Expert: Dan Griffin - 7/31/2008

Question
How do you figure the sq footage of 20ft wide x 29 long with an 8ft ceiling and 7/12 pitch roof with 16 in over hang a-frame type

Answer
Lenton there are lots of differcent kinds of square feet.  Lenton, there is only one way to compute square feet, length in feet times width in feet.  Your question is asking for many different computations.  Lenton, this is really sounding like a homework question.  I think you are trying to come with the square foot of roofing.  It is not an A frame at 7in12, you wouldn't be able to stand up in it.  If it really is an A frame, the numbers are not working out as there cannot be an 8' ceiling inside a less than 6 foot roof peak.

Floor SF = 20x29
Ceiling SF = same
Wall SF= 20x8x2 plus 29x8x2 (assumes no interior walls)

Each side of the roof SF will require calculating the hypotenuse of a right triangle formed by the mid point rise and half the total building span = SQRT of 5.8333'(70") rise ^2 (squared) plus 10' ^2 (you will need to add any additional bottom eave overhang) times 29' (if the gable ends overhang you will need to increase the 29' number appropriately)  Remember there are two sides to the roof.