How to Estimate Building Plans

Calculate the length, width, perimeter and floor area of the project. Calculate foundation depths from dimensions shown on the building plans. Calculate wall heights and areas. Calculate roof slope and area. Familiarize yourself with the building plans. Request missing information from the plan's architect or engineer required to fully describe each material.

Set up the estimating spreadsheet. Provide vertical columns for the name of each product or material shown on the plans; the amount of material (area, volume or number of items); its unit cost (cost per area, volume or number ); total cost; and cost of labor to install it.

List each item or material required by the job. Organize the items into the 16 divisions recommended by the Construction Specifications Institute index as follows:

1. General requirements

2. Site construction

3. Concrete

4. Masonry

5. Metals

6. Wood and plastics

7. Thermal and moisture protection

8. Doors and windows

9. Finishes

10. Specialties

11. Equipment

12. Furnishings

13. Special construction

14. Conveying systems

15. Mechanical

16. Electrical

Use the CSI detailed format to check completeness of your own work.

List the amount of material required by the building plans on the estimating spreadsheet in the column adjacent to each listed material.

Determine the cost of materials. Take a copy of the spreadsheet to the construction desk of your material supplier for him to list the unit price and total price for the total for each item.

Determine labor costs. Choose one of three ways to estimate labor costs: your own experience; a construction estimating standard such as R S Means Building Construction Cost Data; a bid from a subcontractor that specializes in installing the listed materials.

Add the total material cost to the total labor cost to estimate the cost to construct the building plans.