I have a roof over my deck. The posts that support the roof are attached to the deck via simpson timber screws (as seen in the photo below). Is there a better method or bracket I could utilize to beef up this connection?

Post attachment to deck

  • What's hiding behind the plywood that those screws go into? Are they only into the rim joist or is there another post inside there? As Michael Karas♦ noted in his answer, if it's just the rim joist, pressure (from wind, snow load, or a strong physical bump makes that post a long lever that could twist the rim joist away from its connections.
    – FreeMan
    Nov 16, 2021 at 13:09
  • That post can't be a lever. It's securely fastened to a roof structure which is inherently diagonally braced. You'd have to blast it loose first. The only issue here (if anything) is shear sag.
    – isherwood
    Nov 16, 2021 at 13:51
  • Assuming that the framing to which the posts attach is adequate, my only concern here is sag due to wood deformity around the screws where the post and the rim sheathing interface. I'd put a mark under the post to see if anything moves. If it does, some steel bracketry would be in order.
    – isherwood
    Nov 16, 2021 at 14:01
  • yeah, fair point on the anti-shear inherent in the roof sheathing, @isherwood. I hadn't had coffee yet when I posted that.
    – FreeMan
    Nov 16, 2021 at 15:55

1 Answer 1


Use of long carriage headed bolts fitted into holes that are bored all the way through the post and also through the deck joist underneath will be a stronger connection. If bolts of 1/2" diameter are used (2 or 3 bolts depending upon the width of the deck joist) with flat washers and hex nuts they can be tightened a lot and be stronger than those two screws.

One thing to consider is if the deck joist itself is sturdy enough. We cannot see it in your picture but the tall post can act as a very long lever arm and the deck joist could easily be twisted. One way help to reduce the movement of the post side to side is to add additional angle braces from above down to the posts.

  • 1
    Those Simpson timber screws are designed, spec'd and listed to be replacements for carriage/lag bolts, so there's no real need to consider replacing the existing screws. Adding another one or two "because it feels better" wouldn't hurt. I agree with the concern about what it's actually attached to behind that plywood.
    – FreeMan
    Nov 16, 2021 at 13:06

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