Debunking Flat Roof Myths: Your 2025 Guide to Understanding Costs, Construction & Lifespan

Whether you’re considering a flat roof for your home extension, conservatory, orangery, garage conversion or a commercial building, it’s essential to understand that modern flat roofs provide many advantages and design opportunities. 

That said, despite their growing popularity, there are also plenty of myths and misleading information regarding performance, durability, energy efficiency and more. In this article, we debunk some of the myths that surface online, and provide a detailed look at flat roof construction.

Debunking Common Flat Roof Myths

Myth #1: Flat Roofs Are More Prone to Leaks

One of the most prevalent myths is that flat roofs are vulnerable to leaks due to their near non-existent pitch, but that’s simply not true. Modern materials like PVC, TPO, single-ply and EPDM (among other materials) are designed to be watertight. A poor installation can certainly leave homeowners riddled with issues, however, that’s exactly why any installation should be carried out by experienced professionals like High-Tech Membrane Roofing Ltd. We can ensure all seams are perfectly sealed and that adequate drainage is in place whilst we utilise leading-edge materials, such as Protan, which delivers long-lasting performance, even in harsh weather conditions. Protan membranes are also designed to resist UV rays, chemicals and temperature fluctuations, ensuring that the roof remains intact and functional for many years. 

Myth #2: Flat Roofs Are Not Suitable for Homes 

You probably only have to look along your street to see this is not the case. Contrary to the notion that flat roofs are only for commercial properties, many modern homes feature flat roofs due to their sleek, contemporary appearance. They can be particularly advantageous when adding green roofs or rooftop patios, enhancing both the aesthetic and functional space of a home. The reason there are so many flat roofs installed in UK homes comes back to durability, reliability and long-lasting performance.

Myth #3: Flat Roofs Are Expensive to Install and Maintain 

While the initial installation cost of a flat roof can vary from about £50 to £110 per square meter, according to Checkatrade, the investment is often justified by the roof’s longevity and lower maintenance costs. For example, a felt roof might average around £65 per m², but more durable materials like PVC, although slightly pricier, can last over 20 years with proper care, offering better long-term value.

Myth #4: Flat Roofs Have a Short Lifespan 

Many believe that flat roofs simply won’t last as long as other types of roofing. However, the lifespan of a flat roof largely depends on the material used and the quality of maintenance. As we’ve discussed, felt roofs may last 10-15 years, while materials like PVC can exceed 20 years if regularly inspected and properly maintained.

Myth #5: Flat Roofs Negatively Affect Insurance and Property Value 

Owning a flat roof can alter insurance dynamics, as premiums might vary based on the perceived risks associated with flat roofing systems. However, declaring the roof type and ensuring it is well-maintained will mitigate these concerns. Additionally, homes with flat roofs can be appealing in the property market, especially if the roof is equipped with modern materials and features like green roofs or solar panels.

Myth #6: Flat Roofs Offer No Environmental Benefits 

Another one that’s simply not true. Flat roofs can significantly enhance a building’s sustainability. They are the ideal platform for green roofs, which provide excellent insulation, reduce urban heat, manage stormwater and support biodiversity. Flat roofs are also perfect for solar panel installation, which can lower energy costs and increase the building’s value.

Understanding Flat Roof Construction and Materials

With any flat roof construction, it’s crucial to carefully consider the best materials for the task at hand, as each offers unique benefits and is suitable for different environmental conditions and building needs. 

Single-ply Flat Roofing

Single-ply roofing materials continue to lead the way in modern flat roofing technology, offering a combination of durability, cost-effectiveness and ease of installation, making these solutions highly suitable for commercial and residential buildings. 

PVC (Polyvinyl Chloride)

PVC roofing membranes are known for their longevity, durability and resistance to water, fire, and chemicals. They are particularly suitable for restaurants and other businesses that emit oils and fats due to their resistance to biochemical compounds. A PVC roof can last more than 20 years with proper maintenance. We’ve touched on Protan PVC, which is recognised for its sustainability and ability to withstand harsh environmental conditions, including UV rays and biochemical emissions from businesses like restaurants. Its flexible and robust nature makes it suitable for various architectural styles, ensuring a reliable waterproofing solution lasting over 20 years with proper maintenance.

EPDM (Ethylene Propylene Diene Monomer)

EPDM is a synthetic rubber material that is extremely durable and offers excellent resistance to weathering, abrasion, and temperature extremes. It is easy to install, repair, and maintain, making it a cost-effective option for large commercial roofs. Having no seams to leak is also a major advantage, however, this type of flat roofing can come at a higher price point due to the complexity of the material, which can drive up installation costs.

TPO (Thermoplastic Polyolefin)

TPO roofing is another favourite for residential and commercial buildings due to its excellent resistance to UV rays and chemical exposure. It is also highly flexible, which makes it resistant to tears, punctures and impacts. Its white reflective surface helps reduce cooling costs, making it an energy-efficient option.

Other Flat Roofing Materials:

GRP (Glass Reinforced Plastic) and Fibreglass

GRP, commonly known as fibreglass, is moulded to fit the roof. It is highly durable, waterproof, and virtually maintenance-free. GRP is particularly popular for its adaptability in terms of colours and finishes, as well as its robustness against walk-on use.

Mineral Felt

Mineral felt roofing is a traditional material that involves layers of bitumen-soaked paper or fibreglass coated with a mineral granular finish. It is one of the most cost-effective materials for flat roofs and is easy to repair and maintain, though it requires more maintenance to ensure longevity.

Torch-On Felt

Torch-on felt involves layers of modified bitumen that are melted onto the roof surface with a torch. This creates a highly impermeable seal that offers excellent waterproofing capabilities. It is ideal for roofs that need extra protection against extreme weather.

Mastic Asphalt

As a seamless, waterproof material, mastic asphalt provides a durable wearing surface. It can be used on flat roofs, basement waterproofing and even under road surfaces due to its versatility. Its longevity and the ability to form a solid, impermeable mass make it a reliable choice for many builders.

Liquid-Applied Resin

Liquid-applied resin systems are also rising in popularity for certain projects, providing a seamless, fully bonded waterproof membrane that excels in versatility and durability. Applied as a liquid, these polymers—typically polyurethane or polyester resins—cure to form a tough, elastic coating that adheres flawlessly to a variety of substrates. This method is ideal for roofs with complex geometries intricate details, or where traditional membrane application is impractical. Beyond roofing, liquid-applied resins are also ideal for waterproofing balconies, terraces and indoor wet areas. 

Green Roofs

Green roofs are part of an eco-friendly building trend, consisting of a layer of vegetation planted over a waterproofing membrane. They offer excellent insulation, help manage rainwater, and increase biodiversity in urban areas. They can also improve the aesthetic appeal of a building and potentially increase its property value.

Quickfire FAQs

Are flat roofs cheaper than pitched roofs? 

Generally, yes. Flat roofs are less expensive to install than pitched roofs due to less structural complexity and fewer materials. Ultimately, less surface area equals less material and labour.

How do you prevent water pooling on a flat roof? 

Good design includes slight slopes and proper drainage systems to prevent pooling and ensure water is channelled away efficiently.

What is the best material for a flat roof in a cold climate? 

PVC is highly recommended for cold climates due to its durability and resistance to cracking in freezing temperatures.

Why Choose High-Tech Roofing?

At High Tech Roofing, we specialise in providing durable, high-quality flat roofing solutions tailored to commercial and residential properties. Our expertise ensures that every flat roof we install maximises performance and aesthetics. Contact us today to learn how we can enhance your building with a reliable, modern, flat roof that stands the test of time.