You will need a piece of plywood, 2 4x4s, 2 2x4s, T brackets, screws and nails. You will also need two Expedit bookcases. My husband began by building the base out of 4×4 posts and 2×4’s to brace between them. The height of the 4×4 posts was just a bit taller than the bookcases that were going to be slid next to them. Cut a piece of plywood just an inch or two smaller than your mattress. Center the plywood on top of your base and attach it with nails to your 4×4 posts.
After the base was complete, I wrapped black felt across the top of the plywood and wrapped it under to cover the bottom of the plywood as well. I used a staple gun to keep it in place. This will protect your mattress and also the bookcases you will slide under it.
The next step is to simply slide your Expedit bookcases under your plywood. The base plus the bookcases really makes the bed quite sturdy. We used a full size mattress on our platform bed, but I’m sure you could adjust this to fit a queen or twin (with one bookcase) as well.