Infrared Roof Surveys: How They Are Performed and Why They Matter

Infrared (IR) roof surveys are the gold standard for detecting moisture in commercial roofing systems without destructive testing. Here's how they work and when to use one.

How Infrared Detection Works

During the day, the sun heats the roof surface and the insulation beneath it. After sunset, dry insulation releases heat quickly (cools fast) while wet insulation retains heat longer (cools slowly). An infrared camera captures this thermal differential — wet insulation appears as warm (bright) areas while dry insulation appears cool (dark). The survey must be performed at night, typically 1–2 hours after sunset, on a day with significant solar gain.

What the Survey Provides

A complete IR survey maps moisture distribution across the entire roof, identifying: total wet area percentage, location and extent of moisture pockets, drainage patterns, and areas of progressive moisture migration. This data directly determines whether a roof qualifies for coating restoration or requires replacement.

IR Survey vs. Core Sampling

IR survey identifies where to core sample — it doesn't replace core sampling. The survey guides efficient placement of core samples, which then confirm moisture presence and assess insulation condition. Best practice: IR survey first, then targeted core samples at identified anomalies.

When to Commission an IR Survey

Before any restoration or replacement decision on a roof older than 10 years. When multiple leaks are occurring across the roof. When building purchase or sale involves commercial property with aging roofs. The survey cost ($0.01–$0.03/sq ft) pays back many times over in accurate decision-making.