This doghouse is suitable for a small to medium-sized dog with a 9 square foot base. I purchased my materials at Home Depot. Note that the doghouse uses an existing floor--in my case, an outdoor deck--so no base is included in this plan. If you need a base, purchase additional materials as required.
Tools needed: hammer or cordless drill, table saw, circular saw, jigsaw, tin snips, small paintbrush
1 sm. box approx. 1-1/2 roofing nails
1 sm. box approx. 2 1/2" galvanized common nails or screws
1 sm. box approx. 2" galvanized finishing nails
1 pack of asphalt/fiberglass shingles
2 10' sections of 2" drip cap
1 quart exterior paint
2 sheets 7/16" OSB (oriented strand board)
1 sheet blue insulating foamboard
Step 1: Mark and cutout parts
Make a sandwich with the two OSB sheets on the outside and the foamboard inside. Make sure that the edges line up, then fasten the sheets together with 4 nails or screws to prevent shifting. Draw the parts on the top sheet as in the first drawing below. Then nail/screw additional fasteners about every foot just inside the edge of each part to be cut. This will hold the parts together when they are cut. Cut the parts out using the circular saw. Use the sabre saw to cut the corners of the door opening. Cut two equilateral triangles 10" on a side from the door opening scrap. Attach the two right-triangle sections to make the back wall. (I nailed 1x2's to the top and bottom inside edges to hold them together.) For the ridge, carefully cut the 2x4 4' long and 2 5/8" wide. Then use the table saw set at 30 deg. to rip this piece into a diamond shape (see 2nd drawing).