Evidence Domain

Building Physics

What it studies

The physical behaviour of buildings: heat, air, moisture, sound and light as they move through structures and spaces. It is the engineering science beneath every environmental quality claim — what a building actually does thermally, acoustically and atmospherically, as opposed to what its design intended.

Why it matters

Every environmental requirement the strategy specifies — acoustic class, thermal range, ventilation rate — is delivered or defeated by building physics. It also explains the performance gap: the systematic difference between designed and measured building behaviour, which is why commissioning measurement, not design calculation, is the evidence standard.

Questions it answers
  • Will this building deliver the specified environmental conditions in operation?
  • Where do thermal, acoustic and air-movement problems physically originate?
  • What does the design-versus-operation performance gap look like here?
  • Which environmental requirements can this envelope and services architecture actually support?
Evidence sources
  • Building physics research and engineering standards
  • Commissioning and measurement data
  • Performance-gap literature
  • Building simulation (validated against measurement, not substituting for it)
Design and policy implications

Environmental criteria specified with verification methods; commissioning measurement contractual, not optional; building appraisal including physics capability before concept commitment; retrofit strategies grounded in measured rather than assumed performance.

Related methods
Common misuse

Simulation substituting for measurement: designed performance reported as delivered performance. The performance gap is well documented; claims about a building's environmental quality that rest on models rather than commissioning data should be treated as intentions.

Further research

Performance-gap causes and closure methods remain active research; in-use monitoring at scale is making the gap more visible and less excusable.