- 01Renovation risk is mostly about the unknown existing condition; an accurate as-built BIM converts unknowns into measured facts before design starts.
- 02Existing drawings are almost always wrong — walls move, services get rerouted, and decades of undocumented changes accumulate.
- 03As-built BIM catches conflicts (a new duct route hitting an unrecorded beam) in design, where they cost nothing, instead of on site.
- 04Scope as-built BIM to the renovation’s scope: capture the whole building at low LOD, and the intervention zones at the detail you’ll design in.
The defining risk of any renovation is that you don’t fully know what you’re working with. The existing drawings are old, incomplete, or simply wrong; services have been rerouted; structure has been altered. Every one of those unknowns is a potential change order waiting to detonate mid-construction. An accurate as-built BIM is how you defuse them — by turning the existing building into measured, coordinated data before you commit to a design.
Why existing drawings can’t be trusted
Buildings drift from their drawings the moment they’re occupied. Tenant fit-outs move partitions, MEP is rerouted for new equipment, structural openings are cut, and almost none of it is documented back to the record set. Designing a renovation on legacy 2D drawings means designing against a fiction — and the gap between fiction and reality shows up as rework.
Scoping as-built BIM for renovation
- Capture the whole building at a modest LOD for context and coordination.
- Model intervention zones (where you’re actually working) at the LOD you’ll design and coordinate in — often LOD 300+ for congested plant rooms and risers.
- Prioritise the systems your renovation touches: if it’s an MEP retrofit, the existing MEP and structure matter most.
- Verify critical dimensions and clearances that the new design depends on.
Design on facts, not fiction
Successful renovations start from an accurate picture of what exists. Spetia Engineering delivers as-built BIM scoped to your renovation, so your designers coordinate against measured reality and your project avoids the mid-construction surprises that wreck renovation budgets.
