The Main House dimensions are 24' x 36' (7.33 x 11 meters), an 864 sq.ft. (80.5 square meters) "footprint". The second floor is somewhat smaller, because the "walls" are actually the sloping roof trusses. Measuring those portions with a reasonable ceiling height, the second floor has about 250 sq.ft. (23.25 square meters) more of usable space, with additional generous cabinets and closets built into the areas with sloped ceilings.
This 2-Bedroom, bath-and-a-half version of The Affordable Natural House (shown below) has a open ceiling over the main Living/Dining areas (known in our area as a "cathedral" ceiling). In the 3-Bedroom version, there is a second bedroom in place of this raised ceiling.