Flat Roof Garage? Advice needed

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Hi All


Am sure this topic has been covered before, but I would appreciate some advice/confirmation that I am on the right track.  Am building a sloping flat roof garage:


1. 5.4m C16 225x75mm joists, each end to sit on inner half of flat laid block, with 400mm centres, running the width of the garage

2. To acquire 1:60 fall perpendicular to the joist,  I am intending to screw fillets (rough sawn/75mm width) on top of each joist in declining heights to allow for fall to rear

3. Also x3 lengths of noggins to support joists

4. Cover joist/fillets with OSB3 - was thinking T&G to allow for fact no level noggins to help support.


Hope this makes sense? Would welcome comments before I make a Charlie of myself!  Thanks in advance.


Best Dave

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Furring strips are fine. I used 3" difference in course height across 3.6m garage so no strips needed there but horses for courses. You may struggle to get t and g osb at sensible money depending on local stockists. You'd only need 4 rows of noggins to catch all joints on square edge. 

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Hiya Oz07


Thanks for comments. 


NB - Am not able to use sloping firrings as these would have to follow the slope which is perpendicular to the joists, so am using fillets, which raises the osb above where the noggins would be.  This would be the reason why I suggested T&G - but 8x4 sheets are much cheaper as you mention


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