In one form or another, this question is one of the most frequent requests we receive from our readers. Unfortunately, it is also one of the few questions that we simply cannot answer very specifically. Can you tell me how much it costs to take a vacation or send my kids to college? How much should I expect to spend on a new kitchen? What is the "average cost" of a dinner for two or a night out with friends?”

All of the above questions contain so many variables that it is impossible for anyone to answer them accurately without first asking several additional questions and gathering much more information. The same is true when calculating the cost to build a new house. Let's begin by considering what square foot construction costs really are, nothing more than the total cost of a given project divided by the total number of square feet in that project.

So, a 2,000 square foot house with total construction costs of $250,000 would cost $125 per square foot to build. Spend another $20,000 on a gourmet kitchen, an elegant master bath, marble tiles in the lounge, a fancy curved staircase or any other combination of "above average" features or finishes and that same 2,000 square foot house would now cost $135 per square foot to build; an increase of 8%. Now consider the structure itself, if the house in question is a single story, with all of the finished area on one floor, the roof would have to be large enough to cover the entire 2,000 feet of living space. Turn that single level into a two story and the roof size is instantly reduced by 50% because the second floor system became the roof for half of the area on the first floor.

Increase the roof pitch from 3/12 to 12/12 and the roof area (including framing and sheathing) quickly increases by 35%. Of course, these examples are oversimplified because they don't consider any other differences like the need to add the cost of staircase and take away the space they occupy, or in the case of a slab-on-grade foundation, the difference between the costs of a concrete slab versus a wooden floor system, but hopefully the point has been made.

The costs of similarly sized houses can also vary considerably due to the shape of the building, the number of corners or offsets in the design, the type of foundation and required local footing depth, the pitch of the roof, and many other design characteristics that are not directly related to the size of the house.