Buy two lengths of PVC pipe. One should be 1 1/4-inch diameter and 10 feet long. The other should be 1-inch diameter and 10 feet long. The smaller one must fit inside the larger one.
Place the 1-by-6-by-36-inch board flat on the 6-inch side. Measure and mark the midpoint. Stand the smaller PVC pipe on end on the board centered on the midpoint mark. Place a metal L-bracket on each side of the pipe with the ends extending toward the ends of the board. Outline the brackets on the board. Remove the PVC pipe.
Drill two holes through each bracket, through the wood and out the other side. Insert a bolt through each hole. Place a washer on the end of each bolt on the other side of the board. Screw a nut on each bolt and tighten as much as possible. Now the L-brackets are fixed firmly to the board.
Replace the smaller PVC pipe between the brackets. Drill two holes through the sides of the brackets that are perpendicular to the board. The holes will go through the PVC pipe as well. Insert bolts through the holes. Place a washer and nut on the end of each bolt and screw them tightly. Now the brackets are holding the pipe to the board.
Slide the larger PVC pipe over the smaller one. The brackets should stop it from sliding all the way to the board. About 2 inches above the brackets, drill holes through both pipes. Drill another hole about 6 inches from the first.
Slide the larger pole away from the board until it covers about 1 foot of the smaller pipe. Drill two more holes through the smaller pipe using the existing two holes on the larger pipe. The hole nearest the end of the smaller pipe should be about 2 inches from the free end of it.
Insert a bolt through each of the holes near the end of the smaller pole. Secure them on the other end with wing nuts and tighten firmly. Now your roof rake is fully extended and ready to use.