Partial Fill Cavity Wall Insulation – Design Guidance

To prevent thermal bridging Ballytherm boards should be fitted tightly to the edges of door and window openings. Lintels, which support the inner and outer leaf, should have internal insulation or be packed with Ballytherm insulation (figure 18).

Where radon barriers and cavity trays bridge the cavity, the insulation should be extended to the underside of the barrier or tray, and then continued immediately above it.

Further Advice & Information

For more information about Ballytherm products, technical advice, or guidance on the suitability of our products for your project, contact us at + 353 (0)49 95 27000,, email us at or use our contact form.

Floor Insulation