What is an addon?

Addons, or markups, are indirect costs that apply to the whole estimate. Addon amounts can be based on a wide variety of costs such as the total cost of the estimate, category costs (labor, material, and equipment, for example), or selected hours.

Examples of markups
Possible markups include Such as
Lump sum amounts Permit fees
Fixed amounts Telephone hookup
Fixed amounts with break points Insurance
Straight percentage amounts Profit, sales tax
Percentage amounts with break points Bonds