Fixing timber joists to shipping container roof.

[woodman-46]

Hi,
I want to fit a shallow incline roof onto my shipping container worshop. I am going to fit joists about every foot spacing going back to the back edge from the front. These will be gradually reducing thickness to achieve the sIlope . I need to fix these to the roof and had thought of using heavy duty toggle bolts. Basically drill holes on the raised up ribs of the container lined up with holes in the joists push a toggle bolt through and tighten up. Should this be a good method ?
Although the container roof itself would be covered by the new sloped roof I was going to put a rubber washer between the joist and container to for a good deal around hole.
If you don't think this is a good idea can you advise me of better method please
By the way I would use toggle bolts because the container is lined inside and therefore the holes in roof would in effect be blind.
Thanks

 

[HERTS P&D]

Is the roof completely flat? Is it waterproof? What happens when it rains, does the water run off?

Any pictures?

Andy

 

[Notch7]

I wouldve thought TEK screws would hold well

 

[woodman-46]

Thanks for your replies. The roof is flat but, as mentioned, with raised up ribs. It seems waterproof but is definitely showing signs of rust and wear hence the need to fit the roof to prevent future leaking.

 

[HERTS P&D]

You could just clean the roof and fibre-glass it.

Andy

 

[opps]

Perhaps consider using Owatrol oil or Owatrol marine oil to coat the rust

Marine Oil | Rust Inhibitor & Paint Conditioner | Owatrol Direct

A powerful marine rust inhibitor which penetrates through rusted surfaces to isolate sound metal below & oil-based paint conditioner which improves flow.

www.owatroldirect.co.uk

and then just paint the roof.