To determine minimum roof drain square feet, what must be added to the roof area of a roof measuring 40' by 20' with a vertical wall on one side measuring 4' by 40'?

To determine the minimum roof drain square footage, you first calculate the total area of the roof, which is the main part of the structure you are considering for drainage. The dimensions of the roof provided are 40 feet by 20 feet, which results in a roof area of 800 square feet (40 x 20 = 800).

Next, the vertical wall, which measures 4 feet high and 40 feet long, contributes additional area that must be factored in because it drains water as well. The area of this wall can be calculated as 4 feet multiplied by 40 feet, giving you an additional 160 square feet.

To find the total area that needs drainage consideration, you combine both the roof area and the wall area:

800 square feet (roof area) + 160 square feet (wall area) = 960 square feet.

For roof drainage calculations, a common rule is that one drain is needed for every 1,000 square feet of area. Depending on the specific code or local requirements, this area might be reduced to allow for better drainage efficiency.

In this scenario, if you specifically add the 800 square feet of roof area and 160 square feet from the wall, you are ultimately looking for