or similar to the roof.
                But I think you might have a damness issue from below.

                The mould is obviously just a sign that the dampness is there and not really a problem in itself.

                The part circled as mould looks like the kind of defect that you often get in softwood timber these days, it will be ok if its kept dry, but will rot quickly if it remains wet.
                 
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                • Sheal

                  Sheal Total Gardener

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                  I bought my shed, it's three years old and doesn't have windows. You can see there is a plastic vent about four inches in diameter above the door and also one on the back. I've had no problems with dampness at any time of year despite where I live.

                  043.JPG
                   
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                  • pete

                    pete Growing a bit of this and a bit of that....

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                    I've just had another look at the mould area in the pictures and can see a clear line in it which looks like it had something leaning there.
                    So it probably is just surface mould and not what I originally thought I was looking at.
                     
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