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What is the Difference Between a Pitched Roof and a Flat Roof?

Within this blog, we will explore the definitions, advantages of and differences between pitched and flat roofing. Whether you are looking at residential or commercial roofing options, the type of roof you pick can affect the aesthetics of your project, as well as the function and value. Picking the correct type of roof is a key decision with your project planning and we hope this blog helps you to make the right choice for you.

What is a pitched roof?

A pitched roof slopes downwards, this will typically be in two parts from a central ridge. Nowadays, these will be built using timber or steel as a formwork surface. However, in earlier times before modern construction methods, you would have seen the pitched roof made entirely from a timber structure.

They may seem simple but there are various types of pitched roof, including mono-pitch roof/lean to, duo-pitch/gabled roof, hipped roof, Mansard roof, gambrel roof or dormer roof among others.

Pitched roofing can be seen as early as the temples of ancient Greece. Since then, it has been a staple roofing design used in architecture seen in Northern Europe as well as America. Pitched roofs are still a very common and popular choice within both domestic and commercial buildings.

What is a flat roof?

You may be thinking that you know what a flat roof is. Flat, right? However, the reality is that flat roofs do have a slight slope of around 5°. This allows rainwater to run off to the lower side.

Flat roofs can be constructed in a range of materials. Firstly, let's consider the structural deck. The best material is concrete, but it is unusual to see this in domestic properties, more often, the material used is timer board, plywood or oriented strand board (OSB).

We then need to consider the covering. Most common in the UK is reinforced bitumen membranes (RBM) or Torch on Felt. This is normally comprised of three layers of material to form a waterproof membrane.

In addition to waterproofing, some RBM roofs will need a protective layer, which is often formed using gravel or shingle. This makes the roof weatherproof against high winds.

Other materials used may be asphalt, single ply, ethylene propylene diene monomer (EPDM), glass reinforced plastic (GRP), green roof systems or lead.

When we look back to ancient history, flat roofs are commonly seen in regions where there is less rainfall and snowfall. They came into widespread use in Europe and America in the 19th century due to the increase of waterproof materials which made flat roofing more viable in wetter weather conditions. In current times, flat roofing is more common on office buildings and larger commercial buildings, such as warehouses. However, they can be seen on residential homes too.

What are the key benefits of a pitched roof?

One of the key benefits of a pitched roof is the durability of the design. Since the roof is sloped, gravitational forces will naturally drain any rainfall. This makes them more durable in adverse weather conditions as well as being able to withstand day-to-day precipitation. Their drainage reliability and durability are both great benefits of a pitched roof.

Although the selection of pitched roofing materials and ensuring a high level of professional installation will play a part here, if you get these factors right, you will see a much longer lifespan from your pitched roof than other designs. This is also thanks to the efficient drainage system which ensures water pooling does not occur and therefore, there is less likelihood of severe damage or high-level maintenance on a pitched roof.

One of the biggest benefits, and even used as a selling point, of a pitched roof is the loft space it creates. This space can be used for storage or, if properly insulated, can also create an additional room that can be used as a bedroom, office or playroom. This additional space can add value to your home, something that other roofing designs, such as a flat roof, cannot offer.

The next benefit to consider when thinking about pitched roofing is the simple maintenance. As you can go into the loft space, your chosen roofing professional can check the beams and roofing for any water damage easily. This allows for easy and regular maintenance checks, providing you with peace of mind that your roof is safe and secure.

What are the key benefits of a flat roof?

When discussing the benefits of flat roofing, one that you will often hear is the expense. A flat roof is quicker to install and, therefore, there is less labor cost involved. If keeping costs to a minimum is important to you, then it is highly likely that a flat roof will always come in at a lesser cost than a pitched roof.

Cost isn't the only factor to consider when deciding which roofing type is best for you. You will also want to think about the environmental impact of the roof you have installed. Eco Friendly green roofing works well on a flat roof. In fact, most would say it works best on a flat roof. Eco Friendly roofing is a great way to soak up rainfall, support wildlife habitats and increase the longevity of your roof.

We are seeing more flat roofs being installed due to their contemporary design. When constructed with modern materials, flat roofs can have a very contemporary feel that can add aesthetic appeal to both domestic and commercial properties. Roofing materials may include EPDM, TPO or PVC membrane roofing. We would recommend investigating the best flat roofing supplies near you.

How do the two compare?

Cost is often one of the biggest and most important factors when considering a domestic or commercial build. Whether you're a homeowner or project manager, you will want to consider how much each option will cost you. As mentioned above, flat roofing will usually be the more affordable option. Of course, this will depend on materials used and the cost of labor in your area. Do your research to make sure you are getting the best price.

Longevity and ongoing maintenance costs are also a hugely important factor. Although more expensive, the self-draining design of the pitched roofing means that it is likely to have a longer life span and a lower need for maintenance. So, whilst the cost is more upfront, over a longer time period, you can expect to see lower maintenance costs.

Design is subjective and everyone will have a different view on what looks good, this makes it difficult to compare the two without giving a biased judgment based on our own taste! When considering design, you will need to consider the design of roofing in your area, or even on your current home/building if you are planning to extend. This is one of the deciding factors for local authorities when looking at planning requests, therefore, having a design that is in keeping with the local area will always work in your favor. You may also want to consider which design will have the best resale value. If you are looking to build a family home, having loft space may be seen a large advantage to some families. 

Published at: 07-07-2022

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