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Estimating: Identifying Risks Before They Become Costs
- Expert view
By André Béliveau, Director of Estimating and Cost Control
After 40 years in cost estimation, one thing is clear to me: the largest cost variances don’t always stem from what’s obvious.
They’re often hidden in the details.
Poor coordination between two disciplines. Underestimated site conditions. A specific requirement buried in a bid. An overly optimistic assumption. A reference project that, in the end, isn’t as comparable as we thought.
Taken separately, these elements may seem minor. But when they aren’t detected early enough, they become gray areas. And it is precisely these gray areas that can turn, during construction, into cost overruns, delays, or conflicts.
In the field, this is probably the most important lesson my experience has taught me: a good estimate isn’t just about determining a cost. It’s about understanding the project well enough to anticipate what could cause it to go off track.
A number is not always just a number
One perception I still encounter frequently is that an estimate is viewed as a fixed amount.
A figure is produced, and it is expected, in a sense, to become a certainty.
But an estimate is not a cost commitment. It represents the most accurate assessment possible of a project at a specific point in time, based on available information, certain assumptions, and the stage of design.
This is a fundamental distinction.
During the functional and technical program phase, for example, the available information remains very preliminary. Work is sometimes based primarily on floor areas, a program, and a few general parameters. The estimate then relies more heavily on ratios, comparable projects, and assumptions.
“As the project progresses, this information becomes more precise. Plans are developed, systems are defined, quantities become more reliable, and uncertainties decrease.”
The Real Challenge: Data
This is also why contingency budgets must evolve in line with the project’s level of definition.
I still see organizations hesitating to allocate a sufficient contingency budget at the start of the design phase, as if doing so reflected a lack of confidence in the estimate. In fact, the opposite is true.
An adequate contingency budget simply acknowledges what we know—but also what we do not yet know.
Rigor consists precisely in making this uncertainty visible rather than artificially removing it from the budget.
What seems minor can end up costing a lot
Among the situations I encounter most frequently, coordination between disciplines remains a major challenge.
An element may be indicated in the architectural drawings with a reference to the structural design. The architectural estimator may then assume that it will be included in the structural estimate, while the structural estimator assumes the opposite.
The result: no one has accounted for it.
Conversely, the same element may also be included twice.
This seemingly minor inconsistency quickly becomes an issue when it appears in the bid documents. A contractual ambiguity can then lead to a request for additional work, a source of dispute between the client and the contractor, or, ultimately, an additional cost.
And this type of gray area isn’t limited to the coordination of plans.
Site accessibility, temporary facilities, management staffing requirements, material losses, construction methods, specific warranties required in the specifications, or cost indexation can all have a significant impact on the budget.
Existing buildings illustrate this reality particularly well.
A structure may be more damaged than anticipated. The actual scope of decontamination may exceed initial estimates. Certain conditions only become apparent during stripping or demolition.
In this context, conducting more in-depth investigations early on can sometimes entail additional costs. However, it is often better to invest in gaining a better understanding of existing conditions before the bid process begins than to discover them later in the form of a change order.
The sooner we assess the situation, the sooner we can act
When I first started in cost estimation, the estimator’s role was much more limited. We would receive the documents, prepare the price, and our work remained essentially focused on the budget.
Today, organizations have a better understanding of the value of incorporating cost estimation much earlier in the process. And this shift is significant, because cost estimation can then play a much more strategic role.
“When we get involved at the start of a project, our role is no longer simply to confirm how much a solution might cost. We can challenge assumptions, compare scenarios, identify risks, detect inconsistencies, and propose alternative approaches while there’s still time to act.”
A preliminary budget can thus enable a client to assess the feasibility of their project, secure funding, or adjust certain directions before the design is too far along.
As the plans progress, successive estimates then make it possible to track the project’s progress and verify that the decisions made remain consistent with the financial objectives.
This ongoing involvement acts as a form of oversight. When an ambiguity arises, it can be flagged. When an assumption seems tenuous, it can be challenged. When a potential cost overrun becomes apparent in the documents, clarification can be requested before the request for proposals is issued.
The sooner these issues are resolved, the more options remain available.
What only experience can reveal
The role of estimator has changed dramatically. Quantity takeoff tools, digital models, and new technologies now make it possible to work much more quickly—provided the available information is of high quality. A BIM model, for example, can be extremely useful if the data is well-structured. Otherwise, certain quantities remain difficult to extract, and part of the work must still be done manually.
And even with the best tools, there remains one aspect that no technology can fully replace: judgment.
Assessing the logistics required for a complex construction site. Selecting a truly comparable reference project. Determining a realistic material loss rate. Understanding how a contractor might organize their work. Recognizing when an assumption seems overly optimistic.
This insight develops over time.
It is built through completed projects, analyzed bids, observed discrepancies, and problems encountered in the field.
In a context where production timelines are getting increasingly compressed and the industry must grapple with a significant succession challenge, this experience becomes particularly valuable.
Because moving faster should never mean losing sight of what lies ahead.
An independent perspective for better decision-making
What I particularly appreciate about my work at DECASULT is being able to perform this role with complete independence. We are not affiliated with any contractor, and our primary responsibility is to provide the client with the most accurate assessment possible and to point out any risks or inconsistencies we observe.
This independence is even more valuable because it is supported by a multidisciplinary team. Civil engineering, structural engineering, architecture, mechanical engineering, and electrical engineering: each discipline has its own specificities and requires a detailed understanding of construction methods, quantities, and costs.
Drawing on this range of expertise allows us to deepen the analysis and, above all, to consider the project as an integrated whole rather than simply the sum of its parts.
It is this holistic perspective that we strive to bring to every stage of a project, from the initial budget to the approval of changes during construction.
“Because, ultimately, the value of a good estimate lies not only in the accuracy of the figure itself, but also by everything it helped anticipate before the project even reached the construction site.”
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