How Long Does It Take To Install A Flat Roof?

Daniel Bracewell • 10 August 2024

It has become increasingly common for homeowners, building managers and architects to opt for a flat roof rather than a conventional sloping roof, because the results look fantastic, the prices are reasonable and the spaces can be versatile if the roof is installed properly by specialists.

Whether the aim is to design a modernist house, install solar panels, fit a green roof or simply have an outdoor upstairs space, a flat roof is a highly desired option, but eager homeowners often ask how long it can take to install one.

This is a question that gets asked a lot but is ultimately quite difficult to truly answer, as it can depend on a wide range of different factors.

An average-sized house roof will typically take at least a week, whilst the flat roofs of large commercial buildings can take at least three months.

These assume rather ideal scenarios, and that is not always possible when it comes to installing flat roofs, particularly given that a major factor that governs timescales is out of any of our control.

The size, shape and complexity of the roof are the biggest factors and ones that a specialist will typically use to give a baseline rough estimate. Small bungalow or garage flat roofs will typically take at least three days, the average is a week, larger roofs can take over 6 weeks and commercial roofs considerably longer than this.

These timescales are widely affected by the nature of the roof itself. If it is a tall building which needs a flat roof installed, this will necessarily make the project take longer to ensure that it is done safely and in keeping with health and safety legislation. This is also true if there is any confined space work involved.

There are multiple waterproofing and sealing materials that can be used, but the simpler it is to install, the faster it will be to apply and the less time a flat roof will take to finish.

Finally, the weather is a huge factor, as strong winds can make it unsafe to work at height, and heavy rain showers can affect the use of adhesives, the waterproofing of the building and can bring roofing work to a grinding halt.

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Can You Install Solar Panels On A Flat Roof?

by Daniel Bracewell • 10 December 2025

If you’re exploring how to lower your energy bills and reduce your carbon footprint, you may be looking at the likes of solar panels for your home. But what if your property has a flat roof rather than a pitched roof? Can you still install solar panels on a flat roof? The short answer is yes, you can! In fact, it is often easier to install solar panels on a flat roof than it is to fit them to a sloped roof, which might make this an even more appealing avenue to explore when you’re looking at flat roof ideas . In many cases, you also don’t need planning permission to install solar panels on your flat roof. Of course, there are exceptions if you have a listed building or live in a conservation area, but if you own your house (different rules apply for flats too), you should be free to add solar panels to your home as you choose. There are different kinds of mounting systems for flat roof solar panels and which is most appropriate for your home will depend on the direction it faces. It is worth noting that the cost of installing solar panels is often higher on flat roofs because of the mounting system, but some of this can be offset by the lower labour costs because the installation process is usually more straightforward. One of the main reasons homeowners install solar panels is to reduce their energy bills. Many report savings of hundreds of pounds each year, which means these panels often pay for themselves relatively quickly. What’s more, under the Smart Export Guarantee , you can sell any energy you don’t use back to the National Grid, which can increase the rate at which your investment in solar panels pays for itself. So, if you are exploring ways to make the most of your flat roof, consider solar panels as an option to reduce your energy bills and do good for the environment.