Let's first divide the diagram of the house into two rectangles and a trapezoid, since we can calculate the area of each of these figures.

Now, the area of the larger rectangle=$40 feet \times 20 feet$

$=800 feet^{2}$

The area of the smaller rectangle=$25 feet \times 6 feet$

=$150 feet^{2}$

The area of the trapezoid A=$\dfrac{1}{2}h\left(b1+b2\right)$

The height (h) is 6 feet, and the two bases (b1 and b2) are 8 and 11 feet.

A=$\dfrac{1}{2}6\left(8+11\right)$

A=$\dfrac{1}{2}6\left(19\right)$

=$57feet^{2}$

Therefore Adding all three areas gives a total area of the house =800+150+57

$= 1,007 feet^{2}$