Flat roof vs pitched roof cost

This cost guide takes a closer look at flat roof vs pitched roof costs, including the pros and cons of each roof type, the differences in aesthetics, and the cost of extending each type of roof.

When it comes to roofing, flat and pitched roofs are two of the most common options for homes and extensions in the UK. Each type of roof has its own set of advantages and disadvantages, while the cost of installation and maintenance varies greatly between the two.

Keep reading for our deep dive into pitched roof v flat roof costs.

Flat roof vs pitched roof cost differences

When deciding between a flat roof vs a pitched roof, it’s important to consider the upfront cost of their installations as well as their long-term maintenance and repair costs.

Additionally, make sure you choose a professional roofing expert who’s checked, trusted, and verified. Making sure the job is done properly the first time will save you additional costs for repairs in the long term.

Find out how to choose the perfect local roofer.

Flat roof costs

The cost of a flat roof typically ranges from £50 – £110 per m2, depending on the materials used.

For example, a felt roof might cost an average of £65 per m2, while a more durable EPDM rubber roof might cost between £80 – £100 per m2.

Other factors that impact the cost of a flat roof include the size of the roof, the level of access required to build it, and the complexity of the design.

Pitched roof costs

The cost of pitched roofs are often higher than flat roofs – again depending on the materials used. Consequently, prices range from £120 – £275 per m2.

Common materials for pitched roofs include slate, concrete tiles, and clay tiles (with slate being the most expensive option). Other factors that will impact the cost of a pitched roof include the size and complexity of the roof, as well as the location of your property.

Related content: Read our guide on the cost to replace a flat roof with a pitched roof for more information.

NB: It’s important to note the above estimates are for the cost of your roof installation only and don’t include the cost of ongoing maintenance and repairs.

Flat roof vs pitched roof extension cost

The cost of extending a flat roof vs a pitched roof depends on the size of the extension, the materials used, the complexity of the job, and what tradesperson or company you use. However, there are some key differences worth exploring below.

Flat roof extension cost

The cost of extending a flat roof will depend on the size of the extension, the types of materials used, the overall design (e.g. any skylights or windows) and whether you used an architect or not.

In general, extending a flat roof is less expensive than extending a pitched roof due to its less complex design options and the lower cost of materials. However, flat roofs require more frequent maintenance and repairs, which increases their long-term costs. This is because they’re more susceptible to leaks and water damage.

It’s also worth noting the final cost for a flat roof extension is based on the level of access needed to undertake the construction and any additional structural work that’s required to support the new roof.

Taking all that into account, the average cost of a flat roof extension is £52.5k.

Related content: Read more about flat roof extensions in our cost guide.

Pitched roof extension cost

As with any construction project, the cost of extending a pitched roof depends on the size, height, and complexity of the job. It’s also down to the type of materials used and whether the extension requires additional structural work, such as new beams or support, which adds to the overall cost of the project.

Taking all this into account, the average cost of a pitched roof extension is around £60k.

Slate is the most expensive roofing material for a pitched roof with prices ranging from £160 to £275 per square metre, while concrete or clay tiles can cost between £120 to £230 per square metre.

Related content: Read our guide on roof tile replacement costs for more information.

NB: While pitched roofs tend to require less maintenance than flat roofs, they may still require occasional repairs or replacement of damaged tiles or slates. This should also be factored into the overall cost of a pitched roof extension.

Additional costs

Other costs to take into consideration when installing a roof or roof extension include:

• Carpenter labour (per day): £300
• Roofer labour (per day): £300
• Professional structural designs (per hour): £50
• Planning permission (England): £210
• Planning permission (Wales): £190

Flat roof vs pitched roof: Pros and cons

Before we get started, it’s worth taking a look at the pros and cons of flat and pitched roofs.

Flat Roof

Despite popular belief, flat roofs aren’t ruler-straight; they’re just not as pitched as other types. Typically, they have no ridge and a rise of around 10 degrees to allow rainwater runoff and stop potential ‘pooling’ or flood damage.

Pros

• Lower cost of installation compared to pitched roofs
• Can be used as a rooftop garden or outdoor space
• Easy to access for maintenance and repair
• Suitable for modern and minimalist architectural styles

Cons

• Limited lifespan due to constant exposure to the elements
• Greater risk of leaks and water damage
• Lack of natural drainage, leading to potential water buildup
• Requires regular maintenance and upkeep to prevent damage

Pitched Roof

Unlike flat roofs, pitched roofs have a middle ridge and two sloped sides that create the ‘pitch.’ The degree of the rise varies depending on the design of the roof, but 45 degrees is pretty standard.

Pros

• Longer lifespan than flat roofs
• Better natural drainage and water runoff
• Classic and traditional aesthetic appeal
• More durable and weather-resistant, especially in areas with heavy snow or rainfall

Cons

• Higher cost of installation compared to flat roofs
• More difficult to access for maintenance and repairs
• Limited use for outdoor space or rooftop garden
• Not suitable for modern or minimalist architectural styles

Flat roof vs pitched roof: Aesthetics

The aesthetic appeal of flat roofs vs pitched roofs is a matter of personal preference around what architectural styles you like.

For example, homeowners often favour flat roofs for their modern and minimalist properties, which suit the versatility and architectural qualities of these roof types. They’re also popular because they allow you to build a rooftop garden or outdoor living space, which adds to the overall visual appeal (and square footage) of a home.

On the other hand, pitched roofs are viewed more traditionally with various classic designs and tile options. Learn more by reading our blog on Roof ideas: Inspiring architecture for the perfect roof design.

Quick summary (TL:DR)

To summarise, the average price difference between a flat roof and a pitched roof is as follows:

• Flat roof cost: £50 – £110 per m2.
• Pitched roof cost: £120 – £275 per m2.
• Flat roof extension cost: £52.5k.
• Pitched roof extension cost: £60k.

When considering flat roof vs pitched roof costs, it’s important to weigh up the pros and cons of each type of roof, as well as its aesthetic appeal and the associated extension options.

While flat roofs are less expensive to install, they require more maintenance and have a shorter lifespan than pitched roofs. Conversely, pitched roofs have a longer lifespan and better natural drainage but are often more costly to install and maintain.

Additionally, it’s important to work with a reputable roofing contractor who’ll provide accurate cost estimates, a quality installation, and ongoing maintenance services.

FAQs

Is a flat roof cheaper than a pitched roof?

Flat roofs are often cheaper than pitched roofs because they’re less complex to design, install and upgrade. However, they require ongoing maintenance due to their low rise, which makes them prone to water damage.

Many homeowners also enjoy using their flat roofs recreationally, meaning they suffer from more wear and tear and load-bearing issues in comparison to their less amenable alternatives.

What are the flat roof vs sloped roof cost differences?

A sloped roof (aka shed roof) and a flat roof are both characterised by their lack of a ‘pitch’ or ‘ridge.’ However, a flat roof has a rise of around 10 degrees while sloped roofs are usually angled between 25 – 45 degrees.

Sloped roofs are often cheaper than their flat roof cousins because they’re easier to install. Consequently, as a rough guide, the average cost of a sloped roof in the UK ranges from £120 to £275 per square metre, which includes the cost of materials and labour.

This means a typical 100 square metres sloped roof could cost between £12,000 and £27,500 overall.

However, the costs will be significantly higher for more complex installations or the use of premium materials, such as slate or clay tiles. The final price is also affected by factors such as the location of the property, access to the roof, and the time of year.