29/10/2026
Over time, structures change. However, drawings and BIM models usually stay the same. As a result, a gap appears between existing and as-built conditions.
This gap is especially relevant in renovation, retrofit, and refurbishment projects, because.
- Buildings get altered over decades: walls moved, services rerouted, extensions added, often without the drawings being updated. Was it documented? Probably not.
- Structures shift over time. Settlement, thermal movement, and ageing materials can mean that floors, walls, and ceilings no longer match the geometry shown in the original design documentation.
- Manual surveys often capture less spatial detail than thorough reality-capture workflows, especially in complex or hard-to-reach areas.
- There was never any production of as-built documentation. A lot of buildings only have records of their original designs, not what was actually constructed.
When a design team works from any of these flawed sources, the resulting model or drawing set inherits every one of those inaccuracies and passes them straight into procurement, fabrication, and site coordination.
