How Much Contingency Does a Build Need?
Why a construction budget needs a contingency line, how to size it for your project, and the surprises it most commonly absorbs on custom and rural builds.
By Tireless Construction ·
Last updated
A contingency is not pessimism. It is the acknowledgment that a custom home is priced before anyone has dug a hole, and that some of what is priced is an educated estimate. Budgets without a contingency do not avoid surprises; they simply have no way to pay for them.
What contingency actually covers
- Site conditions discovered during excavation, such as rock, poor soil or a high water table
- Allowance overruns when real selections cost more than the placeholder figure
- Material price movement between bid and purchase on long-lead items
- Code or inspection requirements that were not anticipated at design
- Genuine changes you decide to make once you can stand inside the rooms
Sizing it
The right size depends on how much of the budget is estimated versus contracted, and on how much is unknown about the site. A build on a serviced suburban lot with a complete finish schedule and firm subcontractor pricing carries less risk than a rural build with an unevaluated site and open allowances. Discuss the number explicitly with your builder rather than letting it stay implicit.
Keep it separate and visible
A contingency that lives inside other line items gets spent invisibly. Track it as its own line, approve draws against it deliberately, and review the remaining balance at each major milestone. What you do not spend, you keep.