ISOVER – helping to meet the Passivhaus standard

The team at Lester Weir Joinery & Construction Ltd has recently completed the company’s latest high performance thermal, airtightness and moisture control project, at the site of a new home build in Portadown in County Armagh.

The build involved the construction of a 2,000sqft Passivhaus standard home, making the most of the site orientation, whilst also utilising high quality construction materials and practices, to ensure excellent thermal, airtightness and moisture control results.

The use of the ISOVER Vario system, including Vario Bond, the newest addition to the system, has meant that work around ensuring high airtightness and moisture control results has been as swift as possible.

Vario Bond was used to seal window, door and ceiling to wall junctions. This allowed for quick and easy installation, as it removed the need for a mesh overlay when plastering these details. Other products from the Vario system being used in the build are Vario KM Duplex Airtight Membrane and Vario Multitape SL adhesive tape.

In addition to the use of the Vario system, ISOVER Metac High Performance Mineral Wool was used in the pitched roof to ensure thermal performance and comfort within the building.

ISOVER Marketing Manager, Valerie Dent, commented, “The Vario System offers the complete solution for builds where high airtightness performance is essential.

“Vario can help save time for the installer; ensure moisture control, air flow management and thermal comfort for future users of each building it is installed in. Combined with Metac High Performance Mineral Wool, ISOVER offers the safest and most complete system available on the market.”

The overarching strategy for the build was to ensure that all penetrations within the shell of the building were minimised and addressed. Where there was a penetration of the airtight membrane, for example, it was sealed using ISOVER’s Vario KB1, Multitape or Double Fit Mastic. The contractor also ensured his team had undergone specific training so that they were able to spot issues that could have the potential to threaten the airtightness and thermal performance of the building.

The contractor’s biggest challenge was overcoming hurdles concerning this being the team’s first Passivhaus standard build. The need to attain the passive standard was addressed by the contactor by contacting ISOVER’s technical team for information, as well as attending the Vario Airtightness Training Course in the ISOVER Technical Academy in Kingscourt, County Cavan. Topics such as product suitability, product application and details on how to work to a high spec were all covered at the course.

For more information on ISOVER products and systems visit the website at You can also sign ip for a free ISOVER Technical Academy training course at