Roof strapping - deck

[Chief012]

Hi all,

I have a question regarding gal strapping for a roof above a deck. The decks roof is attached to the house along one of its longer sides, and will shortly have a polycarbonate roof fixed to it. My question, before I fit the roof is, do I need to strap the roof from corner to corner. And if so does the strapping need to be cut into the rafters (like on wall strapping), or can it simply be a flat strap clouted down onto the beams?

Thanks for your help
Cameron

[DvdHntr]

Depends on the size of the deck roof. But I would strap from corner to corner and don't forget tie downs at the post and the existing roof.

[Chief012]

Thanks for the help dvdhntr,

Its a pretty big deck 6500mm by 4000mm. Do I need to cut in through the rafters slightly and use angled strap, or is flat strap on top ok.

Thanks again

[SilentButDeadly]

Flat strap is fine but you'll need to tension it slightly. I used a wire loop through the strap holes and a ratchet tie down strap. Works a treat.

[billbeee]

Hi Cameron,
For a roof that size I'd be putting on two sets of diagonals. This is optional as I don't know what the rest of the structure is like.

Not seen flat strap for years, it's a pain in the bum. Go to a roof supply place, Stratco etc and buy "speedbrace" or whatever they call it where you are.
It comes in 6M lengths and has a shallow vee shape so that it is fairly rigid when lying on your rafters, so no need for tensioning. In the attached photo it is the stuff with all the holes in it.
Don't use clouts, use the correct strap nails. The have a thicker head than clouts.
In theory to join two together you should span two rafters.
The ends and joins should be turned down the face of the rafters with 4 nails.
The bracing starts and ends at the anchor points of your rafters, that is not at the fascia but the beam fixing.

This is how you should do it, if you don't do it according to the codes, don't bother. What's the point of wasting material if you don't do it right?

Cheers
Bill.

[silentC]

You can get a tensioner for flat strap, which is just a V shaped plate with a hole through it and a matching bolt and wing nut. Bolt goes through the strap and the plate, tighten the wing nut to tension the strap. If you need more tension over a longer length, you just put in another tensioner. We used it a lot on walls.

But yes, speed brace for the roof.

Edit: if you use strap you definitely need one on both diagonals. Speed brace only needs one because it braces in tension and compression.

[Chief012]

Excellent, thank you all for your advice. That definitely answers my questions. I definitely want to do it the right way and do it once!

Thanks again

Cameron

[billbeee]

Hang on,
Silent,
Speedbrace is pretty thin stuff. No compression strength at all!
It must go both ways.

Cheers
Bill.

[silentC]

Sorry, yes you are right. I was thinking of angle brace - the square stuff you use in walls.

[DvdHntr]

Make sure the angles for the speedbrace are between 30-60 degrees, otherwise change the configuration.

[DvdHntr]

Just one more thing. When you say it is connecting to the existing, is that a wall frame or lintel or other? Have you made sure that the existing can carry the additional load required?

[Chief012]

Ok,..where to start. First, just to confirm speed brace will run from corner to corner & corner to corner. ie two braces in total - one: L/H top to R/H bottom and second: R/H top to L/H bottom.

The deck roof structure is supported by 100mm square posts at the rear which are coach screwed to the rear of the house frame. The rafters are pryda saddle (?) bracketed to the rear of the house where possible and the others are bolted and joined to the existing rafters on the skillion roof above the rear of the house. They are also slightly checked out to sit snuggly on the frame at the top of the wall,....hope this terrible explanation makes sense!

[DvdHntr]

So you have a beam supporting the rafters which are in turn supported by the coach screwed posts into the existing frame.

[Chief012]

Yes thats right. I will also within the next year be building a room down one side of the deck which will be attached to the rafters of the deck roof as well for additional support.