I usually bolt my guard posts to the outside face of the rim joist to maximize a deck’s usable square footage. This presents a problem at the corners, though, where there is no place to fasten the post. Most builders solve the problem by installing double-post corners, which I think looks clunky. Instead, I extend the rim joist beyond where it intersects with the end joist, so that I can place the single corner post where it needs to go. I reinforce the connection with metal hardware, as shown in the drawing below.
Gary Peniston
In my area, Simpson Strong-Tie DTT2 tension ties (or the equivalent) are required to connect all rail posts to the deck framing. In this application, the DTT2 on the corner post strengthens the post in one direction at the base, while the top rail – which locks the assembly together with the other guard posts – strengthens it from side to side at the top.
Gary Peniston
A short section of fascia with an acute angle cut covers the metal hardware that connects the corner post to the extended rim joist.
Gary Peniston
The corner is finished with a triangular wedge of decking.
Because this leaves a big piece of metal hardware exposed for all to see, I run the outermost course of decking beyond the last joist, so that it extends to the outer edge of the corner post. Then I cut a triangular-shaped piece of infill decking to fill in the corner, as shown (see photo). Finally, I cut a tapered section of fascia that boxes in the metal hardware and conceals it from view.