How to model a building product that gets demolished

Purpose

Model an existing building product that gets demolished during the project.

Prerequisites

The building product exists in the building model as an existing construction.

Steps

1. Find the building product in the building model tree.
2. Turn on the Demolition only checkbox in the Structure table (alongside Offset and Lifespan).
3. If the demolition has an offset start (it doesn’t happen at the project’s beginning), also enter the offset year.

What happens in the calculation

• A1-A3 is skipped entirely: no new production is counted.
• C3, C4 and D are calculated in the start year instead of in the last year of the study period.
• With an offset start, the C stages instead become B4C variants in the offset year. If the offset year falls in the assessment period’s last year, the normal stage is used instead.

Result

The building product contributes its demolition-related stages instead of a regular lifespan cycle. The contribution is shown under C3, C4 and D together with the rest of the end-of-life stage, not as modules of its own.

Don’t confuse the demolition checkbox with the “Renovation” project type. The project type doesn’t automatically set the demolition checkbox on anything, see Renovation: three things with the same name.

See also

• Demolition, offset start and renovation: which function should you use?
• How to model a building product installed later in the process