Hygrothermal modelling using WUFI software recently compared conventional timber-framed walls with bulk insulation against timber-framed walls incorporating Kingspan Kooltherm rigid insulation, either externally as Kooltherm K12 Framing Board or internally as Kooltherm K17 Insulated Plasterboard. The results showed a lower predicted mould growth risk where rigid insulation was used compared to traditional bulk insulation.

Kooltherm K12 Framing Board installed outside the frame, helps keep the framing warmer, reducing internal moisture levels and the likelihood of mould developing. Internally, Kooltherm K17 Insulated Plasterboard helps slow water vapour moving into the wall structure, also reducing moisture accumulation and supporting healthier indoor conditions.

In New Zealand, the availability of 35mm Kooltherm K17 Insulated Plasterboard with bracing capability adds another dimension to wall design. It allows designers to achieve thermal performance, internal lining, and structural bracing contribution within a single system. This can simplify wall construction while supporting comfort, durability, and compliance in modern residential living spaces.

Rather than increasing mould risk, high-performance rigid insulation when properly designed into wall systems, can help manage moisture, improve comfort, and contribute to long-term building performance.

For access to the full Hygrothermal modelling report, or technical design assistance, reach out to the Kingspan Thermakraft's Technical Team, [email protected].