Contingency (Construction)
Money set aside for the surprises that every project eventually has.
Quick Answer
Contingency in construction is a budgeted reserve set aside to cover unforeseen costs and uncertainty in scope, design, pricing, or site conditions. It is not a pad for extra work. It is drawn down as risks materialize, and the amount is generally set according to how complete and well-defined the design is.
The Full Picture
No estimate is perfect. Drawings are incomplete, prices move, hidden conditions appear, and details change as the design matures. A contingency acknowledges this honestly by carrying a reserve in the budget, rather than pretending that the base estimate will be exactly right. The amount is a judgment about risk, and it should shrink as uncertainty is resolved.
Several contingencies can exist on one project, and they are controlled by different parties. A design contingency in early estimates covers the gap between current and final design. A construction or contractor contingency covers risks within the contractor's control and means, such as buying losses or trade coordination. An owner's contingency covers owner-side changes and unforeseen conditions. Contracts spell out who controls each and how it may be used.
How much to carry is both a science and an art. Cost estimating guidance, including AACE International's recommended practices, describes approaches ranging from simple percentages based on estimate class to risk-based analysis. As a general pattern, earlier estimates with less design completion carry larger contingencies, and the percentage declines as drawings are finalized.
In preconstruction, contingency is a frequent topic in GMP negotiation, where the owner and contractor settle how much risk is carried, who can spend it, and what happens to the unspent balance. Clear rules prevent disagreement later, and transparent tracking of each drawdown helps maintain trust between the parties.
Real Examples
Common Misconceptions
People assume: People assume contingency is padding or profit.
Actually: it is a reserve for risk that is tracked and, depending on the contract, any unspent amount may return to the owner.
People assume: People assume a fixed percentage always applies.
Actually: the right amount depends on design completeness, project complexity, market conditions, and the specific risks identified.
Frequently Asked Questions
What is contingency in construction?
Contingency is a budgeted reserve for costs that cannot be foreseen precisely, such as incomplete design, price changes, or unexpected conditions.
What is the difference between contingency and allowance?
An allowance covers a specific known item that has not been selected. A contingency covers unknown or unforeseen costs and is not attached to a particular scope item.
How much contingency should a project carry?
It depends on design completeness and risk. Early estimates generally carry more, and the percentage decreases as the design is finalized. Methods range from fixed percentages to risk-based analysis.
Who controls the contingency?
The contract determines it. Owner contingency is controlled by the owner, while a contractor contingency within a GMP is usually used by the contractor with reporting to the owner.
What happens to unspent contingency?
That depends on the contract. In many GMP arrangements, unspent contingency is returned to the owner or shared according to agreed terms.