Shed insulation advice

  1. Rannsachair

    Rannsachair Forum Supporter

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    Location:
    Lochgilphead, Argyll, Scotland
    I have a 20 x 10 shed that I make limited use of as in the winter condensation coats all metal surfaces - so I do not leave good tools or motorbikes in it.
    [​IMG]
    It is of solid wooden construction: OSB sheets on walls with cladding on the outside and a coroline corrugated roof with some perspex type panels.

    So is there a method of insulation that will resolve this?

    If so am after advice on what can be done at a reasonable cost, any advice appreciated. I am not very familiar with building materials, I had to google to find out what OSB was to describe the walls.
     
  2. Rig Pig

    Rig Pig Member

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    Narrwich! U.K.
    I put glass wool in the walls and roof, covered it with aluminium bubble wrap as a vapour barrier and OSB clad the walls, zero condemnation issues and I can heat it with a small fan heater.
     
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  3. Rannsachair

    Rannsachair Forum Supporter

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    Did you have to add a frame to the walls and roof to allow for the thickness of glass wool?

    Probably a stupid question, though how do you get the glass wool to stay against the roof until you put the OSB in?

    Thanks
     
  4. Rig Pig

    Rig Pig Member

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    3,492
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    Narrwich! U.K.
    Mine is a prefab garage that I built up and modified to fit, I studded the walls out 4" the wall sections are cast dished so 6" glass wool stuffed in nicely. The roof is flat with 6" timber rafters, I cut the glass wool to fit inbetween with a saw while it was still rolled up and tucked it inbetween the rafters and supported it with duct tape stapled to the wood, then fitted the vapour barrier.

    It was a horrible job! I'll put a picture up after the school run.
     
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  5. Dcal Member

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    1,267
    Location:
    Antrim Northern Ireland
    As this is mostly wooden construction I'd say the worst of your condensation is coming from the roof.
    Any insulation will do the job but fiberglass, rockfall or polystyrene will work well.
    It is "very" important that you put in a vapour barrier between the existing roof / walls and the insulation and leave an air gap for air to circulate (low and high level vents) or you will have problems.
    The roof lights are your biggest issue (if you want to keep them) as you will need to maintain the ventilation paths through the rooflights
    How well do you want the building insulated?
    Do you want to heat it or just stop the condensation?
     
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  6. Burdekin

    Burdekin Chief Bodger

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  7. mrsbruce

    mrsbruce Forum Supporter

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    Livingston, Scotland
    Use bits of sticks marginally longer than the width of the gap. They can be ‘sprung’ into place, and will hold the wool in place until osb is fitted.
     
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  8. Burdekin

    Burdekin Chief Bodger

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    For the roof lights we used a double layer of twin 12mm polycarbonate and the sealed off the space with foil backed bubble wrap. These are the areas most likely to get condensation.

    Vapour barrier went under roof sheets and between OSB and cladding on outer wall.
     
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  9. Burdekin

    Burdekin Chief Bodger

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    Put the loft insulation in as you put up the ceiling.
     
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  10. Rig Pig

    Rig Pig Member

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    This is my setup, I plan one day to board the roof but it's a back burner job. The aluminium bubble wrap is reasonably tough, I have poked the odd hole in it with long stock but aluminium tape patches it up!
    20190429_090116.jpg

    The walls are handy as I can hang thing off them if I pick up on the studs.
    20190429_090135.jpg
    20190429_090146.jpg
     
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  11. garethp Forum Supporter

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    832
    sw scotland
    Some of our house roof has the insulation on the underside of the felt, its held in place with 1/2" wide plastic strips stapled to the joists, looks like what gets used to strap parcels.

    Once you've insulated and its also draft proof I'd recommend an electric dessicant dehumidifier, they work down to 0deg c unlike the compressor ones which are poor below 10deg
     
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  12. gaz1

    gaz1 Forum Supporter

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  13. Rannsachair

    Rannsachair Forum Supporter

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    Location:
    Lochgilphead, Argyll, Scotland
    It is mainly to stop the condensation, though if it gives me useable work area in the winter it would be a bonus.

    I would not be bothered if I did away with the rooflights as the LED strip lights I have give plenty of light.

    I currently have too much jammed into my integral garage.....


    [​IMG]
    [​IMG]
     
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  14. Rig Pig

    Rig Pig Member

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    I covered over all the windows when I did mine, the only one is in the upvc side door, it keeps it cooler in the summer and stops condensation creating rapid temperature changes.
     
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  15. Rannsachair

    Rannsachair Forum Supporter

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  16. Burdekin

    Burdekin Chief Bodger

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    For the roof then just insulate the rafter space with something like earthwoll and leave an air flow space above the insulation. I left a gap between the wall and soffit to vent each rafter space. Then board out with OSB. You just need to stop warm air from the workshop condensing on the cold roof.
     
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  17. mrsbruce

    mrsbruce Forum Supporter

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    1,153
    Location:
    Livingston, Scotland
    How about bubble wrap just before the osb.

    On both metal huts, I used bubble wrap insulation, but allowed for condensation to ‘run off’ and air circulation at the roof ridge, and the lowest parts of the roof. I may be wrong, but I believe that this has kept the dew point to the bubble wrap, and thus everything runs off to the outside. Think of it as a hut within a hut. In fact, with the internal lining, almost a hut within a hut, within a hut.

    Both huts remain dry, with the only sign of damp air being noticable, if they are left closed for 6-7 days. Even this goes once aired, or I run the diesel heater for a couple of hours.
     
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  18. Rig Pig

    Rig Pig Member

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    3,492
    Location:
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    I have bubble wrap insulated under the corrugated iron roof in my garage, it literally rained with condensation, the bubble wrap has completely stopped it, my car is very grateful!
     
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  19. Burdekin

    Burdekin Chief Bodger

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    Getting more expensive but you could also do metal roofing on top of the old roof. Part of my workshop is like that and never been an issue.
     
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  20. Rannsachair

    Rannsachair Forum Supporter

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    Location:
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    i suspect I will blow my budget on the insulation, membrane, strapping to create an air gap and OBM.
     
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