Survey Protocol and Equipment
Our IR surveys are conducted by certified thermographers using calibrated long-wave infrared cameras with thermal sensitivity of 0.05 degrees Celsius or better. The camera is calibrated before each survey for ambient conditions including air temperature, wind speed, and surface temperature. Surveys are conducted at a consistent walking pace with the camera held at a consistent height above the membrane surface, producing a systematic coverage pattern across the entire roof.
Each anomaly detected during the walk is flagged with a GPS waypoint and photographed with both the IR camera and a visible-light camera. The IR image shows the thermal pattern; the visible image shows the corresponding membrane location. Both images are referenced to the roof zone diagram in the final report. We do not conduct IR surveys in conditions that will produce unreliable results, including wind above 15 mph, recent rainfall on the membrane surface, or cloud cover that prevented adequate solar loading during the preceding day.
What IR Scanning Identifies and What It Does Not
IR scanning reliably identifies moisture-laden insulation that has stored more heat than the surrounding dry areas. It is highly effective on single-ply membrane systems over polyiso or EPS insulation, the most common configuration on post-1990 commercial buildings throughout the St Louis metro. Anomalies are confirmed with core samples before the report categorizes them as wet insulation. The combination of the thermal screen and the physical core confirmation is what produces a defensible recover-versus-replace recommendation.
IR scanning is not reliable on ballasted systems where the ballast layer masks the thermal differential, on roofs with thick concrete topping slabs, or on systems with multiple layers of membrane and insulation that produce complex thermal stratification. For those systems, nuclear gauge scanning is the preferred moisture detection method. We identify the right tool for each building's system type before mobilizing, and we are direct when IR scanning is not the right choice for a particular application.
Combined IR and Core-Sample Reports
An IR survey alone is a screening tool. It identifies locations for follow-up investigation, not a definitive saturation map. Our standard protocol combines the IR survey with targeted core samples at a representative sample of the anomaly locations: one core per anomaly cluster identified by the IR, plus one core in the driest area of the roof to establish the baseline. The combined report gives the building owner both the aerial view from the IR scan and the physical confirmation from the cores.
For St Louis buildings going through a pre-sale assessment or a capital planning review, the combined IR and core report is the most complete moisture documentation we can produce. It satisfies the documentation requirements of most lenders and institutional buyers active in the Clayton, Chesterfield, and Earth City commercial corridors, and it provides the data depth that an independent assessor needs to evaluate the roof capital requirement without relying solely on our interpretation.
Common False Positives in the St Louis Market
HVAC exhaust heat rising through the membrane, roof penetrations with equipment operating at above-ambient temperature, areas with black-body caulk or patches that absorb and retain heat differently than the surrounding membrane, and standing water on the surface all produce thermal anomalies that can be mistaken for wet insulation. We identify and document all apparent false positives in the anomaly log before reporting and verify with physical cores before categorizing any anomaly as wet insulation.
In the St Louis industrial corridors, rooftop HVAC equipment density on manufacturing and distribution buildings can be high enough that the equipment-related thermal signatures create a complex background against which moisture anomalies need to be carefully distinguished. Our thermographers are experienced with this condition and manage the survey routing to create the clearest possible comparison between equipment-influenced zones and field areas where wet insulation is the primary suspect.
Seasonal Scheduling for St Louis IR Surveys
The thermal window for effective IR scanning in the St Louis market runs from late April through mid-October. The earlier months of May and June offer the advantage of consistent temperature swing after sunset combined with the fact that spring storms may have recently opened flashing failures that are still admitting moisture, making saturation patterns easier to detect. Late summer scanning in August and September captures the accumulation from the full summer heat cycle.
Winter scanning is technically possible but significantly less reliable in St Louis because the low sun angle and reduced solar intensity during December through February do not load the roof assembly enough to create a reliable temperature differential after dark. We do not recommend winter IR surveys for recover-versus-replace decisions in the St Louis climate. For buildings that need a moisture assessment in winter, nuclear gauge scanning is the more reliable method during cold months.
