If you work with light façade systems, you already know this: every major project ends up at the test bench. Air permeability, water tightness and wind resistance have become standard requirements for developers, architects and system manufacturers.
And in the middle of that entire assembly of profiles, anchors and glazing, a discreet component carries much of the outcome: the window seal that closes the curtain wall, both in fixed panels and operable areas.
Let’s look at what is actually tested and how sealing rubbers are prepared to pass those tests with confidence.
What Is Really Tested in a Curtain Wall System?
In an accredited laboratory, the façade mock-up is assembled just like on site and subjected to a sequence of standardised tests:
- Air permeability: pressure differentials are applied and the amount of air leaking through joints and interfaces is measured.
- Water tightness: simulated rain is combined with increasing pressure to determine when leakage begins.
- Wind resistance: positive and negative loads simulate strong gusts to assess deformation and overall façade safety.
The required classifications vary depending on country, wind zone and building type, but the market trend is clear: higher classes and greater safety against extreme events.
The Role of Rubber Seals in Aluminium Window Systems
In a light façade system, rubber seals are far more than a simple “finishing detail”:
- They ensure the perimeter seal between glass and profile.
- They compensate tolerances and movements due to wind loads or thermal expansion.
- They channel water into drainage chambers, preventing visible leakage.
When discussing rubber seals for aluminium window systems, both the section design and the choice of material (EPDM, TPE, co-extrusions, etc.) are critical for maintaining elastic properties over the years, even under UV radiation and continuous rain/sun cycles. Many of these solutions fall under the category of extruded rubber seal or sealing rubbers, which must remain stable under demanding environmental conditions.
If you want to learn more about types and installation, ISOGOM offers a complete guide on seals for aluminium window systems.
How Seals Are Prepared to Pass Performance Tests
Before reaching the test bench, the work involving seals and profiles begins much earlier:
- Seal geometry design: the profile is defined considering drainage chambers, compression zones and potential critical points (corners, horizontal/vertical joints, slab interfaces). Good design avoids water pockets and leakage paths.
- Selection of suitable material: a façade exposed to coastal weather is not the same as an interior project. Materials are chosen for weather resistance, elastic memory and dimensional stability.
- Prototype and installation adjustments: the seal is tested on a mock-up to review closing pressure, ease of installation and to ensure no pinching or stress points occur. Small design adjustments at this stage can make a major difference during testing.
- Seal continuity control: even the best seal fails if joints are poorly executed. Workshops and installers must avoid poorly finished cuts, open joints or areas without compression.
What the Market Is Asking for Today
Developers, architectural studios and system manufacturers consistently demand:
- Higher air/water/wind performance, exceeding minimum regulatory classes.
- Longer-lasting seals, reducing maintenance and post-sales claims.
- Tailor-made solutions, not only catalogue items but seals specific to new profile systems.
- Technical support during design and façade testing phases.
For this reason, working with manufacturers capable of developing a tailor-made seal for your curtain wall system—accompanying you from the first sketch to the final test—is increasingly valued.
In fact, global façade market reports point in exactly this direction: more sustainable envelope solutions, improved thermal performance and greater integration of intelligent technologies in curtain walls and façade systems.
If you are designing a light façade or preparing your system for air/water/wind tests, ISOGOM can support you with customised seals and profiles, along with flexible production through our rubber and thermoplastic extrusion lines.
Preparing your next façade test?
Let’s talk about the seal you need to pass it on the first attempt. Contact us.
