Garage Roof Replacing

Discussion in 'Builders' Talk' started by Bozzy, Apr 24, 2017.

  1. SWBUILDERS

    SWBUILDERS Active Member

    4.3m clear span bit much for 6 x 2 mate? I think that's on the limit of 8 x 2 @ 400 for flat roofs with no more loading than its own weight and maintenance
     
  2. Jord86

    Jord86 Screwfix Select

    9ft i read it at.... or again am I blind and missing something? :confused:
     
  3. Bozzy

    Bozzy New Member

    Width of garage (span) is 9ft (or 2.74M)

    Regards
    Bozzy
     
  4. Jord86

    Jord86 Screwfix Select

    Then I would say 6x2 is fine for your garage roof mate.
     
  5. SWBUILDERS

    SWBUILDERS Active Member

    Yeah that's
    sorry my bad Jord 6 x 2 will be fine for 2.7 m span nearly cost you a few quid in timber there dunno 14 foot from somewhere should pay attention lol
     
  6. Jord86

    Jord86 Screwfix Select

    No worries mate, :) makes a change, it's usually my maths that chronically embarrasses me!
     
  7. SWBUILDERS

    SWBUILDERS Active Member

    Ha:p yeah been a long day
     
  8. Bozzy

    Bozzy New Member

    Thanks again for the replies.

    As a happy medium, would it be OK to go for 500mm spacing?

    Also, to keep the weight down a bit more, would it be acceptable to go down to 11mm or 8mm OSB3 (non T&G)?

    Regards
    Bozzy
     
  9. jonathanc

    jonathanc Guest

    Why not use box profile steel sheet? Fairly light, get the length you want and easy to fit?
     
  10. SWBUILDERS

    SWBUILDERS Active Member

    18 mm really mate 11mm or 9mm is too flimsy

    Spacing at 400 or 600 allows you to catch ends of osb boards which are 1220 x 2440
     
    Bozzy likes this.
  11. Jord86

    Jord86 Screwfix Select

    You can use 500centres, but you'll either have to cut every sheet if you use square edged Osb, or use t+g. No, not acceptable at all to use 11 or 8mm, nowhere near thick enough I'm afraid.
     
    Bozzy likes this.
  12. Bozzy

    Bozzy New Member

    Hmmm

    Just been googling box profile steel sheet, found a supplier that does them in 2.8M lengths and Polyester coated, these would fit nice and have 50mm overhang for the gutter, thoughts on this please?

    Regards
    Bozzy
     
  13. Jord86

    Jord86 Screwfix Select

    Quicker, cheaper and lighter than all that's been previously discussed. Doesn't look as good in my opinion but then again it's a garage flat roof, what more do you want?
     
  14. Bozzy

    Bozzy New Member

    Yup, quicker, cheaper and lighter, black coated polyester will still look better than the moss ridden mess I have.

    Anyway, still not sure of 1 question still.

    As the roof is sloped (LH side wall is 2 bricks higher than RH wall), how should I seat the joists in the hangers (or on the brick), do I install wedges or trim the ends of the joists (to create a flat bottom for the joist angle)?

    Below image is what I mean, ie, how should I deal with the joist gaps, cut the joists to suite or make some wedges so that the angled joists sit flat?

    [​IMG]

    Regards
    Bozzy
     
  15. Bozzy

    Bozzy New Member

    OK

    I have done a lot of googling and seen literally hundreds of reports of condensation issues with a cold steel roof, so back to the idea of OSB3 @18mm.

    1220 X 2440 sheets would result in a lot of wasted timber, so looking at 2400 X 600 sheets T&G which I can source locally, below is a cad knock-up of the layout which is to scale.

    Red is the exterior outline of the brick garage, the vertical darker strips are the joists spaced at 600mm as suggested which do capture the vertical joints very well, then the 2400 X 600 OSB sheets are shown. a bit of jigging about to get everything in place, but hopefully this will do it?

    This is showing the sheets without cutting or trimming, so plenty to cut off from the left to fill the 2 voids on the right.

    [​IMG]


    So after a suggestion on here, I am now seriously considering Fibreglass covering now, any other views or comments please?

    Also, still not sure about the seating of the joists at an angle?

    Regards
    Bozzy
     
  16. SWBUILDERS

    SWBUILDERS Active Member

    Hi, I'm a fan of Fiber glass roofs have done lots of them and seems the best material in terms of maintenance and longevity, as for the seat cuts all you need to is plumb a line with a level were the joists hits wall plate inside of brick wall that is highest and then measure up that line how far the joists are off the wall plate (say 30mm for instance) and mark a line 90 degrees off your plumb line repeat for other side but off the external side of brick work and then the joists will sit flat it's called a birds mouth but will be a mini one as your pitch is so low if your garage is square you can cut one and use as a template for the rest and cut them all on the ground and lift them on
     
    Bozzy likes this.
  17. 2shortplanks

    2shortplanks Active Member

    Corrugated steel would be my thought too. You can get it in lengths up to 9m, plastic coated in various colours, also with an anti-condensation layer, or insulated. Probably cheaper than adding timber supports,osb etc, and quick. Cladco was the supplier I used for my shed roof, very pleased with the job.
    As far as removing the existing sheets, get youself suitable dust masks, disposable overalls, gloves and shoe covers, and seal them in a poly bag and dispose with the sheeting afterwards. Best thing is to damp the sheets down and avoid breaking/drilling. Did one recently, used bolt cutters on the fixings, lifted the sheets off, wrapped in polythene sheet taped up.
     
  18. Illio Juzygen

    Illio Juzygen New Member

    Looks like asbestos roof
     
  19. lewis jackson

    lewis jackson New Member

    It will cost to remove that, very expensive
     
  20. Bozzy

    Bozzy New Member

    As I an not getting any sense from local council (long story) I contacted a local asbestos removal company, he quoted £225 to take the sheets away, or £300 to remove and dispose of the roof.

    Don't think I'll bother removing it myself now as I think £300 sounds fair.
     

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