ARC Additionally, it provides an effective edge seal around the party wall cavity, helping to achieve a zero U-value. It is easily installed as the timber frame is erected. Polythene flanges are present to allow the barrier to be stapled back to the timber while the brickwork progress, when a compression fit ensures the barrier stays in place. For runs of more than 1.2m, lengths of T-Barrier should be butted tightly together, with care taken to ensure there are no gaps. Key features: Up to four hours fire integrity. Seals edge of party wall cavity. Up to three times more effective as an edge seal than conventional systems. Reduces flanking noise. Zero U-value at party wall can be achieved. Minimises thermal bypass. Available in different Sizes. Easy to install. Green Guide rating of A+.