Why Flat Roofs Are Disappearing

Whether you’re extending, converting your garage, or building your dream home, everyone needs a good quality roof. Flat roofs are becoming a thing of the past, as pitched roofs provide structure and stability to any project. 

There is a reason that so many people prefer a pitched roof, one of them being the longevity of your roof. For the most part, a pitched roof will likely outlive any flat roofs due to the high-quality materials used during the construction process. Our lightweight roof tiles require little to no maintenance in comparison to traditional roofing materials, with special thanks to our BBA-backed 40-year weather penetration guarantee. 

Cons of Flat Roofing:          

 - Flat roofs require much more maintenance, therefore adding more day-to-day costs to the overall project life-cycle. 

 - With a flat roof extension, major alterations will need to be made due to the lowering of the ceiling.

 - Flat roofs are more likely to lose heat resulting in higher energy bills compared to pitched roofs, which are known for being more energy-efficient. 

 - Asphalt-based flat roofs tend to dry out and crack, which can be unsightly at first but then lead to leakage. 

 - Flat roof extensions often have a shorter lifespan than pitched roofs and more maintenance will be required to maintain the upkeep of the roof. 

 - On average, flat roofing systems typically offer guarantees of between 10 and 25 years. This covers all the main systems including: felt, asphalt, rubber, liquid, and GRP/fiberglass.

Pros of a Pitched Roofing: 

 - The aesthetic look of a pitched roof can add to the value of a property, providing a traditional and contemporary aesthetic.

- Pitched roofs have a longer lifespan than flat roofs. Rainwater flows down the slope of pitched roofs, eliminating the risk of water pooling on them increasing longevity, and decreasing the chance of leaks. 

- Pitched roofs also allow for higher ceilings, enabling more space beneath to be utilised. 

- Pitched roofs offer better protection against high-speed winds, heavy rains, and storm damage.

 - Pitched roofs offer better distribution of weight to the bearings of the building and the materials are generally more durable and weather resistant. 

What is Flat Roof Ponding?: Harmful Effects 

Flat roofs are notoriously known for ponding. Ponding is when water remains visible on a flat roof 48 hours after a rainfall. When water ponds on the flat roof, the standstill pool of water will compromise the integrity of the roof structure. Harmful effects start to arise when water sits on a flat roof for long period, such as the moisture breaking down the coating on the rooftop. 

Reasons why you should make the switch from a flat roof to a pitched roof: 

1. Damage to the Coating – Standing water affects the stability of the roof’s coating over time.  Gradually, the coating begins to break down under the harmful UV rays of the sun, which heats the ponding water on the rooftop. 

2. Destroyed Membrane – Damage occurs as ponding water makes its way through seams in the roofing membrane. As the pooling water heats up by the power of the sun, those areas become susceptible to leaks. 

3. Leaks and Collapse – Moisture enters weak points in the roofing system, leading to leaks into the interior parts of the commercial building. 

4. Invasive Plant Roots – The collection of dirt and water will likely cause vegetation, plants, and fungi to grow on the surface of the flat roof. 

5. Weakened Features – Consistent exposure to water promotes rust in the roof’s metal parts and damages the roof’s concrete features. 

The Solution  

The slope angle of a pitched roof makes it much easier for rainwater to drain down the side of the roof. Pitched roofs can cost more than a flat roof and take longer to install. However, in exchange for the added expense, you will receive a roof with an effective water drainage system that boasts a longer lifespan. 

Contact Britmet today for more information about our lightweight roofing materials. 

Source List: 

https://roof-maker.co.uk/inspiration/blog/which-is-best-a-pitched-or-flat-roof-extension/  
https://restorationmasterfinder.com/restoration/flat-roof-ponding-harmful-effects/ 
https://www.rjevansroofing.com/blog/how-long-is-a-flat-roof-guaranteed for/#:~:text=A%20flat%20roof%20is%20guaranteed,%2C%20liquid%20and%20GRP%2Ffibreglass.