Housing Wed, Nov 4, 2026 8:45 AM
Flat roof drainage is commonly project-specific, with different roof constructions, waterproofing systems, building designs, balconies and terraces, all requiring individually tailored solutions.
Harmer Aluminium Roof Outlets from Alumasc have been developed to meet these varied requirements, across commercial, residential and public sector construction.
Designed for use with in-situ concrete, timber and lightweight metal deck roof structures, the Harmer aluminium range is compatible with warm, cold and inverted roof constructions.

The outlets connect to continuous waterproofing systems including single ply membranes, high-performance built-up felt, mastic asphalt, hot melt and liquid-applied, allowing consistency of drainage across a wide range of roofing applications.
They are manufactured from precision cast LM6 aluminium silicon alloy, are lightweight, corrosion resistant and fully recyclable. Various grate options are available to suit the intended roof use.
Spigot and screw outlet configurations are available, allowing designers to select the most appropriate connection method for each project. Spigoted outlets are most commonly used, where the slab depth allows. For applications where there is a deeper build up and no joints, extended spigots can be specified.
Harmer Aluminium Roof Outlets also support modern high-rise construction. An aluminium threaded spigot adaptor option provides an A1 fire-rated connection between threaded aluminium roof outlets and a wide variety of Alumasc aluminium downpipes and other systems. This creates a fully compatible non-combustible drainage solution, compliant with current fire safety requirements for high-rise construction, and also eliminates the need for mechanical joints within the concrete slab.
Harmer Roof Outlets and Alumasc aluminium downpipes are both BBA approved powder coated, making the system A2-s1, d0 fire-rated. Products are A1 fire-rated if not painted.
Aluminium offers an expected service life of up to 40 years in rural and suburban environments, and up to 25 years in industrial or marine locations.
In association with Alumasc Water Management Solutions
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