What can I use for bed frame supports when building a platform bed frame?

You will need bed frame supports, if you are building your own platform bed frame. Usually, these supports are created using either 2x4 boards or 2x8 boards, inside the wooden box, running either horizontally or vertically, and screwed into place inside the box. Supports hold the mattress flat and firm, and keep it from sagging on the platform. A platform is built the size of the mattress or a bit larger, with a flat piece of wood creating the actual platform. This is supported by a wooden box frame, built in a rectangle or square. Inside this frame you need supports to hold the platform.