Felting & Liquid Overlay Systems for Flat Roofs
Flat roofs are exposed to constant weathering, standing water, UV radiation, and structural movement. Over time, these factors can cause traditional roofing materials to crack, blister, split, or fail—leading to leaks and costly internal damage. Felting and liquid overlay systems offer highly effective, long‑lasting solutions for restoring flat roofs without the disruption and expense of a full strip‑and‑replace.
Whether you’re dealing with an ageing felt roof, a failing single‑ply membrane, or a roof suffering from ponding water, modern overlay systems provide a seamless, durable, and cost‑efficient way to extend the life of your flat roof.
What Is a Flat Roof Overlay?
A flat roof overlay involves installing a new waterproofing system directly over the existing roof surface. This approach:
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Avoids the need to remove the old roof
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Minimises disruption to building operations
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Reduces waste and environmental impact
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Provides a fully renewed waterproofing layer
Overlay systems are suitable for a wide range of substrates, including:
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Traditional bituminous felt
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Asphalt
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Single‑ply membranes
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GRP
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Liquid‑applied systems
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Concrete decks
Felting Systems
Felting remains one of the most reliable and widely used methods of flat‑roof waterproofing. Modern felt systems are far more advanced than older bitumen roofs, offering improved durability, flexibility, and weather resistance.
Benefits of Modern Felting Systems
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Multi‑layer protection for enhanced durability
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Torch‑on or cold‑applied options depending on site requirements
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Excellent resistance to UV, heat, and standing water
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Strong reinforcement layers for added strength
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Long service life with manufacturer‑backed guarantees
Felting is ideal for roofs that require a robust, layered system capable of withstanding heavy foot traffic or demanding weather conditions.
Liquid Overlay Systems
Liquid‑applied roofing systems create a seamless, fully bonded membrane across the entire roof surface. These systems are cold‑applied, making them safe to install and suitable for areas where heat‑based methods are not permitted.
Benefits of Liquid Roofing Overlays
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Seamless waterproofing with no joints or weak points
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Highly flexible membranes that accommodate structural movement
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Ideal for complex details such as upstands, penetrations, and plant areas
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Excellent resistance to UV, weathering, and ponding water
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Fast installation with minimal disruption
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Long‑term warranties available
Liquid overlays are particularly effective on roofs with irregular shapes, multiple penetrations, or areas prone to standing water.
Why Choose an Overlay Instead of a Full Replacement?
✔ Cost‑Effective
Overlaying avoids the labour and disposal costs associated with stripping the existing roof.
✔ Minimal Disruption
The building can remain fully operational throughout the works.
✔ Environmentally Friendly
Less waste, fewer materials removed, and reduced landfill impact.
✔ Long‑Term Performance
Modern felting and liquid systems offer excellent durability and extended service life.
✔ Versatile
Suitable for most flat‑roof types and conditions.
Our Flat Roof Overlay Process
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Roof Survey & Assessment
We inspect the existing roof to determine suitability for an overlay and identify any underlying issues. -
Preparation & Repairs
Damaged areas, blisters, cracks, and weak points are repaired to ensure a stable base. -
Cleaning & Priming
The roof is cleaned and primed to ensure maximum adhesion of the new system. -
Installation of Felt or Liquid System
The chosen system is applied to create a fully waterproof, long‑lasting membrane. -
Detailing & Reinforcement
Upstands, edges, penetrations, and outlets are reinforced for complete protection. -
Final Inspection & Warranty
The finished roof is inspected and backed by a long‑term guarantee.
A Reliable, Long‑Lasting Solution for Flat Roofs
Felting and liquid overlay systems offer a proven, cost‑effective way to restore flat roofs and prevent future leaks. Whether your roof is showing signs of ageing or you’re looking for a long‑term waterproofing solution, our overlay systems deliver durability, performance, and peace of mind.