We want our mattress low to the ground so if our daughter ever falls out of bed, she doesn't have far to go. We learned the trick of putting the family bed on the ground from Christy's parents, and wanted to give it a try. However, the floor in our bedroom is uninsulated, and putting a mattress directly against a cold floor is a great way to grow mold. This frame raises the mattress 1.5 inches; just enough to ensure airflow.
Step 1: Build the Framing With Furring Strips
I measured my mattress, then cut all the furring strips to the proper length with a chop saw.
Step 2: Layout and Nail the Frame Together
Note that if you only put one nail at each intersection, the whole thing can rack like a giant pair of scissors or a folding trellis.
Step 3: Attach Felt Feet
Step 4: Mattress on the Frame
Here's Corvidae climbing off the side of the bed. When she manages to go head-first instead of her usual feet-first or hands-first, the resulting bump only requires some brief comforting, not x-rays. We often put blankets and pillows around the edge of the bed for an even softer landing. She can also crawl into the bed by herself and fall asleep.