Is it normal for an elevated deck to sway slightly when someone walks on it?

Replacing those posts with proper concrete footings and adding **Y-bracing** is almost always the right move for an elevated deck that's started to drift. If your posts are currently sitting in or on dirt, they're likely rotting at the base or shifting with the ground moisture, which is why you're seeing those gaps. You don't need a $30k rebuild if the joists and decking boards are still solid and the ledger is secure. The secret to doing this yourself without the deck collapsing is using **temporary supports**. You’ll want to rent or buy a couple of heavy-duty bottle jacks. You basically build a temporary wall or use 4x4 posts on jacks to take the weight off the specific section you’re working on. Once the weight is safely off the original post, you can cut it out, dig a proper hole—make sure you're below the frost line for your area—and pour a concrete pier with a galvanized post base.

To get the deck plumb again before you bolt everything down, a come-along or a heavy-duty ratchet strap is your best friend. Hook one end to the deck frame and the other to a solid anchor point like a large tree or even a truck hitch. Slowly crank it until the structure is square and vertical. You'll want to keep it under tension while you install those diagonal braces to lock the position in place.

Use **6x6 posts** for the new supports if you can, as they provide much more surface area for those Y-braces to bite into. And don't just use standard wood screws; go for galvanized carriage bolts or heavy-duty structural screws to tie the braces into the posts and the rim joist. That’s what actually stops the swaying. The difference in stability is night and day once those triangles are locked in. It’s a lot of physical labor and you’ll be sore for a week, but the actual mechanics of the fix aren't that complex. As long as the wood isn't crumbling from rot where it meets the house, you're looking at a few hundred bucks in lumber and concrete versus that total replacement quote. It's a solid long-term fix, not just a band-aid, provided your footers are deep enough.

If you're going thru all that trouble with the 6x6s, don't just use standard lag bolts. Get yourself some Simpson Strong-Tie SDWS Structural Wood Screws for those Y-braces. I used them when I beefed up my own deck last summer and the lateral stability is night and day. They bite hard and won't snap under pressure like the cheap stuff at the big box stores. Plus, you won't need to pre-drill every single hole wich saves a ton of time when you're working overhead. It’s the best way to make sure that $30k repair quote stays a distant memory.

Make sure you check the ledger board while you're under there. When mine started leaning, it actually pulled the ledger a fraction of an inch away from the house siding. I didn't just brace the posts; I installed those DTT2Z tension ties to pull the deck frame back tight against the house joists. It stopped that "springy" feeling imediately.

Also, if you're digging those footers, rent a power auger from the local hardware store. My back was trashed after trying to dig the first hole by hand trough heavy clay.

Update: I took a closer look at the ledger board like suggested and found a small gap, so I’m definitly grabbing those DTT2Z tension ties. I’m also picking up the structural screws for the Y-braces. Quick question—if the joist wood feels a bit soft where the screws need to go, will those still bite well enugh, or do I need to sister the joists first?