GRP Through Wall / Parapet Outlet Trim

The GRP Through Wall / Parapet Outlet Trim is a pre-formed drainage component used where a flat roof sheds water laterally through a parapet wall rather than vertically through the roof deck. It creates a waterproof channel through the full thickness of the parapet, directing rainwater from the roof surface to the outer face of the wall and into a downpipe or hopper below.

Parapeted flat roofs without adequate through-wall outlets are a common cause of ponding and water damage - the parapet effectively creates a dam that prevents surface water from draining naturally. This trim provides the correct solution: a purpose-made GRP outlet that integrates with the roofing laminate on the roof side and provides a clean, weatherproof exit point on the wall face. It is compatible with GRP, liquid-applied, and single-ply roofing systems, and is fixed using PU adhesive as part of the standard trim installation process.

GRP roofing trims provide a practical, durable, and aesthetically pleasing solution for finishing fibreglass flat roofs and for other domestic and industrial applications. With their superior strength, resistance to the elements, and ease of installation, they help ensure a long-lasting, weather-tight roofing system. By combining functionality with modern design, GRP trims offer an excellent way to enhance the performance and appearance of fibreglass roofs.