ARC T-Barrier Pitched Roof TBR125/25 125mm Party Wall Cavity (Pack of 6) by ARC Building Solutions

The ARC T-Barrier Pitched Roof TBR125/25 is designed for installation at the head of a 125mm party wall cavity where the brickwork meets a pitched or flat roof. A fully tested, IFC-certificated cavity barrier (IFCC 1728), it sits in compression directly beneath the roofing membrane, delivering up to four hours fire integrity (240 minutes) and up to two hours fire insulation (120 minutes) to EN1366-4. Complies with NHBC 2017 clause 7.2.16. Supplied in a pack of 6 x 1200mm lengths.

Manufactured from non-combustible rockfibre mineral wool with a thermal conductivity of 0.037 W/mK, the T-shaped profile is held entirely by compression between the two cavity leaves at the head of the 125mm party wall — no mechanical fixings are needed. The stalk ensures the barrier is correctly positioned under the roofing membrane. A minimum 25mm clearance is required between the top of the wall and the underside of the roofing membrane for this product to be installed correctly.

Key facts:

• Party wall cavity: 125mm
• Pack of 6 x 1200mm lengths
• Third-party certificated by IFC — certificate number IFCC 1728
• Up to four hours fire integrity (240 minutes), tested to EN1366-4
• Up to two hours fire insulation (120 minutes)
• Complies with NHBC 2017 clause 7.2.16
• Rockfibre mineral wool — thermal conductivity 0.037 W/mK
• Compression fit only — no mechanical fixings required
• Minimum 25mm clearance required between wall top and roofing membrane

For party wall fire barriers in the masonry wall cavity below eaves level, see the ARC T-Barrier Masonry TBM100/100 range with the same IFCC 1728 certification.

Installation info:

Install once the 125mm party wall brickwork is complete, before the roofing membrane is laid. Place the barrier at the head of the cavity with the stalk positioned correctly beneath the membrane. Hold in place using compression between the cavity leaves — no adhesive or mechanical fixing is required. Handle carefully to avoid damaging the mineral wool. Butt successive lengths tightly with no gaps.