An airtightness test result that exceeds the target is not a crisis — it is information. Every building that fails an airtightness test has leakage pathways that can, in principle, be found and sealed. The question is where to look first, how to prioritise the investigation, and what sealing approach will most efficiently close the gap between the measured leakage rate and the required target.
In Saudi Arabia’s construction environment, a first-pass airtightness test result that exceeds the Saudi Building Code target or the project specification target is extremely common. Studies of commercial construction in comparable climates consistently show that buildings tested without a targeted airtightness programme during construction typically achieve two to four times higher leakage than their design targets. The gap is not a reflection of poor workmanship in isolation — it reflects the inherent difficulty of achieving consistent airtightness across the thousands of joints, penetrations, and interfaces that make up a modern commercial building envelope, without specific tools and processes designed for this purpose.
This article provides a practical guide to diagnosing and prioritising airtightness failures in Saudi commercial buildings, from the most common and highest-impact leakage sources to the most effective diagnostic tools and remediation approaches.
Step 1: Understand the Scale of the Failure
Before investigating specific leakage locations, establish the scale of the gap between your measured result and the target. A building testing at 4.5 ACH50 against a target of 3.0 ACH50 needs to close a 33% gap — achievable with targeted manual sealing of the highest-impact locations. A building testing at 12.0 ACH50 against the same target has a fundamentally different challenge — one that requires a comprehensive approach, very likely including AeroBarrier aerosol sealing for the distributed leakage that manual methods cannot efficiently address.
The remediation strategy should be proportionate to the scale of the failure. Chasing individual small gaps with sealant when the building is leaking at four times the target rate is an inefficient use of resource. Understanding the gap first allows the remediation approach to be designed appropriately.
Step 2: Look at the Highest-Probability Leakage Locations First
Research in comparable building types and climates consistently identifies the same categories of locations as the highest contributors to total envelope leakage. In Saudi commercial buildings, investigate these first:
Service Penetrations Through the Envelope
Every pipe, conduit, cable tray, duct, and structural support that passes through an external wall, roof, or ground floor slab is a potential leakage source. In a large commercial building, there may be hundreds of such penetrations. Individually, each may be a small leakage point. Collectively, they can contribute 20% to 40% of total envelope leakage.
During the pressurised airtightness test, hold a smoke pencil or theatrical smoke source near each identified penetration while the building is under pressure. Air movement at the penetration will carry the smoke — either drawing it in (if the smoke is at an infiltration point under depressurisation) or pushing it away (under pressurisation). Mark each active leakage point for sealing.
Top and Bottom Wall Plates
The junction between wall framing and the floor or ceiling structure above and below is one of the most consistently significant hidden leakage sources. In framed construction, this junction is inherently imperfect — the gap between the top plate and the ceiling element above it may be only a few millimetres, but it runs the full perimeter of every external and internal wall that forms part of the air barrier. The cumulative area of this gap can be substantial, and it is largely inaccessible for inspection once drywall and finishes are in place.
AeroBarrier aerosol sealing is particularly effective at this type of distributed, inaccessible leakage because the sealant travels with the pressurised air to every leakage pathway, including those behind finished surfaces that a technician cannot physically access.
Window and Door Perimeters
The junction between window and door frames and the surrounding wall construction is a classic high-leakage zone. Factory-applied seals on the frame itself are typically adequate, but the interface between the frame and the rough opening — sealed during installation with foam, mastic, or tape — is highly variable in quality. Thermal cycling in Saudi Arabia’s climate causes significant expansion and contraction that stresses these seals, and they frequently develop gaps within the first year or two of operation.
Check window and door perimeters systematically, particularly at corners and at the interface between the frame and any structural reveals. Ensure that internal and external seals are both present and continuous — a single-sided seal that is open on the other face provides much less resistance to air movement than a correctly detailed double-sealed installation.
Recessed Light Fittings and Ceiling Penetrations
In buildings with recessed ceiling lighting — standard in Saudi commercial fit-outs — each fitting is a direct connection between the occupied space and the ceiling plenum. The ceiling plenum in many Saudi commercial buildings is effectively connected to the outdoor environment through HVAC penetrations, structural joints, and roof assembly gaps. Every unguarded recessed fitting is therefore a pathway for air exchange between outside and inside.
Retrofit sealing of recessed fittings from above, using airtight covers or intumescent sealing materials, is a straightforward manual operation that can contribute significantly to overall leakage reduction when fittings are the dominant leakage source.
HVAC Penetrations and Dampers
Supply and return ductwork passing through the building envelope or through the air barrier at the boundary between conditioned and unconditioned spaces must be sealed at every penetration and equipped with motorised dampers that close when the air handling system is not operating. Missing or poorly sealed duct penetrations, and dampers that do not close fully or are held open by controls faults, are significant leakage sources that are often overlooked in airtightness remediation programmes.
Step 3: Use Thermal Imaging to Locate Hidden Leakage
During the pressurised airtightness test, thermal imaging of the building’s internal surfaces can reveal hidden leakage pathways as temperature anomalies — areas where cold infiltrating air cools the wall surface below the surrounding temperature, creating a visible thermal gradient. In Saudi Arabia’s summer conditions, the temperature difference between outside and inside is so large that even moderate air infiltration produces clearly detectable thermal signatures.
Thermal imaging is particularly valuable for locating leakage through wall assemblies, above ceiling panels, and at structural connections that cannot be directly observed or tested with smoke. The combination of pressurisation and thermal imaging provides a comprehensive map of leakage locations that guides the remediation programme efficiently.
Step 4: Consider AeroBarrier for Distributed Leakage
When the airtightness test failure reflects distributed leakage across many small pathways — as opposed to a small number of large, identifiable gaps — manual sealing becomes inefficient. Locating and sealing hundreds of small gaps individually is slow, expensive, and incomplete: some will inevitably be missed, and the inaccessible ones cannot be addressed at all.
AeroBarrier aerosol sealing addresses distributed leakage comprehensively by pressurising the building and introducing sealant aerosol that travels to every leakage pathway automatically. It seals the accessible and inaccessible gaps simultaneously, with real-time monitoring of the total leakage rate confirming progress toward the target. For buildings that have failed airtightness tests by more than 30% to 40% above target, AeroBarrier typically provides a faster, more complete, and more cost-effective remediation than manual sealing alone.
Step 5: Retest to Confirm
After remediation works are complete, retest the building. The retest confirms that the target has been achieved, provides the post-remediation performance certificate required for regulatory submissions and certification bodies, and — if combined with the pre-remediation result — documents the improvement achieved.
Conclusion
A failed airtightness test is the starting point of a remediation process, not the end of the road. The sequence is clear: understand the scale of the failure, investigate the highest-probability leakage locations, use thermal imaging to find hidden pathways, select the right sealing approach for the leakage pattern, and retest to confirm. Aeroseal Arabia provides the complete remediation sequence — ATTMA-certified testing, thermal imaging, targeted manual sealing, AeroBarrier aerosol sealing for distributed leakage, and retest certification — as an integrated service for Saudi commercial and institutional buildings. Contact our team to discuss remediation for your building’s airtightness test failure.
