Life-cycle assessment for existing buildings and refurbishment
A life-cycle assessment calculates environmental impacts over the life cycle of a building. The indicators for each building material come from databases. What does not come from a database are the quantities: how much concrete, how much masonry, how much insulation is actually built in. That is exactly where the assessment of an existing building fails.
When the need arises
- Weighing refurbishment against a replacement new build, when embodied energy counts
- Funding or certification that requires an assessment
- Comparison of several refurbishment options
- Reporting obligations for which building data must be substantiated
Where the data comes from
This service calculates with geometry: areas, heights, openings, orientation, build-ups of building elements. In a new building, the design model provides this information. In an existing building it does not exist, and that is precisely the usual obstacle.
We collect this basic data during the as-built survey anyway. The same capture that produces floor plans and the room book also provides the values used in this calculation. No second site visit and no second data collection are needed.
- As-built data capture – the capture on which this is based
- Scan-to-BIM – the as-built model, when quantities are to be calculated rather than estimated
- DIN 277 – the areas that feed into almost all of these calculations
Why the quantities are the difficult part
In new construction the quantities come out of the model. In an existing building there is no such model, and the building file records the state at the time of construction, not the state after forty years of alterations. Common practice is therefore to estimate using indicators per square metre. That is enough for an overview; it is not enough for a decision between refurbishment and demolition, because the answer depends on exactly these quantities.
From an as-built model, on the other hand, quantities of building elements can be derived. What the model cannot tell you is the build-up behind the surface; that requires openings or an investigation of the building elements. At this point we state what has been measured and what has been assumed, rather than mixing the two.
More in this group
These services build on the same capture. Anyone who needs one of them usually needs a second one as well.