BEYOND THE FACADE | PART 4: Seeing beyond visual inspection - with thermal imaging
Using thermal imaging to reveal hidden performance issues
Thermal imaging has a significant role to play when considering facade performance. A facade can be specified to the highest standard, engineered with precision, and constructed by an experienced team - and still underperform.
The gap between design intent and built reality is one of the most persistent challenges in facade engineering. Insulation can be incorrectly installed or compressed. Junctions can be poorly detailed or inadequately sealed. Fixings can create unintended pathways through the thermal envelope. In many cases, none of this is visible once the building is complete.
Thermal imaging changes that. By detecting surface temperature differences that are invisible to the naked eye, a thermal imaging camera allows our engineers to see exactly where a building envelope is losing heat, where air is finding its way through, and where performance is falling short of what was intended - whether the building is brand new or has been in use for decades.
What is a thermal bridge?
A thermal bridge is a localised area of a building envelope where heat flows more readily than through the surrounding construction. It is, in effect, a weak point in the thermal barrier - a path of least resistance through which energy escapes in winter and enters in summer.
Thermal bridges occur most commonly at junctions and penetrations: where a structural slab meets an external wall, where a facade bracket passes through insulation to connect to the building frame, at window and door perimeters, and at corners or changes in geometry. They can also result from workmanship issues – for example, insulation that has been compressed, displaced, or incorrectly cut around a fixing.
The consequences go beyond energy loss. A thermal bridge creates a cold spot on the interior surface of the facade. In humid conditions, that cold surface can fall below the dew point of the internal air, causing condensation to form - which in turn can lead to mould growth, damage to finishes, and poor indoor air quality. For occupants, the result is discomfort and, potentially, health concerns. For building owners, it is a maintenance liability and a reputational risk.
What is an airtightness failure?
Airtightness failures are distinct from thermal bridges, although the two are often found together. A thermal bridge is a conductance issue - heat passing through a solid material. An airtightness failure is a leakage issue - gaps, cracks, or unsealed junctions through which air moves physically in and out of the building.
Uncontrolled air infiltration carries heat with it, undermining the performance of even the best-insulated envelope. In winter, cold air drawn in through gaps chills the interior and drives up heating demand. In summer, warm humid air entering a cooled building can cause interstitial condensation within the construction. Beyond energy performance, air leakage can introduce noise, dust, and pollutants, and can compromise the effectiveness of mechanical ventilation systems.
For buildings targeting Passivhaus certification - where airtightness is one of the five fundamental pillars of the standard - even small failures can jeopardise compliance. But airtightness matters well beyond Passivhaus: it is a basic requirement of a well-performing building envelope at any specification level.
How thermal imaging works
A thermal imaging camera detects infrared radiation emitted by surfaces and translates it into a visual image where different temperatures appear as different colours. Warmer areas show as reds and yellows; cooler areas as blues and purples. What this means in practice is that any part of a facade or internal surface that is behaving differently from its surroundings - whether hotter or cooler than expected - becomes immediately apparent.
Thermal imaging surveys are most productive during the winter months, when heat escaping from a warm interior through weaknesses in the envelope shows up clearly on the external facade. Viewed from outside, thermal bridges and air leakage points appear as warm patches glowing against the cooler surrounding surface - brackets, slab edges, poorly sealed junctions, and gaps around frames all becoming visible in a way that no visual inspection could ever reveal.
Internal surveys show cold patches on wall and ceiling surfaces where heat is escaping or cold air is infiltrating. External surveys show warm patches on the facade where heat is leaking out from within. Together, the two perspectives give a comprehensive picture of where the envelope is performing as intended and where it is not.
What it finds in practice
In our experience, thermal imaging surveys consistently reveal issues that would otherwise go undetected until they manifest as visible defects or occupant complaints.
Common findings include:
Facade brackets and fixings penetrating the insulation layer, creating linear or point thermal bridges at regular intervals across the elevation.
Insulation that has been compressed, displaced, or omitted entirely during construction, leaving areas of the envelope significantly under-performing.
Unsealed service penetrations - pipes, cables, and ducts passing through the air barrier without adequate sealing - acting as direct conduits for air leakage.
Frame-to-structure junctions at window and door openings where the thermal break has been bridged or the seal has failed.
Slab edges and floor-to-facade junctions where structural continuity creates a direct thermal path through the envelope.
Perimeter seals around glazing units that have deteriorated, been incorrectly applied, or were never continuous in the first place.
These findings are as relevant on a newly completed building as on one that has been in service for twenty years. On a new build, they represent construction defects that can and should be rectified before handover. On an existing building, they are the starting point for a targeted remediation programme - one that addresses real, located problems rather than working from assumptions.
Why it matters
The implications of thermal bridging and airtightness failures extend across several areas that matter directly to building owners, developers, and occupants:
Energy performance: Heat loss through unaddressed thermal bridges and air leakage paths can significantly increase a building's operational energy demand, undermining targets set at the design stage and increasing running costs for occupants.
Condensation and mould: Cold interior surfaces caused by thermal bridges create the conditions for condensation and mould, with potential consequences for occupant health, material durability, and the building owner's liability.
Occupant comfort: Draughts, cold spots, and uneven surface temperatures are among the most common occupant complaints in poorly performing buildings. Identifying and addressing their root causes is essential for delivering a building that feels as good as it performs on paper.
Handover and warranty evidence: A thermal imaging survey carried out at practical completion provides an objective, documented record of the envelope's condition at handover. This is increasingly valuable as a warranty tool, and as evidence in the event of any future dispute about performance.
Passivhaus and low-energy certification: For projects targeting Passivhaus or other low-energy standards, thermal imaging provides a means of verifying that the as-built envelope meets the stringent performance requirements of the standard - and of identifying any areas that need attention before certification.
Making performance visible
At Henriksen Studio, we believe that evidence matters. A building's performance should not be a matter of assumption or hope - it should be something that can be measured, documented, and demonstrated. Thermal imaging is one of the most powerful tools we have for doing exactly that: turning the abstract language of U-values and air permeability targets into a clear, visual record of how a facade is actually performing.
Our thermal imaging capability sits alongside our existing suite of services - including coating measurement, glazing analysis, and remote monitoring - as part of a commitment to facade engineering that does not stop at practical completion.
Whether you are commissioning a new building, managing an existing asset, or investigating a performance concern, we can provide the evidence you need to understand what your facade is doing and what, if anything, needs to change.
To find out more about our thermal imaging and facade performance services, get in touch with the team at Henriksen Studio.
