Air Tight Sealing

Key Takeaways: 

  • Airtight sealing is essential for energy efficiency, thermal comfort, and building durability under New Zealand’s H1 Energy Efficiency Code.
  • Reducing uncontrolled air leakage prevents heat loss, draughts, and moisture issues within walls and ceilings.
  • Combining flexible exterior sealants like Gorilla MS with high-performance expanding foams ensures complete airtightness. 
  • The SWS Airtightness System provides a three-layer seal for superior thermal, acoustic, and weather performance. 

Airtightness in Building Envelopes 

Achieving airtightness is one of the most effective ways to meet and exceed New Zealand Building Code Clause H1 Energy Efficiency requirements. Uncontrolled air leakage leads to heat loss, condensation, and poor indoor air quality, all of which reduce a building’s efficiency and comfort. By sealing gaps and joints properly, you can prevent unwanted air exchange, improve acoustics, and extend the building’s life span. 

Want to see how your insulation measures up? Use our R-Value Insulation Calculator to find out the effectiveness of your setup and identify areas for improvement. 

An airtight building envelope is best achieved using a system-based approach like the Soudal Window System (SWS). This model integrates three key functions: airtightness on the interior, insulation in the cavity, and weather protection on the exterior. 

For the exterior layer, Gorilla MS provides flexible, durable, and weather-resistant sealing that adapts to building movement and temperature changes. The middle insulation layer can be achieved using Pro Expanding Foam Click & Fix, Pro Expanding Foam Genius Gun, Pro Expanding Foam Aerosol, or Pro Expanding Foam Gun Grade, all of which deliver exceptional thermal and acoustic insulation. 

For precision application and permanent flexibility, FlexiFoam Click & Fix offers an adjustable, airtight expanding foam that adapts to irregular gaps and ensures consistent performance. 

Together, these products form a complete airtightness solution, supporting blower door test compliance, improving indoor comfort, and contributing to lower heating and cooling costs while reducing a building’s carbon footprint.

FAQs

Why is airtightness so important in modern buildings?

Because uncontrolled air leakage increases heating costs, reduces comfort, and can cause condensation or mould.

Which Soudal products improve airtightness?

The combination of Gorilla MS, FlexiFoam Click & Fix, and the Pro Expanding Foam range ensures airtight, weather-resistant, and insulated seals.

Can these foams be used around windows and doors?

Yes, they’re designed for perimeter sealing where airtightness, insulation, and flexibility are essential.

Do these products meet H1 Energy Efficiency requirements?

Yes, when used as part of a comprehensive sealing system, they support compliance by reducing air leakage and improving the thermal envelope.