Make the Frame
For a seamless look, build bench out of existing decking material. Build bench to fit existing deck space or use as barrier at side of low deck.
Start by cutting frame from 2x4s.
With circular saw, cut two long boards for frame sides and six cross pieces.
Sand edges smooth.
When positioning center crosspieces, leave room for center legs between them, if bench is 8 feet long.
Pre-drill and screw together frame.
Frame should be four inches shorter than length of seat and four inches narrower than width of seat. Standard bench width is 16 inches.