Whenever I need a scaffold of modest height, I use the jacks shown in the drawing. They’re easy to construct, don’t cost much and they’ve never failed me.
The jacks are held in place by clear 2×4 braces that angle up from grade. Braces to the ground should be staked. If you’re working off a subfloor, a nailed-down cleat will securely hold a brace.
The jacks are made from 2x4s and -in. plywood. The horizontal leg should be about 32 in. long, while the vertical one should be about 45 in. long. For added safety, I glue and nail the gussets to the legs. 1 use a 2 x12 plank on top of the jacks, and I’ve used them in series with lots of jacks and planks to handle long runs.
Dave Blom, Bellingham, WA