The Frame

• 1). Measure your child's mattress. These measurements, plus a half-inch on each side, will dictate the size of the platform bed frame you'll construct.
  
  
• 2). Ask your local hardware store to cut wood for you. Based on the mattress measurements, have the pieces for a rectangular frame cut out of 3/8-inch-thick plywood. You'll need two shorter pieces for the top and bottom ends, two longer pieces for the left and right sides and one large rectangular piece for the top, where the mattress will rest. You'll also need two two-inch-wide pieces that are an inch shorter than your left- and right-side pieces. These are rails for the top piece to rest on.
  
  
• 3). Decide the height of your platform bed frame based on how high you want the bed to be off the ground. If you're making a bed for a young child, keep it low, because he or she might fall out.
  
  
• 4). Mark with your pencil two inches down on the inside and the outside of your side frame pieces. Using these marks, screw the two-inch-wide wooden rails to the inside of the side frame pieces. Use five screws for each rail. Space them out evenly.
  
  
• 5). Screw the frame together. Use three screws on each side.
  
  
• 6). Put your top plywood piece on top of your rails. You can see that it's slightly inset, which will let the mattress fit snugly into the frame. Attach it to the rails with two screws on each side.
  
  

Upholstering

• 1). Fold the cotton batting in half, creating a double thickness. Cut strips to fit around the sides of your frame. Leave room to overlap it at the top and bottom of the frame, so you can fold it over the top and bottom.
  
  
• 2). Fold the batting over the top and bottom of the frame. Pull it snug against the frame and staple it down.
  
  
• 3). Cut strips of fabric the same size as the strips of batting. Starting on the bottom of the frame, fold the fabric over the edge of the frame and staple it over the batting. When you reach the end of a strip, fold its end over so the raw edge is hidden, and put the next strip's raw edge under this finished strip. Pull the two strips taut over the frame and staple them over the batting. When you finish the bottom of the frame, turn the bed over. Fold the fabric over the top edge of the frame and staple it over the batting. Treat the raw ends of each strip in the same way you did on the bottom.
  
  
• 4). Fold the fabric at the corners so it lies flat and staple it tightly.
  
  
• 5). Put the mattress on top of your upholstered frame. You have just constructed a child's bed.