# Total Horizontal Area Estimate

Total Horizontal Area Estimate. There are several methods to estimate a building or a project. One of them is by estimating it based on its floor. This estimate cannot give you an exactly 100 % correct estimate, but it can give you a good range or estimate.

#### Floor Area Estimate

James E. Rowings, Jr. explained that this method is most appropriate for hospitals, stores, shopping centers, and residences. Floor area must be the dominant attribute of cost (or at least it is assumed to be by the estimator). There are several variations of this method. One of them is Total Horizontal Area Estimate.

#### Total Horizontal Area Estimate

For this variation, it is assumed that cost is directly proportional to the development of horizontal surfaces. It is assumed that the cost of developing a square foot of ground-floor space will be the same as a square foot of third-floor space or a square foot of roof space. From historical data, a cost per square foot is determined and applied uniformly to the horizontal area that must be developed to arrive at the total cost.

#### Total Horizontal Area Estimate Example

Assume that a historical file contains a warehouse building that cost \$2.4 million that was 50 ft x 80 ft with a basement, three floors, and an attic. Determine the cost for a 60 ft x 30 ft warehouse building with no basement, two floors, and an attic.

Solution for Total Horizontal Area Estimate Example :

1- Determine the historical cost per square foot :

Basement area : 4000
1st Floor : 4000
2nd Floor : 4000
3rd Floor : 4000
Attic : 4000
Roof : 4000

TOTAL : 24,000

\$2,400,000/24,000=\$100/ft^2

2- Calculate the total cost for the new project :

1st Floor : 1800
2nd Floor : 1800
Attic : 1800
Roof : 1800

TOTAL : 7,200

7200ft^2 x \$100/ft^2 = \$720,000

We hope that the explanation above helps you in estimating based on horizontal area better. Next post we will post about other method of estimating by using another floor are estimate. Beside this Total Horizontal Area Estimate, you can also read other articles about estimating as below :