Cat House Size. Place wall boards against opening and draw cat house door with pencil. An adult domestic cats average height in the range of 8 to 10 inches or 20 to 25 cm.
A small-sized house wont even be comfortable for the cat. Cat doors should be 6 inches high. Add one to two inches.
This cat house can be easily converted to an insulated shelter if you add insulation sheets to the walls.
It should just be big enough and providing some extra space for the cat to turn around. Front door is flush with the 1x3 on its side. A small-sized house wont even be comfortable for the cat. You can get all the details on the Cattilac cat house here.