Measure the dimensions of your washer all the way around. As an example, assume the washer is a perfect square and each side measures 30 inches. Cut a piece of plywood 30-by-30 inches to serve as the top of the base.
Cut two pieces of plywood into a rectangular shape. The length is the same as the width of your washer, which is 30 inches in the example. The width should be the height you want the pedestal to stand. A pedestal or stand from the store typically stands around 15 inches tall.
Cut six 2-by-4 pieces of lumber. Cut two of them 2 inches shorter than the length of the washer, which in the example requires 28-inch pieces. The four legs should be 2 inches less than the height of your stand, which is 13 inches in the example. The shortened length accounts for the thickness of the plywood to ensure all pieces of wood fit together properly.
Place two of the legs, the 13-inch pieces, under one of the 28-inch pieces to form one side of the base. Hold it together with 3-inch nails or screws, depending on the equipment available to you.
Repeat the step for the other side of the base with the other two legs and side.
Nail or screw the larger piece of plywood to the top of the base, then nail or screw the other two pieces to the sides of the base.
Paint or stain the wood to match the design and decoration of your laundry room.