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Choosing which Bi-fold doors to install in your home can be a challenge; once you’ve decided on the space and size, you then have to choose the right material in terms of longevity, thermal efficiency and aesthetics, so how do you choose?

To help make your decision a little easier, we’ve put together a guide to the benefits and downsides of each material available for folding doors. We’ll look at the following aspects of timber, UPVC and aluminium Bi-fold doors:

  • Strength
  • Thermal efficiency
  • Maintenance
  • Style
  • Price


Bi-folding door frames have to be strong enough to support huge expanses of glass whilst also being robust enough to stand up to the elements.


  • Strongest material available
  • Stronger material means smaller frames, more glass and better views
  • Strong enough to be used for corner or bay window doors
  • Light weight and easy to manoeuvre

Aluminium is the strongest material used to manufacture Bi-fold doors. It can support more glass with less material than other types of doors which means you can benefit from larger expanses of glass and smaller frames (and therefore a better view and more light) than when compared to timber or UPVC. The strength of aluminium as a material for door frames ensures the doors remain resistant to flex, twist, expansion and contraction with heat variation, which is particularly important at coastal locations or where doors experience direct sunlight for long periods.

A further benefit of the metal’s strength is that it can be used to manufacture Bi-folding doors for corner posts or for bay windows, which timber and UPVC simply wouldn’t be strong enough to do.


The strength of timber doors can vary dramatically as each door is engineered, which means it is made up of a number of different pieces of wood which are glued together with polyurethane. Engineered timber is much stronger than solid timber doors as the layers of wood combined with polyurethane build up strength in the door. Despite this, even engineered timber can be prone to warping if the frames absorb too much moisture or are exposed to strong sunlight for a long time. Once the material has warped, it can mean the gaskets can’t be sealed properly, which means there could be gaps between each doors, leading to further weakness and issues with thermal efficiency.


UPVC doors offer a similar strength to timber and, as with timber doors, UPVC can warp when exposed to extreme weather conditions. When large UPVC frames are used, such as with folding doors, heat variations can cause the material to expand and contract, which can make the doors difficult to open, fold and close.

Thermal efficiency

Although the type of glass installed in Bi-folding doors has a huge impact on how thermally efficient they are, the frames also play their part.


  • Thermal break in frames to prevent conductive properties of metal drawing heat out of the room
  • Thermal glass available

Regardless of what material they’re made of, all Bi-folding doors must have a U Value rating of at least 1.8W/(m2K) when replacing existing doors and 2.0W/(m2K) for new builds or extensions. This should be for the overall U Value, rather than the centre pane U-value often quoted by Bi-fold door suppliers. The U Value refers to the amount of heat lost through the glass and framework of the doors, Origin’s aluminium doors have a U Value of 1.3W/(m2k). As these doors literally become ‘glass walls’ it’s vital that they are as thermal efficient as possible.

Traditionally, aluminium frames have been associated with poor thermal efficiency as the metal is a natural conductor rather than an insulator. However, many aluminium Bi-folds (including Origin’s) feature a polyamide thermal break. This break separates the aluminium frame into interior and exterior pieces, joining the frame together with a less conductive material which resists thermal transfer from the outside face of the doors through the living area inside. This break acts as a thermal barrier, reducing the flow of thermal energy through the aluminium.

As well as being environmentally friendly in terms of thermal efficiency, aluminium is also highly recyclable and all of Origin’s doors are made from 100% recycled aluminium, making them an ideal choice for the environmentally conscious.


A typical U Value for timber folding doors is 1.4W/(m2k) but in cold weather, timber doors are prone to contracting, which can cause minute gaps in between seals which can allow drafts to creep into the home, making it feel cooler.


Of all the materials, UPVC generally has the lowest level of thermal efficiency, coming in just slightly behind timber with a typical U Value of 1.7W/(m2k).


To ensure Bi-folding doors are robust against the elements, they should be weather rated against British Standards.


  • Only need cleaning once a year in a normal environment
  • Available with a marine grade finish to prevent rusting in coastal climates
  • Can also be finished to withstand chlorine in swimming pool environments

Aluminium frames require the least maintenance by far when compared to timber and UPVC. To be kept in top condition, aluminium doors only require cleaning with warm soapy water once a year as a minimum. As the frames are powered coated, they require no repainting and will maintain their colour indefinitely. Doors powder coated in aluminium will not corrode, discolour, rot or warp and are so resistant to fading in sunlight that the doors can be installed in extreme hot climates with no problem.


Timber doors are the most demanding when it comes to maintenance as they can look weathered over time, especially if they are south facing and therefore in the sunshine for longer. The timber will need repainting every few years to maintain its beauty and to ensure the doors are fully sealed to prevent moisture from seeping into the wood.


UPVC doors are relatively low maintenance too but UPVC does tend to look worn more quickly than aluminium, which maintains its aesthetics and timber, which can be repainted if it starts to look tired.


For many people, the deciding factor of which Bi-fold doors to purchase comes down to how they look and the material the doors are made from is a key decision when it comes to style.


  • Strength of aluminium means smaller frames and a larger expanse of glass
  • Powder coated RAL colours available
  • Different colours on inside and outside frames available

Aluminium frames provide the perfect surface for powder coating; a solvent free powder which is applied to the metal at high temperature to provide an even, highly durable finish. As well as standard finishes, such as metallic and wood grain shades, Origin also provide over 150 RAL colour finishes, ranging from bright reds, blues and greens to more subtle pastel and muted shades. Different powder coated finishes can be applied to each side of the frame, to match the interior and exterior style of your home.

Another key advantage of aluminium when it comes to style is that no other material offers the sleek finish of aluminium Bi-fold doors as the frames are exceptionally narrow, without compromising strength, guaranteeing you the best view of your garden.


For many people, timber is the ultimate aesthetic choice for windows and doors, particularly in period properties as timber is naturally very beautiful and can be finished with a choice of stains or colours. Timber doors can also feel ‘warmer’ when compared to aluminium and UPVC and rank very closely with aluminium frames for thermal efficiency.

Although timber can be treated with different finishes, it can’t be given a powder coated coloured finish. Timber does show signs of wear and tear more readily and requires regular maintenance. However, the exterior of the doors can be clad in aluminium to make them sturdier, which would be recommended in coastal or sunny climates. Cladding timber doors in aluminium can be expensive though, so an alternative could be to opt for aluminium doors with a wood grain finish.


There’s no getting away from the fact that UPVC doors do not stack up well against timber and aluminium when it comes to style. The main downside of UPVC aesthetically is that it can look cheap and is particularly unflattering to period properties. One of the typical features of UPVC doors used as front or back doors is the chunky frame which can make the doorway look narrow. This is also the same with Bi-fold doors as the frames need to be wider than aluminium so there is enough plastic to support the glass, as a result the frames can look bulky and even detract from the view. Some larger companies do offer a range of coloured finished for UPVC doors but on the whole, white, grey, black and wood grain are the most commonly available colours.



  • Most expensive option but can last well over 30 years

For many people, the main drawback of aluminium doors can be the price as, compared to timber and UPVC, these doors are much more expensive. However, a 4 Bi-fold door set can cost around £3,000 (excluding fitting and delivery, which would apply to all doors, regardless of the material) so they are more affordable than you may think. Origin’s aluminium doors are handmade and this is reflected in the price as the doors go through a rigorous checking process.


Engineered timber doors do tend to be less expensive than sold timber doors, although solid doors are more vulnerable to wear and tear and require more maintenance so could work out more expensive in the long run. For a set of 4 solid oak Bi-fold doors you can expect to pay around £3,000, whereas engineered timber doors cost around £2,000 for a set of four. A set of composite doors (where the timber is clad in aluminium) will cost around £5,000, so are by far the most expensive option.


The main selling point of UPVC Bi-fold doors is the price as they tend to be much cheaper than timber or aluminium and you can expect to pay around £1,500 for a set of 4 doors with a 10 year guarantee. The reason why UPVC doors are cheaper is because they are mass produced.

Overall, aluminium is highly recommended when considering materials for Bi-folding doors. The material is light weight, strong and available in a huge range of powder coated colours to achieve the perfect match for any property, regardless of age or style.

Looking for more information?

For more information on material choices for Bi-fold doors please check out the following articles and websites:

Real Homes Magazine

General advice on choosing bi-folds from expert home renovator Michael Holmes:

Folding Sliding Doors: Your Questions Answered

Double Glazing Blogger

We share our pros and cons of Bi-fold door materials with the readers of Double Glazing Blogger:

Bi-folding Doors – Which Material is Right for Your Project?


Aluminium Trade Supply

This website is dedicated to sharing information on the benefits of aluminium for windows and doors and has a wealth of information on aluminium:

Aluminium Trade Supply

If you have any questions related to Origin’s doors then please get in touch.

Origin is an award-winning British manufacturer of high quality, bespoke aluminium folding sliding doors and made-to-measure electric roller blinds, individually tailored to any bi-folding door installation.

Every bespoke bi-fold door is designed and manufactured at Origin’s impressive state-of-the-art UK factory in High Wycombe, and each door set comes with a 20 year guarantee, so you can be sure your design will continue to look good well into the future.

Origin realises that not all extensions run according to plan. With this in mind, they have developed a unique service it calls ‘Your lead time, not ours’ available on its most popular colours, which means homeowners can time the installation of their bi-fold doors around their build schedule.