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Multiwall Polycarbonate Roofing - Thickness

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  • 08-04-2019 4:40pm
    #1
    spockety
    Moderators, Education Moderators Posts: 5,446 Mod ✭✭✭✭


    Quick query on Multiwall Polycarbonate sheets for doing a garden area lean to, about 5m x 4m on a wooden frame. It comes in thicknesses of 4, 6, 10, 16, and 25mm. The suppliers suggest 4 & 6mm for greenhouse type applications, and 10mm+ for carport roofs and the like.

    Assuming they are secured correctly as recommended (bars on the joints, fixing buttons on cross members and intermediate rafters, etc.), will be carrying no weight/load , why would it not be recommended to use 4 or 6mm for a lean to roof? They're a good bit cheaper, etc.


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    #2
    Lumen
    Registered Users Posts: 31,009 ✭✭✭✭Lumen


    Too thin, weak and flexible.

    I've only got experience of 10mm, and that still has a decent amount of flex it it.


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    #3
    CJhaughey
    Registered Users Posts: 14,906 ✭✭✭✭CJhaughey


    Wind will tear thin sheets off a roof easily due to pressure differentials, hard to imagine but it is very destructive.
    There is a reason that the heavier wall stuff is specced for different applications, and that is strength.


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    #4
    _Brian
    Registered Users Posts: 18,475 ✭✭✭✭_Brian


    We have single wall corrugated poly on a small roofed deck.
    It’s taken massive winds as we live in a very exposed area. It’s 8 years up now and lost maybe 20% of its opacity.


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    #5
    spockety
    Moderators, Education Moderators Posts: 5,446 Mod ✭✭✭✭spockety


    _Brian wrote: »
    We have single wall corrugated poly on a small roofed deck.
    It’s taken massive winds as we live in a very exposed area. It’s 8 years up now and lost maybe 20% of its opacity.

    Interesting, what thickness?


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    #6
    blackbox
    Registered Users Posts: 4,102 ✭✭✭blackbox


    _Brian wrote: »
    We have single wall corrugated poly on a small roofed deck.
    It’s taken massive winds as we live in a very exposed area. It’s 8 years up now and lost maybe 20% of its opacity.

    I had corrugated poly on a car port and there is now about 20% of it left!


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    #7
    Qwerty?
    Registered Users Posts: 1,243 ✭✭✭Qwerty?


    I went with 25mm but my run is over 5m and very exposed


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    #8
    _Brian
    Registered Users Posts: 18,475 ✭✭✭✭_Brian


    spockety wrote: »
    Interesting, what thickness?

    I don’t know, it was installed when the deck was built by a contractor.


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    #9
    mloc123
    Registered Users Posts: 9,454 ✭✭✭mloc123


    I always assumed it would stain/go green over time... Does it not?


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    #10
    fiacha
    Registered Users Posts: 779 ✭✭✭fiacha


    mloc123 wrote: »
    I always assumed it would stain/go green over time... Does it not?

    I was looking into replacing glass panels on a greenhouse with multiwall polycarbonate. I was told that each panel needs to be sealed and taped to prevent water / insects / moss etc getting in.

    Any natural staining on the surfaces can be washed off.


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    #11
    _Brian
    Registered Users Posts: 18,475 ✭✭✭✭_Brian


    mloc123 wrote: »
    I always assumed it would stain/go green over time... Does it not?

    It does a bit.
    Only glass will stay 100% clear.

    After 8 years ours is about 80% clear.


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    #12
    tradesman
    Banned (with Prison Access) Posts: 390 ✭✭tradesman


    spockety wrote: »
    Quick query on Multiwall Polycarbonate sheets for doing a garden area lean to, about 5m x 4m on a wooden frame. It comes in thicknesses of 4, 6, 10, 16, and 25mm. The suppliers suggest 4 & 6mm for greenhouse type applications, and 10mm+ for carport roofs and the like.

    Assuming they are secured correctly as recommended (bars on the joints, fixing buttons on cross members and intermediate rafters, etc.), will be carrying no weight/load , why would it not be recommended to use 4 or 6mm for a lean to roof? They're a good bit cheaper, etc.

    Your roif will have a load on it. Never forget the weight of snow


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    #13
    2012paddy2012
    Registered Users Posts: 2,880 ✭✭✭2012paddy2012


    spockety wrote: »
    Quick query on Multiwall Polycarbonate sheets for doing a garden area lean to, about 5m x 4m on a wooden frame. It comes in thicknesses of 4, 6, 10, 16, and 25mm. The suppliers suggest 4 & 6mm for greenhouse type applications, and 10mm+ for carport roofs and the like.

    Assuming they are secured correctly as recommended (bars on the joints, fixing buttons on cross members and intermediate rafters, etc.), will be carrying no weight/load , why would it not be recommended to use 4 or 6mm for a lean to roof? They're a good bit cheaper, etc.

    Did you use this ? How did you get on ? Can you cut it? Is fixing to batons handy enough thks
    Thinking of covering over side entrance with it / thanks


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