Constructability and buildability
Can it be built the way it's modelled?
A clash-free model isn't a buildable one. Constructability reviews bring the people who will build the work into the model early, to check sequence, access, lifting, tolerances and temporary works.
Understand
What it is, in plain language
- Pedia · WorkflowsConstructability reviewChecking, with the people who will build it, that a design can be built safely, in a sensible order and at a sensible cost, before it reaches site.
- Pedia · WorkflowsFabrication models and DfMAModels detailed enough to make parts from, and design for manufacture and assembly (DfMA), where buildings are designed as kits of parts made off site.
- Pedia · GlossaryTolerance (clash)The distance below which a clash test ignores an overlap, so tiny modelling overlaps are not reported.
- Pedia · WorkflowsClash detection types (hard, clearance, duplicate)The three kinds of clash test — physical overlap, insufficient clearance and duplicated elements — and what each is good for.
Learn
Short lessons with a quick check
- Lesson · 5 min · quizWhat construction needs from the modelA design model answers design questions. Estimators, planners, site teams and fabricators ask different ones; knowing their questions is the first job of a BIM person on the contractor's side.
- Lesson · 5 min · quizRunning a constructability review with the modelClash detection finds things that overlap. A constructability review finds things that fit but can't be built well. Here's how to run one with the people who build.
Do
Tools that export Excel, PDF and Word
- Tool · Excel · PDF · Word3D IFC ViewerUse it to look at a model without installing software, or to show where requirements fail.
- Tool · Excel · PDF · WordBCF Viewer & ExporterUse it to read issues from BIM tools, or send your issues back to them.
- Tool · Excel · PDF · WordRFI RegisterUse it to track questions sent to the design team until they are answered.
How it works
The process, at a glance
The modeland its data
Common mistakes
What goes wrong most often on real projects.
- Treating a clash-free model as a buildable one.
- Reviewing only at the end of design, when changes are expensive.
- Inviting design managers but not the people who install the work.
- Keeping findings in minutes instead of the issue log.
Is it in place on your project?
Tick what is done — it counts towards the checkpoint on your learning path.
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