I built a folding dog gate to stop our labradoodle from walking on the carpet when her paws are muddy. It’s based on one my wife saw on Pinterest, but this specific design is mine.
I modeled it in SketchUp first to make sure that I had the hinge layout correct. I wanted it to rest against the first railing baluster but still fold up without extending past the edge of the first stair. This is why there’s a short panel against the wall; otherwise, the folded-up gate would extend 10.5″ outwards from the middle of the first stair instead of 10.5″ from the back of the first stair.
I built it out of red oak, using bridle joints for the panel frame corners and square tenons in round holes for the balusters. (Square tenons are easy to make on the table saw, and round holes are easy to make on the drill press. Round tenons or square holes are both very difficult with the tools I have.)
I ended up painting it white, but I originally thought I might stain it, which is part of the reason I used oak. The other reason is that it will likely get banged around quite a bit, so a softer paint-friendly wood like poplar would show more dents and dings.
The location where I wanted to mount the gate didn’t line up with a stud, so I made two brackets out of oak that screw into the two nearest studs, and then the gate is attached to those brackets.
I’m happy with the end result, but I’m curious to see whether the hinges are able to withstand the weight of the gate without sagging.
If you want to make your own, you can download the SketchUp plans I made. Your gate may need to be a different width based on your stairway width.