The IRC prescriptive deck guide calls for decks taller than 6' to have diagonal bracing placed parallel (planar) to the beam from post to beam.

My deck, which is built with a beam on one side and a house-anchored ledger-board on the other, with joists running perpendicular to the ledger/beam, currently has this diagonal bracing running from beam to post. However, I am planning on screening in the underside of my deck and do not want the bracing there. I am looking for alternatives. I was told that I could run the deck boards diagonally instead, but my deck surface is already in place and I do not want to redeck the entire structure.

Are there other alternatives, such as a prefabricated bracket I could buy to replace the bracing?

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    If it's a diagonal brace running from post to beam, it won't be parallel to the beam. ;-) The reason for the angled brace is that it forms a triangular structure in the same plane, which is very stable and will prevent the the tall posts from tipping. This means you need at least one diagonal brace on each side of each plane (each vertical face of the deck). I'm pretty sure I don't believe that diagonally-arranged decking would stabilize the uprights, because that would only reinforce the shape of the top of the deck (one plane). – Craig Jun 11 '15 at 7:07
  • The diagonal bracing is there for a reason. Leave it in place. – Michael Karas Jun 11 '15 at 9:59
  • @Craig Bracing from post to beam is parallel to the beam. Bracing from post to joist is perpendicular to the beam, but is optional in a house-supported deck according to the prescriptive guide. – David Pfeffer Jun 11 '15 at 11:50
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    Well that definitely makes sense. If it's attached to the house, then the house itself is stabilizing the sides of the deck. That still wouldn't keep it from tipping/twisting to the sides, but the diagonal deck planks would accomplish that, because the top rectangular frame of the deck would not be able to deform. Your original post didn't specify attaching the back edge of the deck to the house. – Craig Jun 11 '15 at 18:39
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    Hi David, I agree that "unstable" is a matter of definition within a set of requirements. If whatever you do, doesn't stiffen the deck up enough that it can't easily be deformed into a rhombus, then it just won't be safe. You know what, though? I wonder if you could put diagonals flat across the bottoms of the joists? – Craig Jun 11 '15 at 21:08

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