Check out this deck

What do you all think about this deck? It was about 30-35 feet up.

I like how the braces were a much-later afterthought. You can tell by how weathered the rest of the deck is and by the fact that the neighbors’ decks don’t have them.

The sway brace (between the two posts) is installed incorrectly. A rectangle can simply turn into a parallelogram. It should have been installed at a diagonal as well (like the other two braces) instead of perpendicular to the posts.

How high should residential decks be? I mean did you notice that the posts are actually 2 posts lag bolted together about halfway up? The decking is not diagonal shouldn’t there be support under the joists to prevent twisting. Also there was carpenter bee damage to the posts.

Tall 4"x 4" posts twist under load and 4"x 4" posts, even when treated, decay below grade too quickly. In all but the lowest of decks, deck posts should be at least 6"x 6", and be no higher than 12 feet; 14 feet is acceptable if cross-bracing is used.

I’ve done a lot of research on deck collapses. They almost never collapse because of post failure. Most deck collapses occur due to sway ripping the deck of the band of the house.

So what would you report about this deck?

I suggest you CYA. I’d use the word “unsafe.” You can go on to explain that the sway brace is installed improperly as per my post #2 at a minimum, and that the posts may not be large enough for their height.

I’d also be concerned how the ledger board is attached to the building, how the band joist is attached to the post(s), and if all joist hangers were properly attached with the correct fasteners.


The post appears to be scabbed together about 3/4 of the way up. That would make a great hinge.
I agree with Nick and would recommend an SE to further evaluate. That looks like an accident waiting to happen.

That deck is a disaster waiting to happen…!
6x6 posts would be a minimum and their connections between joining members are a critical issue as well.
I’m not familiar with any dimensional lumber that comes in at 35’ lengths. Diagonal bracing on the outboard posts with steel plates utilizing hillside washers and threaded rods would also be in order.
The existing posts appear to be deflecting… Nice! Recommend contacting a structural engineer and make absolutely clear the obvious safety hazard this represents.