Maximum thermal performance
222mm SIP Panel Specification
Our highest-performance panel: a 200mm PIR core between two 11mm Sterling OSB/3 boards for 0.106 W/m²K. Built for low-energy and Passivhaus-influenced projects that aim to go beyond common elemental U-value targets and minimise heating demand.
Panel build-up
Every UltraSIPs panel bonds a rigid PIR insulation core to two structural Sterling OSB/3 boards, creating a single composite panel that is both the insulation and the load path — no separate timber frame to insulate around, and far fewer thermal bridges than stud construction.
This 222mm panel uses a 200mm PIR core (thermal conductivity λ = 0.022 W/mK) faced with 11mm OSB (λ = 0.13 W/mK). The resulting U-value of 0.106 W/m²K is calculated to BS EN ISO 6946 — the same method behind our interactive U-value calculator, where you can model other core and OSB combinations.
Panels are manufactured up to a maximum board size of 2440mm × 1220mm.
Indicative Part L U-value check
Comparison of this panel's 0.106W/m²K U-value against common England & Wales Part L 2021 elemental U-value targets. This panel is below the indicative targets shown below.
Fabric U-value comparison only. This is not whole-building compliance or Building Control approval. Junctions, openings, ventilation, fire linings and the wider specification should be confirmed with your designer, engineer or Building Control. Fire resistance is achieved with the appropriate internal lining (for example plasterboard) and should be specified per project.
Where the 222mm panel fits
Best for
- Low-energy, Passivhaus-influenced walls and roofs
- Projects targeting very low heating bills and future-proofed fabric
- Rooms where you want to go beyond common elemental U-value targets
Consider a different panel when
Tight wall zones where the extra depth is a problem — the 172mm panel may already meet the project’s required elemental U-value target.