ARC T-Barrier Foundation

The ARC T-Barrier Foundation is a T-shaped rockfibre mineral wool cavity barrier for masonry foundation construction, sealing the cavity at the base of the party wall where it meets the ground-floor slab or foundation level. It is fully tested and third-party certificated by IFC (certificate number IFCC 1728), achieving up to four hours fire integrity and up to two hours fire insulation at foundation level — the highest rating in the T-Barrier range.

Products are manufactured from non-combustible rockfibre mineral wool (thermal conductivity 0.037 W/mK) encapsulated in high-strength polythene, with an integral DPC included as standard, eliminating the need for a separate damp proof course at this detail. The T-shaped profile self-locates in the cavity with no mechanical fixings required — a friction fit in the external cavity holds the barrier securely as the masonry is laid. The range covers party wall widths from 75mm to 150mm and external cavity widths from 75mm to 150mm.