When it comes to protecting a building from water ingress, weathering, and structural deterioration, roofing integrity is essential. In recent years, liquid roofing systems have become a popular choice for both new installations and refurbishments, thanks to their versatility, durability, and seamless waterproofing capabilities. One of their biggest advantages is how effectively they can work alongside existing felt and metal roofing systems, creating a reinforced, long-lasting solution without the need for a full roof replacement.
What Is a Liquid Roofing System?
A liquid roofing system is a cold-applied, resin-based coating that forms a seamless, fully adhered waterproof membrane. Once cured, it becomes a flexible, durable surface capable of withstanding UV exposure, temperature fluctuations, ponding water, and foot traffic. These systems include materials such as polyurethane, PMMA, and liquid rubber, each offering distinct benefits depending on the project requirements.
For property owners seeking a cost-effective, long-lasting upgrade to an existing roof, liquid systems provide a fast and efficient solution that significantly extends roof life without extensive disruption.
How Liquid Systems Work with Felt Roofing
Traditional felt roofing (also known as built-up roofing) remains common across residential, commercial, and industrial structures. While felt can perform well for many years, it can become prone to aging and often difficult to use on very intricate detailing. This is where liquid systems step in.
1. Seamless Waterproofing Over Existing Felt
Liquid coatings are applied directly over the existing felt surface once cleaned and primed. This process eliminates weaknesses at joints and overlaps, creating a continuous membrane that blocks water penetration.
2. Reinforced Durability
When combined with reinforcement fleece, liquid coatings dramatically increase tensile strength. This is particularly important for older felt roofs that may have weakened areas or surface irregularities.
3. Cost-Effective Refurbishment
Liquid systems remove the need to strip back old felt, reducing labour costs and minimising waste. This makes them an environmentally friendly and budget-friendly option for extending the life of a felt roof by up to 20–25 years.
4. Improved Flexibility
Felt roofs can struggle with movement caused by thermal expansion. Liquid coatings, however, remain flexible year-round, preventing cracking or splitting as temperatures shift.
How Liquid Systems Work with Metal Roofing
Metal roofing systems are known for their strength and longevity, but they can suffer from challenges such as corrosion, loose fixings, leaks at seams, and noise from expansion. Liquid roofing provides an effective way to enhance the performance of metal structures without costly panel replacements.
1. Enhanced Corrosion Resistance
Many liquid systems include rust-inhibiting primers that protect metal substrates from ongoing corrosion. This treatment effectively seals the surface and prevents further deterioration.
2. Seam Encapsulation
Metal roofs typically rely on mechanical fixings and overlapping panels. Over time, these joints can loosen or allow water ingress. Liquid coatings encapsulate seams and fixings in a seamless membrane, eliminating common leak points.
3. Temperature and Movement Tolerance
Metal expands and contracts significantly with heat. A high-quality liquid membrane stretches with the substrate, accommodating this movement while maintaining a seal.
4. Noise and Thermal Regulation
Some liquid coatings improve insulation and reduce noise levels during rainfall or thermal movement, creating a more stable and comfortable indoor environment.
The Combined Benefits for Felt and Metal Roofing
Whether applied to felt or metal roofing, liquid systems offer numerous universal advantages:
• Rapid installation with minimal disruption
• Cold-applied safety, no flames or hot works required
• Seamless waterproofing with no joints, overlaps, or weak points
• UV and weather resistance for year-round durability
• Extended roof lifespan without full replacement
• Compatibility with complex roof shapes, detailing, and penetrations
Final Thoughts
Whether on its own or as well as, liquid roofing systems have revolutionised the way felt and metal roofs are maintained and upgraded. By forming a durable, seamless, and flexible membrane, they provide long-term protection and exceptional performance across a wide range of environments. Whether you’re looking to repair an ageing felt roof or reinforce a metal system prone to leaks and corrosion, liquid roofing offers a cost-effective, high-performance solution that maximises the lifespan of your existing structure.
