T-Pren was developed over 25 years ago in Europe to overcome expansion problems in metal gutters. The daily and seasonal thermal cycling causes metal gutter linings to expand and contract, and if expansion joints are not provided this movement will cause the metal to crack and so the gutter to leak.

The traditional solution was to use the metal in short lengths, increasing the need for outlets, or incorporate expansion steps into the gutter. However, the height of the parapet may not be able to accommodate the number of steps required or, in the case of masonry, it may not be possible to cut the steps.

T-Pren was developed to overcome these problems by providing a waterproof expansion joint, which reduces the number of outlets and eliminates the need for steps. Lead T-Pren Plus was developed to overcome objections to the appearance of the black neoprene. It has a unique protective cover strip that maintains consistent metal appearance across the joint and prevents damage from foot traffic and building materials.

T-Pren consists of two metal strips connected by a high quality neoprene expansion joint. The joint is formed on both sides of the metal during vulcanisation of the neoprene, and for lead T-Pren Plus a separate cover strip is vulcanised on top of the neoprene.

The strength of the double vulcanised joint has been proved by the 25 years of service without failure.