Framing joists have developed a curve.

[rodav]

Hi,
I'm currently building a deck in Brisbane Australia.
The 2 longer framing joists have developed a curve since I built the frame.
Probably because for the last month, Brisbane has had alternating rain and sunny 30-37c heat (about 95-100f).
They were straight when I built the frame.

The curve in the drawing is exaggerated, it's about an inch over the 7.2 MTR length.
The drawing shows the frame and joists. There's actually 15 joists not 7 as in the drawing.

I'm unsure how to deal with this, I've never built a deck before and have only made small scale hobby projects like a desk, bookshelves etc.

The only solution I can think of is screwing some tapered timber to the outside of the frame to compensate and give it a straight edge.

I appreciate any suggestions.

 

[foxhole]

No noggings? You have nothing there preventing it moving.No diagonals.
Not that a slight curve will be very noticeable , fix you decking board and cut that straight .
How is it fixed to ground .?

 

[rodav]

It's just a hand drawn picture to explain the curve. It is not an accurate representation, it's just to explain where the curve has occurred. I haven't put any details in the drawing because I'm just after advice about the curve.

I have just finished installing the joists.
All that has been built is the frame and the joists. The deck frame is not completed. It has developed the curve during the building of it.

 

[robinbanks]

Pull it straight with a side on timber (or push/pull it; if the corners are secure, park a car against it/rope pulling on it or similar) while you get the deck boards screwed down. Once they're on it won't go anywhere

Note: stagger your deck board joints. It will bend if you eg had every board joint landing on the same joist

 

[rodav]

@robinbanks
That's a good idea. I can't get a car into my back yard but I can jam a piece of wood in between the side of the house and the frame joist.
The deck board joints will be staggered anyway because I saved money by buying random lengths.
Thanks

 

[robinbanks]

You'll probably find it won't take much to flex it and get it bent to shape.. I've just often found the car a handy heavy thing to move into some place and rope/ratchet strap something to, to hold it while I do something else!

 

[rodav]

@robinbanks
I made sure the corners opposite the curved side were secure and just jammed a piece of wood between the house and the curved side. Because it had to push all the joists through to the other side, I thought that it would require a lot of force, but like you said, it actually didn't take much. All up it took me about 10 minutes to straighten it.
I've now finished the deck,
Thanks again for your advice.