How to Reinforce a Platform Bed for a Waterbed Mattress

Make the Support System

• 1

  Create two center support pieces and two support tees for the middle of the platform bed frame using 2-by-10 lumber if the frame does not have drawers. If the frame of the platform bed is taller than 9¼ inches, you can use 2-by-12 lumber. The center support pieces should be 12 inches shorter than the length of the bed frame. The support tees should be 12 inches shorter than the width of the bed frame.

• 2

  Measure and mark 1/3 of the way in from each end of the cut support pieces. Then cut out a rectangle that measures 1½ inches wide and 4.6 inches deep at each of the marks you made. If you are not using 2-by-10 lumber, the depth of the cuts should equal half the depth of the board. Repeat this process with the two support tees.

• 3

  Place the two center support pieces next to each other on the floor, in the location that you want the waterbed. Then place the support tees into the center support pieces so the notch you cut out of the tees fit into the notches you cut out of the support pieces.

• 4

  Place the platform bed frame over the center support pieces and tees. The platform bed frame is now the waterbed pedestal.

Build the Waterbed Deck

• 5

  Cut two sheets of OSB to size. The size that you need to cut the board depends on the size of waterbed you want. For a king bed, cut the board so it measures 6-by-7-feet. Cut the board 5-by-7-feet for a queen bed. For a super-single bed, cut the board so it measures 4-by-7-feet.

• 6

  Secure the two sheets of OSB together with wood glue and use clamps to hold the sheets together. Allow the glue to fully dry.

• 7

  Secure the glued OSB to the board of top of the waterbed platform with 1¼-inch wood screws, making sure the boards are centered. Space the screws 6 inches apart. Do not remove the existing platform from the old platform bed frame, because it will help provide extra support for the waterbed.

Build the Waterbed Frame

• 8

  Cut two lengths of 2-by-10 lumber so they measure 7 feet. These pieces are for the sides of the frame.

• 9

  Cut two lengths of 2-by-10 lumber for the head and foot of the bed. The lengths of these boards should measure the width of the waterbed platform plus 2 1/8 inches.

• 10

  Rabbet the bottom ends of the boards for the head and foot of the bed by ½ inch. Use a router and a ½-inch rabbet bit to complete this task.

• 11

  Lay out the lengths of lumber so the sideboards are between the boards for the head and the foot of the bed.

• 12

  Secure the lengths of wood together using two 3-by-¾-inch L-brackets at each joint, on the inside of the frame. You should place a bracket along the upper and lower portion of each joint. Use wood screws to secure the brackets to the lumber.

• 13

  Secure the frame you just built to the waterbed platform using more L-brackets. Equally space two brackets at the head and foot of the bed frame, and four brackets along the sides of the bed frame.