Home Improvement Ideas- Flat Roof Extensions

Not only are flat roof builds generally cheaper to construct than pitched roof extensions, the possibilities of what you can do with your roof to enhance the look and purpose of it are even greater.

By Larry Bohan on 21 May 2018

home extension lit up at night with bifold doors and roof lantern.

Despite being considered outdated by some thanks to a supposed susceptibility to water leaks, flat roof extensions are still the most popular form of home extension in the UK and for good reason.

Sceptics point to this apparent inability to effectively cope with the worst of the weather as reason enough to shun all flat roof extension designs. It is this belief, not flat roof extensions, that is outdated.  

Before we look at some examples of what is possible and show you a selection of inspirational flat roof extension products to get your DIY pulses racing, let’s once and for all put an end to the belief that flat roof extension means leaky roof.

The Flat Roof Theory

EPDM rubber roof system for flat roof

The belief that home extensions built with a flat roof are too vulnerable to water seeping into the home is about archaic and misinformed as another famous flat theory.

EPDM (Ethylene Propylene Diene Monomer) is leagues ahead of some older traditional flat roof materials, such a felt. Rubber roofing is one of the most durable and reliable roof coverings, with EPDM roofs able to last between 30 and 50 years thanks to a strong resistance to even the most extreme weather conditions.

A slightly more expensive flat roof system is GRP (Glass Reinforced Polyester). GRP is one of the most advanced roofing systems in the world and one of the most attractive too. Both GRP and EPDM roofing systems are available at Sterlingbuild for the best prices online guaranteed.

Flat Roof Extension Ideas

ECO+ Flat Glass Rooflights

eco+ flat glass rooflights in kitchen

An effective way of bringing an abundance of sunlight into the home is through installing one or a combination of flat glass rooflights. Flat glass rooflights are a cost effective way of brightening up a new extension with the potential to save you serious money on energy bills. 

Although pitched roof window market leaders VELUX and FAKRO are also heavily invested in the production of flat rooflights, if you are looking for a contemporary and stylish roof window that will not blow your budget, consider the options available from UK brand ECO+.

The incredibely energy efficient (1.1 W/m²K U-values) ECO+ produces flat glass rooflights in a number of sizes, including the ever popular 45x85cm rooflight that is now available at Sterlingbuild for its cheapest price to date while stocks last. The size of these rooflights makes them perfect to install in combination to ensure daylight reaches all corners of your flat roof extension.

Visit the ECO+ brand page to find out more and discover some of the industry's most innovate flat roof window designs.

Roof Lanterns

korniche roof lanterns

Roof lanterns are a great way of filling the home with an abundance of natural light. Once installed in a flat roof, glass lanterns can give your room the appearance of a higher ceiling, a seemingly small plus point, but one that can make the world of difference.

Once considered a bit of a risk given the ability of glass to make rooms too hot or cold, roof lanterns are no longer a gamble when it comes to insulation, evidenced by Korniche lanterns carrying U-values as low as 1.2 W/m²K to ensure your room’s temperature will stay comfortable all year round with tints available to reduce glare.

The thermal efficiency and attractiveness of roof lanterns is matched by the views they provide of the outdoors. The large, clear panes of glass allow you to watch the clouds go by during the day or gaze up at the stars at night. REAL Aluminium designs its roof lanterns in an extremely slimline design which means even less frame on show and even superior views.

Korniche roof lanterns can be purchased in a standard size or designed made to measure to any dimensions. Numerous colour, glazing and other spec options are available on our bespoke lantern service.

REAL Aluminium Bifold Doors

REAL aluminium bifold doors

Where roof lanterns and flat glass rooflights enhance the look and feel of a flat roof extension from above, bifold doors bring new spaces to life at ground level with ceiling to roof doors creating a seamless link between home and garden. 

Bifold doors and sliding doors are a perfect choice if your flat roof extension is part of an open-plan living space. Fitting a kitchen extension with glass doors to the outside allows you keep the kids or grandchildren in full view while cooking up a storm in the kitchen. This home improvement design seems to grow in popularity with every passing year and is rightly regarded as one of the most modern flat roof extension designs. Read a recent customer testimonal on REAL aluminium bifold doors here.

Bifold doors and sliding doors are all available from REAL Aluminium, made to measure if required. 

Bring Your Roof To Life

Grufekit green roof home extension

Your roof does not have to be limited to exclusive use as a shelter from the weather. Building a flat roof extension comes with a plethora of opportunities that would just not be possible with pitched roofs. The flat surface means you can turn your roof space into a valuable outdoor space, such as a balcony or roof garden, the latter of which is very affordable thanks to green roof kits from Grufekit.  

Roof gardens add value to your home as well as making it healthier, more colourful, more interesting and more environmentally friendly. According to an article in the Daily Telegraph, flat roof extensions with roof gardens can add anywhere between 10 and 15% to the value of a home, a smart investment to make should you ever decide to sell up. 

If you like the idea of growing a garden on your roof, access to the roof needs to be take into consideration. Mean of Access windows are available from Signature for you to easily climb up through so you can manage your new green space whenever you like.

For help designing your perfect outdoor balcony flooring, visit our sister website Roofinglines to explore a large range of promenade tiles.

Flat Roof Extension Cost

bi fold doors in living room extensions from REAL Aluminium

Another appeal of flat roof extensions lay in their cost. You will usually find flat roof extension cost is a lot less than that of pitched extensions.

Naturally, costs will vary depending on whereabouts in the country you are building and how large your roof is going to be. Outgoings will also be affected by whether you need to hire an architect and/or builder to assist you on the project or whether you or a reliable friend can tackle it.

Typically, flat roofs require less structural engineering and can be designed with more affordable material than pitched roofs. For a basic quality extension, you might be looking at a figure between £1,300 and £1,900 while for an excellent quality design, this sum could rise by £400 or so.