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Building Roof UNDER Front Deck?

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  1. #1
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    Default Building Roof UNDER Front Deck?

    At the front of our house, there is a small raised balcony 2m deep and about 6m wide. It runs from the front door to a corner of the house. Standard deck/joists construction.

    When it rains, no matter the angle, the water of course runs right through to the ground below...particularly annoying as it soaks up the front door mat and provides no protection for anything out the front.

    I'm looking for some assistance in how I might fix something to drain the water away...cosmetically I'm keen to make it look flat surface from beneath.

    IN the US I have seen http://www.underdeck.com/ and http://www.undercoversystems.com/howitworks.html as examples of what I am trying to do.

    Thanks,
    Julian

  2. #2
    Rigid Member UteMad's Avatar
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    Default

    Was waiting for someone to reply for you but noone did!

    Nothing available is Aus as far as i am aware ... The US has sails that clip between the joists aswell... Your only choice is to fit battens underneath to give runoff and fit roofing screwed up to it .. Not really the best thing for your structure as it will trap rubbish .. Or compressed fibro and tile the deck then fit your ceiling you want

    cheers utemad

  3. #3
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    Default Thanks

    Thanks Utemad....great to have some input, I too was waiting for a flurry of replies!

    Your thoughts on the battens, would these be like "blocks" of wood at various measured heights, or would I be better to run a wedge shape the entire length?

    Let me know if you think a picture will tell a thousand words, and I can post something up to show the area of concern.

    Julian

    (edit: I'm not too worried about the rubbish aspect, there are no trees in the area that would drop leaf litter, so nothing significant in that regard)

  4. #4
    Rigid Member UteMad's Avatar
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    Hi MAte

    You have to run battens the width of the deck ... The first batten closest to the house would be say 35mm thick (70x35) the next batten 70mm thick ( 70x45 ) and the next batten say (90 x 45 ) this will give you some run off when you screw thw sheets up to the underside...

    The problem is if the joists sit on a front bearer its near impossible to get the water out past it..

    Post a pic if you like and i could comment further.. Keep in mind it will never be as good as a roof screwed from the top side as all the gaskets on the screws are under the sheet and not on top like normal


    cheers utemad

  5. #5
    Senior Member brynk's Avatar
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    it will be extremely difficult to shape the battens to give the fall you desire. you really need to use packers between the battens and the underside of the joists. they would have to be fixed off length-wise in the direction of the drainage to lessen their tendency to trap water.

    as utemad has pointed out, it will turn into a wonderfully expensive shyte-trap. just thinkin about it, you would be better off using what is called a top-hat section as your 'battens', fibrous-cement sheet painted both sides as your cladding. these would be screw-fixed into the battens, each sheet being attached to one leg of the top-hat. the legs have polyurethane sealant applied before the sheet is attached to ensure there is not leakage where the sheets join. between each sheet there is also polyurethane seal applied. it seems like a root, but this method of construction allows for the movement in the individual f/c sheets to avoid the ugly and (in your case) purpose-defeating cracking occur in the corners of the sheets - re, mackellar soccer club in canberra.

    if it is done properly, the sheets could be removed once every 10 years or so you clean the crap out and re-paint them before you put em up again. some considerations that come to mind - the sheets would need to be ripped in half so they are only 600 wide, less span = less flex & less load on the screws & top-hats. less surface-area = less overall movement resolving itself at the battens. you would need to use polyurethane sealant as silicon is an acetic cure, which will hasten the demise of your gal steel.


    r's brynk
    "Man got the opposable thumb - woman got four opposable fingers." - Rowdy

  6. #6
    Senior Member brynk's Avatar
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    i just read my post - here is a picture
    Attached Thumbnails Attached Thumbnails top-hat-cfc-sheet.jpeg  
    "Man got the opposable thumb - woman got four opposable fingers." - Rowdy

  7. #7
    Senior Member brynk's Avatar
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    how much head space do you have? you could overlap the sheets but leave a height gap between them so the wind could do your cleany-work for you - sortof like upside down tiles without any tiles.

    you could sit there and admire your handy work over a beer or ten, until you got the opposite of vertigo... horizontigo
    "Man got the opposable thumb - woman got four opposable fingers." - Rowdy

  8. #8
    Resigned SilentButDeadly's Avatar
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    Julian.....I'm assuming here that the joists run at right angles to the house....and that your bearers sit under the joists. If so there might be an issue. If your bearers and joist are in the same plane that'd be a great deal easier...

    You can use colorbond sheeting as your underdeck roof. It is available in either a flat sheet (cut to length) or it can be very faintly profiled (looks like coolroom panelling).

    Run it parallel to the house (across the joists) so water falls across the sheets rather than down. Fit using Buildex Type 17 wafer head screws. Create a fall away from the house (along the joists?) using 10x10x1.5 galvanised square tube with a spacer at the outer edge and middle while house end is fixed to the verandah structure.
    Joined RF in 2006...Resigned in 2020.

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