Structural, MEP, and Civil Engineering Firms: Why Each Technical Lot Must Track Hours Differently

A technical engineering firm is not an architecture practice. The statement seems obvious, but its consequences for time tracking are rarely taken into account. Most engineering firms copy their tracking method from the lead architect, adopting the same phases, the same milestones, the same hour envelopes distributed uniformly. This is a mistake. Each technical lot -- structural, MEP, civil engineering -- has its own work rhythm, its own activity peaks, and its own causes of overruns. Ignoring these specificities means flying blind.

Why an Engineering Firm Can't Track Hours Like an Architecture Practice

The architect is the conductor of the project management mission. Their work follows a relatively linear arc: they produce a deliverable at each MOP phase, get it validated by the project owner, and move on to the next phase. The volume of hours is distributed fairly predictably from one project to another.

Engineering firms, however, face a different reality on three levels.

Radically different work rhythms depending on the lot. The structural engineering firm concentrates most of its hours on two or three intensive calculation phases. The MEP firm intervenes in fragmented bursts throughout the project, with peaks during coordination submissions. The civil engineering firm depends on external data -- topographical surveys, existing networks, permits -- that condition progress and create waiting periods followed by production sprints.

Inter-lot coordination adds an invisible layer of complexity. Each coordination meeting, each iteration to resolve a network conflict or a duct routing issue represents consumed time. This time doesn't appear explicitly in any mission phase, but it can represent 10 to 15% of an engineering firm's total hour volume.

Engineering firms work for multiple architects simultaneously. Unlike the architecture practice that manages its own projects, an engineering firm is often a co-contractor or subcontractor to five to ten different architects. Each has their own pace, their own deliverable requirements, their own deadlines. Tracking hours "the architect's way" would mean managing as many tracking systems as there are lead architects. It's neither sustainable nor relevant.

Key figure: Based on feedback from engineering firms with fewer than 20 employees, inter-lot coordination time (coordination meetings, email exchanges, plan revisions) represents between 12 and 18% of a mission's total hour volume. This item is almost always underestimated in initial costings.

Structural Lot: Long Phases and Intensive Calculations

The structural engineering lot may have the most contrasted hour consumption profile. Its work is massively concentrated on the detailed design phases, with periods of low activity upstream and downstream.

Structural Lot Specifics

The workload of a structural engineering firm is dominated by three major activities:

• The calculation phases (APD and PRO) represent the core of the work. Structural dimensioning -- reinforced concrete, steel frame, timber -- involves hours of modeling, Eurocode calculations, and regulatory verification. These phases are long, continuous, and require sustained concentration.
• Calculation notes and load distribution analyses constitute the main deliverables. Their production is linear: once started, it follows a predictable flow through to delivery.
• The construction phase (DET) is relatively light for the structural engineering firm, except in cases of modifications during construction or execution problems. Monitoring is generally limited to reviewing execution plans and answering site questions.

Typical Distribution Matrix -- Structural Lot

This distribution shows a marked peak in the APD and PRO phases, which together account for 55% of the total hour volume. It is on these two phases that overruns are most frequent -- and most costly.

Key takeaway: For a structural engineering firm, the overrun risk is concentrated in the APD-PRO phases. A weekly monitoring point on these two phases is essential. For other phases, bi-weekly monitoring may suffice.

Common Pitfalls of the Structural Lot

The first pitfall is program modification during calculations. A change in the structural grid requires redoing the modeling, sometimes from scratch. The second pitfall is waiting for geotechnical data: without a final soil report, the structural engineering firm works on assumptions that will need to be revised. Each revision generates additional hours that are rarely budgeted.

MEP Lot (HVAC, Plumbing, Electrical): Fragmented Interventions

The MEP engineering lot is the most difficult to track in terms of hours. Not because the total volume is larger, but because the work is broken into dozens of micro-interventions spread across the entire project duration.

MEP Lot Specifics

The MEP lot covers three disciplines -- heating, ventilation, air conditioning (HVAC), plumbing, and electrical -- that interact with all other project lots. This cross-cutting nature generates a unique hourly consumption profile:

• Short and frequent interventions. A question from the architect about a duct routing, a power adjustment requested by the project owner, a regulatory compliance check: each request takes between 15 minutes and 2 hours, but they accumulate.
• Permanent coordination with other lots. The MEP firm interfaces with the structural firm (structural openings), the civil engineering firm (connections), the architect (suspended ceilings, utility rooms), and sometimes the acoustics firm. Each interface generates exchanges, revisions, and adjustments.
• Frequent program changes. HVAC equipment choices, thermal comfort levels, environmental requirements: these parameters often evolve during the mission, each modification impacting sizing and plans.

Typical Distribution Matrix -- MEP Lot

Unlike the structural lot, the distribution is much more uniform. The DET phase represents 20% of the volume -- significantly more than for the structural lot, because MEP site monitoring involves on-site technical verifications (leak testing, balancing, commissioning).

Key figure: An MEP engineering firm handles on average 3 to 5 times more interactions per week with other lots than a structural engineering firm. Each untracked interaction represents a blind spot in time tracking.

The Challenge: Tracking 15-Minute Interventions

The real problem with the MEP lot is granularity. How do you track a 20-minute email response to the architect about a duct opening? How do you account for a 10-minute call with the HVAC contractor to clarify a specification? Taken individually, these micro-times seem negligible. Accumulated over an 18-month project, they can represent 100 to 200 untracked hours -- the equivalent of a month's work for an engineer.

A tracking tool suited to MEP engineering must therefore allow quick, frictionless entry of these short interventions. Half-day entry -- common in engineering firms -- is too coarse to capture this reality.

Civil Engineering Lot: Dependence on Field Data

The civil engineering lot has an atypical hourly consumption profile, dominated by a strong dependence on external data and local regulatory constraints.

Civil Engineering Lot Specifics

The civil engineering lot covers external works, stormwater management, connections to public networks, and roadways. Its characteristics:

• Strong dependence on field surveys. Without a topographical survey, without a plan of existing networks, without a utility company inquiry, the civil engineering firm cannot progress. Yet these data are often slow to obtain -- utility company responses (power, gas, water) regularly take 4 to 8 weeks.
• Local regulatory constraints. Local urban plans, drainage regulations, municipal road standards: each civil engineering project is specific to its territory. Studying these documents and ensuring compliance represents a non-compressible hour item.
• A schedule offset from other lots. The civil engineering firm often intervenes upstream (surveys, diagnostics) and downstream (road handover, final connections), with a reduced activity period during the detailed building design phases.

Typical Distribution Matrix -- Civil Engineering Lot

The civil engineering lot profile stands out with a significant weight in the ESQ-APS phase (23% combined), markedly higher than other lots. This reflects the diagnostic and data collection work required before any design can begin.

Key takeaway: The civil engineering firm experiences more waiting time than other lots. These waiting periods are not "free" time -- they generate file re-openings, context re-familiarization, and follow-ups that consume hours. Adapted tracking must distinguish productive time from follow-up and waiting time.

The Gap Between Theoretical Schedule and Reality

The recurring pitfall of the civil engineering lot is the gap between the planned schedule and field reality. A topographical survey delayed by three weeks shifts the entire design chain. A utility company that modifies its network routing requires a complete reworking of the civil engineering site plan. These uncertainties are lot-specific and don't impact other engineering firms in the same way. Yet in a consolidated tracking system, they are invisible -- lost in a total hour count that says nothing about their cause.

Inter-Lot Interfaces: The Invisible Time You Mustn't Forget

Beyond the work specific to each lot, there is a category of time often ignored in both costings and tracking: inter-lot coordination time.

What Coordination Covers

• Coordination meetings. On a medium-sized project (20 to 50 housing units), expect a coordination meeting every two to three weeks during the PRO-EXE phase. Each meeting mobilizes a representative from each lot for 2 to 3 hours, plus 1 to 2 hours of preparation and follow-up. Over an 18-month project, that represents 40 to 80 hours per lot.
• Conflict resolution. An HVAC network crossing a load-bearing beam, a stormwater pipe interfering with an electrical network: each conflict detected in coordination generates hours of rework for at least two lots. These hours don't belong to any particular phase -- they are the direct consequence of project complexity.
• OPC interface management. On projects with a dedicated OPC (project scheduling) manager, engineering firms are called upon for schedule updates, progress reports, and specific coordination points. This administrative time adds to the technical time.

Who Accounts for What?

This is the thorny question of any multi-lot mission. When two engineering firms each spend 3 hours resolving a coordination conflict, each charges these hours to their own project. But to which phase? Some assign them to the current phase (PRO or EXE), others create a "coordination" category -- when the tracking tool allows it.

The absence of a clear convention for allocating these hours distorts the distribution matrices and makes comparisons between projects difficult. Best practice is to create, within the project structure, a dedicated "coordination" item distinct from production phases. This item should be budgeted from the initial costing.

Key takeaway: A "coordination" item budgeted at 12 to 15% of the total hour volume is a realistic minimum for an engineering firm working on a multi-lot project. Failing to plan for it guarantees an overrun on the production phases.

Organizing Tracking by Lot: Adapted Milestones and Reporting

Now that the specifics of each lot have been identified, how do you concretely structure time tracking in a multi-lot engineering firm?

A Project Structure by Lot

The first rule is to clearly separate lots in the tracking tool. A multi-lot project (structural + MEP + civil engineering) should not be tracked as a monolithic block. Each lot must have its own hour envelope, its own milestones, and its own overrun alerts.

Concretely, for a 30-unit collective housing project, the structure could look like this:

Residence Bellevue Project -- Multi-Discipline Engineering

The "coordination" item represents 12% of the total here -- in the lower range of what is typically observed. On a complex project (renovation, constrained site, many stakeholders), this ratio can reach 18 to 20%.

Milestones Adapted to Each Lot

Engineering firm milestones don't always coincide with the lead architect's milestones. Some examples:

• Structural lot: the key milestone is the validation of the final calculation note (end of PRO phase). At this point, 55% of the budget should be consumed. If the BCR (budget consumption rate) exceeds 60% at this stage, the project is on alert.
• MEP lot: the critical milestones are the submission of coordination plans (APD) and the completion of technical specifications (PRO). The uniform profile of the MEP lot requires more regular monitoring -- ideally weekly -- rather than widely spaced checkpoints.
• Civil engineering lot: the determining milestone is obtaining utility company responses (APS phase). Any delay on this milestone mechanically shifts the rest of the mission. Tracking must incorporate waiting times as a standalone indicator.

Inter-Lot Reporting for Coordination Meetings

The reporting intended for the project manager cannot be a simple hour total. It must show, lot by lot:

• The consumption rate by phase (where do we stand relative to budget?)
• Current alerts (which lots are over budget or at risk?)
• Identified causes (program modification, data delays, excessive coordination?)
• End-of-mission projections (EAC by lot)

This reporting allows the lead architect to have a consolidated view of the project's technical and financial progress. It also serves as a factual basis for negotiating amendments when overruns are attributable to program modifications or unforeseen contingencies.

For technical engineering firms managing multiple projects in parallel, this reporting by lot and by project is the only way to detect drift before it becomes irreversible.

Each technical lot has its own DNA when it comes to hour consumption. The structural engineering firm concentrates its effort on two critical phases. The MEP firm disperses its effort across dozens of micro-interventions. The civil engineering firm contends with field uncertainties and utility companies. Applying a uniform tracking grid to these three realities means condemning yourself to discovering overruns once the project is delivered.

The solution lies in an adapted tracking structure: distribution matrices specific to each lot, an explicitly budgeted coordination item, milestones aligned with the true tipping points of each discipline, and reporting that speaks the language of each profession. Only under this condition does time tracking cease to be an administrative chore and become a genuine management tool.