Bi-fold, sliding or French: Which doors should you choose for your extension?

Oct 3, 2023 | Property News

If you are thinking of adding a rear, side, or wraparound extension to your London home, then one of the most important details is going to be your choice of doors to your back garden. Far more than a simple entryway, bi-fold doors, sliding doors, and French doors can all create that “wow” factor when you show off your new and improved property to friends, family, and potential future buyers. So, what are the options?

French doors

French doors are the more traditional option, and can bring a classic sense of charm and style to any home. For older period properties, such as the Victorian houses that make up much of London’s housing stock, French doors will be in keeping with their traditional style. Or for more modern houses, French doors can add some character.

Importantly, for Londoners looking to introduce more natural light to their home but maintain a little more privacy than the huge panes of glass found in modern sliding and bi-fold doors, then French doors would make a great choice. Or for those that want the style of French doors, but are looking for more natural light and openings to the outside on a hot day, then adding multiple French doors across the back wall can work beautifully.

Sliding doors

Sliding doors have been popular since the 1960s, and continue to be popular today thanks to their simplicity and the extensive panes of glass which offer stunning views into the back garden and can bring sunlight flooding into your home. They are also the most space efficient option for back doors as they do not open into the property like French doors or need room to fold like bi-fold doors, and so are beloved by homeowners with a little less space to play with at the back of their property.

Bi-fold doors

Bi-fold doors have seen a surge in popularity across London in recent years with homeowners looking to create a focal point on their new extensions, and they can certainly bring a “wow” factor to any home.

They offer the same stunning views and floods of natural sunlight as sliding doors, but because they offer a way for homeowners to peel back an entire wall, they can really bring a sense of the outside-in on a hot summer day. And for Londoners looking to really make an impression, they can be added in conjunction with floating corners, which means that it is not just the back wall that can be folded away, but the side walls as well for a full glorious 180 degree view.

It is easy to understand the allure of bi-fold doors, but with their beauty comes an expensive price tag. They also take up a significant amount of space when folded, so work best in properties with larger outdoor space and for homeowners with larger budgets.

Aluminium vs Crittall steel vs timber vs uPVC

Garden and patio doors can be made from aluminium, timber, or uPVC and each have their own qualities. The best option for you will be determined by the style of door you are looking to add, the aesthetic you are trying to achieve, and critically, your budget.

In general uPVC tends to be the cheapest option, requires minimal maintenance and is easy to clean, but it does not offer the traditional beauty of timber or the strength of aluminium. The material can also deteriorate over time faster than other options.

Timber is the traditional material for French doors, and so for those looking to create that timeless look, or those with a listed period property that need to maintain its aesthetic, it is an ideal choice. Sliding and bi-fold doors can also be made with timber frames, and whilst these can look great they will be thicker than frames made from aluminium, and so do not quite offer the same views. It is also worth noting that wood requires more maintenance than the other choices, however it is also the easiest to repair if issues do arise.

Steel-framed windows have been popular for over a hundred years, with hot-rolled steel stronger and more durable than timber and requiring less maintenance. Modern Crittall windows and doors will also not rust as they are generally coated in a polyster powder after a hot dip, which protects them against rust for over 20 years. Crittall Windows were the original pioneers in the industry and remain the market-leaders, and so classically designed steel window and door frames will often be described as having a “Crittall look”, even if they are not manufactured by the brand themselves.

Aluminium is strong, lightweight, low maintenance, and offers excellent thermal insulation. Due to its strength, aluminium frames can be thinner than other materials and so are perfect for those looking to create the most uninterrupted view of the outside with sliding or bi-fold doors. However, these properties come with a hefty price tag.


If you are considering building a new extension, then Good London Builders have the expertise to make your dreams a reality. From a rear extension on a Victorian property with beautiful traditional wooden French doors to a major double-story wraparound extension with bi-fold doors offering a full 180 degree view of the garden, we can help guide you through the process from start to finish. Call Good London Builders today on 0207 978 5097.

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