BIM Coordination

What is BIM coordination?

BIM coordination is the structured process of comparing and resolving conflicts between separate discipline models before construction begins. Instead of each team (architect, structural engineer, building services) working in isolation and discovering clashes during construction, coordination brings those models together in a shared digital environment, identifies issues early, and ensures all parties agree on the solution before a single brick is laid.

The process centres on a federated model, which combines discipline-specific models without merging the source files. Each team keeps its own model in its chosen authoring tool, exports key stages to IFC format, and uploads the file to a Common Data Environment where all parties can view it, compare it with other disciplines, and detect conflicts.

How does the federated model work in coordination?

Rather than forcing all disciplines into a single software platform, the federated approach lets each team use the tools they prefer. The architect works in Revit or ArchiCAD, the structural engineer uses StaadPro or a similar package, and the MEP/TZB installer designs ducts and pipes in their own environment. At key project milestones, each discipline exports its model to IFC format and deposits it in the shared CDE.

The CDE then assembles these separate exports into a unified view. Clash detection software reads all the IFC files, compares them geometrically, and produces a report flagging every overlap, undersized clearance, and conflict. Because the source models remain separate, updating the architect's design means replacing only the architectural IFC file; the structural model stays as it was, and the comparison happens again at the next cycle.

What is a coordination cycle and how does it reduce site problems?

A coordination cycle is a round of model comparison, issue identification, resolution, and verification. A typical cycle follows these steps:

The benefit is cumulative. The first coordination run on a project that has never been checked typically reveals dozens or hundreds of issues, depending on complexity. As each cycle resolves them, the count drops. By the time construction documents are finalized, the model should be free of clashes. This means the site teams face no surprises and can proceed with confidence, rather than having to improvise solutions in real time.

The alternative, traditional coordination via 2D drawings and email, leaves conflicts hidden until walls are framed or concrete is poured. At that point, fixing them costs time, money, and often compromises the design intent or thermal performance of the building envelope.

Who participates in BIM coordination on a residential project?

Coordination typically involves:

• Architect – responsible for spatial layout, openings, structural supports, and overall geometry. Owns the architectural model.
• Structural engineer – designs beams, columns, slabs, and foundations. Owns the structural model.
• Building services engineer (TZB) – designs ventilation, heating, cooling, plumbing, and electrical systems. Owns the MEP/TZB model.
• Coordination lead or BIM manager – convenes meetings, runs clash detection, tracks issue resolution, and maintains the CDE.
• Passive-house certifier (if applicable) – may review the model to verify thermal continuity and airtightness strategies.

On a small, simple project, one person might fulfill several of these roles. On a larger project, each is typically a separate firm or department.

How are coordination issues identified and resolved?

Once clash detection runs, the report lists every conflict with a severity rating and the geometry involved. A typical workflow for resolving an issue looks like this:

Not every clash has an obvious resolution. Some require trade-offs: a duct may move to a less ideal route to avoid the beam, or a pipe may be routed in series rather than parallel to reduce ceiling depth. These decisions are made collaboratively during coordination meetings, where each team understands the constraints of the others and the decision is documented in the issue register.

Why does coordination matter for passive-house design?

Passive-house construction is unforgiving. The air barrier must be continuous and cannot be punctured by unexpected ducts or pipes. Thermal bridges must be designed out, not improvised around. If a duct or pipe is found to penetrate an insulated wall or roof after framing begins, the fix almost always introduces a thermal bridge or air-leakage path that undermines the energy performance the design promised.

Coordination ensures these clashes are resolved before construction, preserving the integrity of the thermal and air-barrier strategy. A passive-house project without coordination almost always runs into surprises mid-construction. With coordination, surprises are rare.

What is the minimum scale for coordination to be worthwhile?

Coordination overhead is real. Setting up a CDE, defining Level of Development standards, running clash detection software, and holding coordination meetings all consume time and money.

For a simple single-storey house with minimal building services, a simple structural grid, and no basement, the overhead may exceed the benefit. Coordination shines when:

• The building is over 200 square meters or has more than one storey.
• Heat recovery ventilation or complex ductwork is part of the design.
• Radiant heating or cooling loops need to be routed through walls and ceilings.
• Underfloor thermal insulation and services compete for the same depth.
• The structural grid is complex or includes cantilevers.
• Multiple contractors will be involved (reducing informal, on-site coordination).

On a typical Slovak residential project of this scale, the cost of coordination is 2-4 percent of design fees. The cost of a single on-site duct reroute, structural repair, or thermal-bridge fix is often 5-10 times higher. The return on investment is clear if the project meets any of the criteria above.

How does a BIM Execution Plan govern coordination?

A BIM Execution Plan is a document that defines the coordination rules for the entire project. It specifies which disciplines must participate, what IFC export frequency is required, which CDE platform will be used, who runs clash detection and how often, what tolerance levels trigger a clash report, and what the escalation path is if a clash cannot be resolved by the affected parties. The BEP ensures coordination is consistent, not ad hoc, and prevents misalignment between teams about roles and timelines.