Adjust your takeoff quantities to the purchase minimums and account for waste. For example, 97 linear feet of conduit would be rounded to 100’ as you cannot purchase partials. In addition, for certain items like wire and conduit, you’ll need to add a waste percentage.
Create a bill of material that you can send to your supplier to get a firm quote for the project. At a minimum, create a bill of material for lighting fixtures and switch gear that you can send out for a firm quote as this fluctuates from project to project.
Add labor units in man hours for each task/activity using past production history and/or national cost data for standard installations and extend out by multiplying the labor unit by the quantity to come up with your labor total in man hours for the task.
Adjust labor factors for difficulty by percentage of the task. So, for example, installing a lighting fixture at 20 feet versus 10 feet requires a 30% increased labor adjustment according to NECA.
Determine your crew average “Burdened Labor Cost” for the project, taking into consideration any prevailing wage requirements, after-hours work, overtime, etc. Multiply this number by the total labor hours to arrive at your labor cost.
Add lost time percentage for non-productive time. On every project, there will be some degree of lost time or non-productive time where your workers are waiting on other trades, going to pick up missing supplies, etc. You’ll want to include some continency on your labor budget to account for this based on the risk of the project.
Extend out material quantities and multiply by cost. You should have a firm material quote by now to get your material totals per task. Once you have this, add the totals from each to arrive at your material project totals.
Add your “Project Overhead” expenses, i.e., permit, onsite storage, dumpsters, temporary electric, lifts, etc. Note: This overhead is different than the indirect overhead expenses required to run your business.
Add your labor, material and project overhead totals up, and move to an estimate summary sheet to arrive at your direct costs to complete the project.