How Revit Clash Coordination Reduces Costly Rework in Construction Projects

 

Projects require seamless integration of multiple disciplines, including architectural, structural, and MEP (Mechanical, Electrical, and Plumbing) systems.  However, this complexity often leads to design conflicts, commonly known as clashes.  If not detected early, these clashes result in expensive rework, delays, and material & labour waste, significantly inflating project costs.

 Studies have highlighted the significant financial burden of clashes in construction projects.  Like, rework and material waste due to clashes can account for up to 30% of project costs.  On average, each unresolved clash may cost approximately $1,500+.  These clashes can result in significant financial losses when taken as a whole, highlighting the significance of proactive clash detection and resolution in project management.

Common Causes of Clashes in Construction

1. Interdisciplinary Conflicts

Conflicts arise when the architectural, structural, and MEP systems clash after progressing to LOD 300-350, when models are enriched with system-specific details like hanger placements, insulation, clearances, and equipment access.

 Even with individual discipline-specific modeling done correctly, combined trade coordination often reveals overlooked spatial and functional conflicts, especially when designs are translated into construction-level details.

 The structural team places transfer beams below a mechanical room to support large equipment loads.  However, the MEP team has already routed primary HVAC ducts and large diameter piping directly through this zone, assuming a clear soffit based on the previous design.

 Such conflicts typically surface after trades begin detailed coordination—this is too late for design changes to happen seamlessly, and often results in expensive structural revisions, resequencing trades, and fabrication delays

2. Spatial Overlaps (Component Buffer Clashes)

These clashes are not about obvious overlaps—but rather about clearance, maintenance access, and constructability issues that arise in congested zones when shifting from design intent to real installation.

 At LOD 350/400, systems include real-world details like hanger supports, insulation thickness, prefabricated spools, valve access panels, fireproofing layers, and ceiling substructure.  This level of detail reveals erroneous spatial assumptions made in earlier stages of design. A prefabricated duct riser is modeled to pass through a shaft, but the actual size, insulation thickness, and seismic bracing requirements leave no clearance for the adjacent fire riser and electrical tray.

 This is a frequent clash type in hospital projects, data centers, and high-density mechanical rooms, where space is extremely tight, and equipment access for maintenance is mandatory.  Rework is required and project delays result as a result of the disruption to pre-fabrication workflows.

3.Workflow Sequencing Issues (Construction Timing Conflicts)

Even if clash detection is done well, poor trade coordination at the site level causes on-site clashes because systems are installed out of sequence or using different layouts than what the model shows.

 When MEP subcontractors work with shop drawings that are slightly disconnected from the federated model, installation teams sometimes ‘adjust on the fly’, leading to as-built conditions that clash with other trades’ work.

 The fire sprinkler contractor installs piping runs before structural embeds for ceiling hangers are placed, requiring later rework where piping obstructs embed locations.

4.Lack of Communication between Teams

 Because correcting work often involves physical demolition, re-pouring of concrete, or voiding inspector pre-approvals, these sequencing conflicts typically do not become apparent until LOD 400 installation coordination meetings—all of which drive up costs. With multiple revisions happening during construction, not all changes make it back into the coordinated BIM model, especially for minor field adjustments.  Over time, these undocumented changes snowball into larger constructability clashes.

 Last-minute RFIs, product substitutions, and site-driven changes frequently bypass the formal update cycle even with a common data environment (CDE). The MEP contractor uses a pre-insulated ductwork system because of the long lead times. However, the new insulation thickness makes it harder to clear the ceiling, which was not told to the electrical team, whose conduits were planned for the same ceiling space. This is a classic clash type in large, phased projects (hospitals, airports, high-rises), where overlapping trades and constant updates create an environment where what’s on paper no longer matches reality on-site.  This breakdown triggers rapid-fire RFIs, out-of-sequence rework, and schedule compression, leading to quality risks.