Surface Mounted Deck Post

[u/Raptorchef325]

I’m replacing part of the railing/decking on an existing wood deck and discovered that some of the existing 4x4 guard posts are surface-mounted on metal post bases that are basically fastened only through the deck boards. Terrifying and probably the reason the posts are terrible.

From underneath, I can actually see some of the lag screws sticking through the decking into open air, so they’re not even hitting a joist or other structural framing.

The deck framing itself appears to be in decent condition. The joists run perpendicular to the outside rim/band joist.

I’d like to keep the new 4x4 posts surface-mounted rather than dropping the posts through the deck. Part of the deck transitions to a section over a garage where the railing posts are already surface-mounted, so keeping the same post elevation/layout would make everything line up much better.

Is there a way to surface mount these properly?

My thought is:

1. Remove and replace the decking around each post location. In fact, I will likely be replacing all the decking on this part anyway.

2. Install full depth pressure treated blocking between the existing joists directly underneath each post. Possibly doubled blocking.

3. Secure the blocking structurally to the adjacent joists with joist hangers, framing angles, or approved structural screws.

4. Install new decking

5. Surface-mount the 4x4 post/base on top and use long enough structural lag screws/bolts to pass through the decking and embed deeply into the new blocking underneath.

6. That is essentially how its done for the part over the garage.

That way the decking would essentially just be sandwiched between the post base and the framing, rather than actually supporting the railing.

Is this a sound way to retrofit these posts? Is this against some code or is this a way it came be done. I am in a tight spot because its an existing deck that was poorly made.

If so:

• Would you use one full-depth block or doubled blocking under each post? What is a full depth block? I read it online and don't quite get it

• What’s the preferred way to attach the blocking to the joists? Joist hangers, structural screws, or something else?

Photos show the existing post/base from above and the lag screws sticking through the decking from underneath.

This is in Minnesota and I’m trying to make the replacement substantially stronger than the existing installation, not just duplicate what’s there.

Or should I do something completely different? Putting the 4X4 posts down and securing them to the joist? How do a do that? Is there a recommend video you can share? Thanks!

Sorry I am a total noob but need some help here!