You should always have shelter for your dog, even he is only outside for an hour at a time. If your dog spends most of his time outside, this is the perfect solution. A wooden dog house, like anything else wooden, needs additional protection such as siding. The additional protection not only protects the wood, but keeps the elements and wind from seeping between the wood.
Decide how big you need the dog house. Use the 2-inch x 4-inch boards to build a frame for the dog house. The frame will have four separate sides. Cut enough boards for four top pieces, four bottom pieces and eight side pieces. Cut an additional 12 pieces for supports. Cut the supports 4 inches shorter than the boards for the sides.
Measure in 2 inches on each of the boards, cut for the side of the frames. Nail the shorter pieces to the longer pieces on the 4-inch side of the 2-inch x 4-inch board. You will now have a 4-inch by 4-inch post with 2 inches at each end left over on the longer board.
Stand one of the side piece up and nail the top piece in the L created by nailing the shorter side board to the longer board. Fit another side piece at the other end of to piece. You should now have an upside-down U. Flip this piece over and nail a bottom board into the L shapes created on the side boards. You should now have a perfect rectangle or square (depending on the size of the dog house). Repeat Step 3 for the remaining three sides.
Fit two of the sides together. Use the metal L brackets to hold the sides together by fitting them into the inside corners of the sides. Nail the L brackets 1 inch down from the top of the frames. Using 3-inch nails or screws, add at least six to each corner, giving extra support to hold the frame pieces together. You should now have a complete 3-dimensional square or rectangle frame. If the walls are long, use the extra four short pieces from Step 2 for center supports on the walls. Just slide them in vertically, then nail through the top and bottom pieces to hold them in place. Use 3 nails in a triangle pattern to hold them in.
Measure from outside edge to outside edge of what will be the side of the dog house and write the measurement down. Measure the same side from top to bottom (outside edge to outside edge of the frame) and write this measurement down. Measure the exact opposite side and make sure the measurements are the same.
Use those measurements to cut a piece of plywood for the side of the dog house. Use the first piece of cut plywood as a stencil to draw the cutting lines for the second wall. If the measurements were a bit different, you will have to hand-measure the plywood and cut a piece to fit the other side, instead of tracing the first piece. Screw the plywood onto the frame. You should no longer be able to see any of the 2-inch x 4-inch boards used to make that side of the frame.
Measure the back wall of the dog house. Measure from the outside edge of the plywood to the outside edge of the plywood on the opposite wall and from top to bottom of the back frame. Cut the piece out of the plywood and screw it to the back wall.
Repeat Step 7 to make the front wall, but before screwing the cut plywood to the frame, cut an upside-down U out of the front. The size of the U will depend on the size of the dog. It will need to be at least 4 inches taller than your dog's withers. Screw the piece of plywood to the front wall of the dog house.
Turn the dog house over. Measure the bottom the same way you measured the sides. Cut the plywood for the bottom. Cover the top of the plywood with linoleum. Use linoleum glue to hold the linoleum in place. Screw the bottom board onto the dog house, making sure the linoleum is "inside" the dog house. You should not be able to see the linoleum side while screwing the floor into place.
Flip the dog house over. Using 2-inch x 4-inch boards, make the trusses for the roof. Cut the boards at the proper angle for the pitch and size roof you want. Nail the trusses together into a triangle. You should not need more than three trusses, unless the dog house is overly large. Nail the trusses to the top of the frame. Cut a piece of plywood for each side of roof (each slope). Screw the plywood to the roof. Cut two triangle shaped pieces to fill in the front and back of the roof. Screw those pieces in the triangle-shaped opening on the front and back of the roof.
Cut the roofing felt to fit the roof. Use small tack nails on the edges to hold the roofing felt in place. Starting at the bottom, add a layer of shingles. Nail the shingles into place, making sure to overlap the bottom row. Complete the other side of the roof the same way. After both sides are shingled, lay a shingle over the point of the roof (you may need more than one, depending on the length of the shingles and the length of the roof). Make sure the shingle is evenly draped over the top so it lays on both sides. Nail it in place. This will keep water from seeping in through the top crack between the plywood on the roof.
Add your choice of siding or paint to the walls of the dog house. While the dog house can be set directly on the lawn, it will last longer if you build a pad under it using pavers.