What Is Building Physics and Why It Matters

Building physics is the study of how heat, air and moisture move through a building. Understanding these mechanisms is essential for diagnosing envelope problems correctly.

The Three Forces

Heat Transfer

Heat moves through the building envelope via conduction, convection and radiation. Where insulation is missing, thin or compromised, heat escapes — creating cold surfaces that can lead to condensation.

Air Movement

Air carries moisture. When warm internal air leaks through gaps in the envelope, it cools and deposits moisture within the construction — causing interstitial condensation.

Moisture Transport

Moisture moves through buildings in three ways: liquid flow (leaks), capillary action (rising damp) and vapour diffusion (condensation). Each requires a different investigation approach.

Why Building Physics Matters for Diagnostics

A leak stain on a ceiling could be caused by:

• A roof membrane breach (liquid water)
• Interstitial condensation (vapour)
• Air leakage depositing moisture (air movement)

Without understanding the mechanism, repairs are guesswork. Building physics analysis ensures the correct diagnosis is reached before any repair work begins.

The Vertex Approach

Vertex applies building physics principles to every investigation — combining visual inspection, moisture measurement, thermal imaging and thermal analysis to reach evidence-based conclusions.