Saw the 4-by-4-inch beams into four pieces to a length of 6 feet.
Measure and mark out the four corners of the shelter on the ground with a tape measure. The dimensions should match the dimensions of the generator. A 4-by-4-foot shelter is typically large enough to house most home generators.
Dig out the four corner holes in the ground with a post-hole digger to a depth of 2 feet. Use a tape measure and a level to make sure the holes are the exact depth and are level.
Mix the cement and water in a large bucket according to the instructions on the cement mix. Place the posts into the poles and pour the cement in. Use a level to make sure the posts are all even. Allow 24 hours for the posts to dry completely.
Measure out the plywood sheets to a height of 4 feet and a width of 4 feet with the tape measure. The plywood sheets should be 1/4 inch in thickness. Cut the plywood sheets to size. The back of the structure and two sides are needed at this time.
Attach the plywood sides and back to the posts using a power screwdriver and wood screws.
Use a utility knife to cut a piece of heavy-duty outdoor tarp to fit on the inside floor of the structure. Lay the tarp on the ground inside the structure.
Line cinder blocks on the ground inside the structure and then place a piece of plywood over them to create a raised floor. The plywood floor should be cut to approximately 3 1/2 feet long and 3 1/2 feed wide.
Use a screwdriver to attach simple hinges to the left-hand side of the piece of plywood to be used for the front door. Space the hinges out both on the plywood and the front left 4-by-4 post using a tape measure and pencil to mark the mounting holes.
Attach an eye bolt and latch to the right-hand side of the front door and the right 4-by-4 post.
Lay the top piece of plywood, which will serve as the roof, across the top of the four support beams. Use a hammer and nails to secure the plywood to the beams.