Harmer Building Drainage

Trusted Drainage Solutions. Engineered for Performance.

Harmer Building Drainage provides a comprehensive range of high-performance drainage solutions designed to manage water safely and efficiently both inside and outside the building envelope. Combining robust engineering with proven reliability, the portfolio supports architects, contractors and specifiers with systems for roof drainage, floor drainage, above and below ground applications, and external landscaping projects. Manufactured from premium materials including aluminium, cast iron and stainless steel, Harmer products are designed to meet the demands of modern construction. The range delivers long-term durability, ease of installation and dependable hydraulic performance across commercial, residential, healthcare, education and public sector developments.

Aluminium Roof Outlets

Harmer Aluminium Roof Outlets provide a lightweight, high-performance solution for draining flat roofs, balconies, terraces and podium decks. Manufactured from corrosion-resistant LM6 aluminium, the range includes vertical, horizontal and parapet outlets, allowing designers to accommodate a wide variety of roof constructions and drainage layouts. Available with spigot or threaded connections and a range of leaf guards, gravel guards and insulation clamp options, the system provides flexibility for both new-build and refurbishment projects. Engineered for excellent flow performance and long-term durability, Aluminium Roof Outlets combine reliable drainage with simplified installation and maintenance.

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Cast Iron Roof Outlets

Harmer Cast Iron Roof Outlets are designed for projects where exceptional strength, durability and fire performance are critical. Manufactured from robust cast iron, the range includes vertical, horizontal and parapet outlet configurations, suitable for flat roofs, green roofs, inverted roofs and roof terraces. Available with a comprehensive range of accessories including membrane clamps, gravel guards and inspection chambers, the system offers secure integration with a variety of waterproofing solutions. Combining high flow capacity with excellent impact resistance, Cast Iron Roof Outlets deliver dependable roof drainage for demanding commercial and public sector environments.

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Modulock Pedestals

Harmer Modulock Pedestals provide a versatile support solution for paving and decking applications on roof terraces, balconies and podium decks. The adjustable system accommodates a wide range of finished floor heights, enabling installers to create level surfaces with drainage, waterproofing and service installations concealed beneath. Available in multiple pedestal heights and configurations, the range can support natural stone, concrete paving slabs, porcelain tiles and decking systems. Precision-engineered for strength and stability, Modulock Pedestals help create accessibility and visual appeal in external spaces where effective drainage performance is a priority.

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Modulock Channel

Harmer Modulock Channels are designed to manage surface water efficiently within landscaped and paved environments. Developed to integrate seamlessly with paving support systems and external hard landscaping schemes, the range provides effective linear drainage for podium decks, terraces, balconies and pedestrian areas. Available in a variety of channel widths, depths and grating options, Modulock Channels allow designers to balance hydraulic performance with architectural appearance. Durable, easy to install and compatible with other Harmer drainage solutions, they provide a practical and visually discreet method of controlling surface water.

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SML Below Ground

Harmer SML Below Ground extends the performance benefits of cast iron into buried drainage applications, providing a durable solution for underground foul and stormwater networks. The system comprises pipes, fittings, bends, junctions and access components designed to withstand external loads and challenging site conditions. Offering excellent resistance to impact, fire and environmental exposure, SML Below Ground delivers a long service life with minimal maintenance requirements. Its robust construction makes it particularly suitable for commercial developments, public buildings and infrastructure projects where reliability and durability are paramount.

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Cast Iron Floor Drains

Harmer Cast Iron Floor Drains are engineered to provide reliable and long-lasting floor drainage in demanding environments. The range includes circular and square drain bodies, alongside a variety of grating designs, outlet configurations and load classifications to suit different applications. Manufactured from durable cast iron, these drains offer excellent resistance to impact, wear and heavy traffic, making them ideal for plant rooms, service areas, commercial kitchens, loading bays and external locations. Designed for effective water removal and easy maintenance, Cast Iron Floor Drains combine robust performance with proven longevity.

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Shower Outlets

Harmer Shower Outlets provide efficient drainage solutions for modern bathroom, wetroom and accessible washroom installations. The range includes horizontal and vertical outlet configurations, together with options suitable for tiled, vinyl and resin floor finishes. Designed to achieve high flow rates while maintaining a low-profile installation, the outlets help create attractive, level-access shower environments. Available with a selection of grating styles and finishes, Harmer Shower Outlets combine practical performance with contemporary aesthetics, making them suitable for residential, healthcare, hospitality and commercial applications.

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