I am often asked how to calculate the square footage of a house. This is in honor of my brother who hates top ten lists.
Here are my top ten things you should know when measuring a house.
1. Living area is calculated from outside measurements. Garages are measured and deducted out of the living area.
2. On the second level, living area is only measured to a 5' wall, and the average height of the room must be 7 feet. Anything below five feet is not considered living area, but can potentially add value.
3. Many times, Realtors include finished basements (below grade) area in the total square footage. Normally, finished basements are valued slightly lower than finished above grade areas. Therefore, an appraiser separates the two areas in order to be more precise. Basement is classified as any area below grade.
4. Often on one building sketch I have three classifications for basement. Finished basement, semi-finished basement, and unfinished basement. Finished basement is area that is equal to the construction quality of above grade living area, heated and cooled with flooring. Semi-finished area can be an area that is heated and cooled, but lacks finish flooring, or it could be totally finished, but not heated and cooled. Unfinished basement is area that is not heated and cooled, no finished flooring, and is typically painted cinderblock walls.
5. Sunrooms can be included in the square footage if they are finished to the same quality grade as the rest of the house, and are heated and cooled.
6. Stairways are included. Two story foyers are deducted out of the second level. If you can't walk on it, it is not considered living area.
7. Brick veneer is included in the square footage of a house. New construction plans typically figure square footage without including the depth of the brick veneer. When an appraiser measures square footage, the brick is included in the total square footage.
8. When subtracting out the attached garage the depth of the wall shared with living area is included in the total square footage of the house, and not the size of the garage.
9. Living area over a detached garage. I separate the finished area over a detached garage from the living area in the main house.
10. Use a nylon 100' tape measured in tenths. Although I sometimes use a laser tape for measuring on the second level, they can sometimes pick up side walls when reading through cased openings, and are not as reliable.
Those are the basics to measuring a house. Good Luck.