Bi-folding doors appear to be the latest phenomenon in exterior door sets and rather than having one of the traditional, sliding patio door variety, a lot of homeowners are turning to this type instead. The main reason for this is because the extra space that they bring to a room and the fact that one can open a whole wall up to the garden means that a conservatory, or any other room stretching onto the garden for that matter, can appear that little bit bigger. This of course makes them an excellent solution for the prospective seller, although they are certainly not only acquired for their house-selling potential.

However, it would be fair to say that there are slightly more considerations with this type of door than any other. Most of the time, one simply has to choose the type of material for a standard patio door, but when you breach into the bi-fold category there are slightly more questions to pose. We’ll now take a look at some of the issues you should consider when contemplating that next bi-fold door purchase.

Only buy doors from companies who will provide the relevant certificates

While they might appear to be quite a small element of your house, bi-folding doors still need to comply with the building regulations. Even though you are highly unlikely to witness a building control officer visit your property during the installation of the doors, you will need documentation to certify that they do meet with the regulations. This will become particularly important if you decide to sell the property and if you don’t have any paperwork, your bargaining power might be compromised. Companies such as will always provide such documentation and thus protect your future in the event of a sale or visit from the local authority.

Don’t consider any door with an external track

A bit reason why patio doors have developed so much over the years is because of security and one of the most common illegal methods of entry into a home was removing the door by lifting it off its runners. This was mainly made possible by external tracks and if you are approached by a company who sells doors with such a track, you should run a mile. The same security issues will still be prevalent and while they may claim that “anti-lift” devices have been implemented, nothing will beat the internal track which makes the above lifting technique impossible.

Consider the weather-tightness of each door you look at

This is partly related to the building regulations again, with weather tightness and energy efficiency one of the most common features of Part L. Every bi-fold company will have their own spiel about how their product will prevail against any type of weather, but the only way you can tell is by looking at the specification. For example, some companies promise a low threshold, but this makes achieving weather tightness very difficult indeed and you should question just how the product will prevent the wind from entering at this low level.

Always look for the insurance-backed guarantee

You’ll probably be firmly aware that the double glazing industry is one of the most fickle out there and the nature of bi-fold companies mean that they are in a very similar position. Many come and go, and this means that guarantees are regularly thrown out of the window. Consider the number of things that can go wrong in these products, whether it’s damaged glazing, a broken folding mechanism or anything else; always make sure the guarantee is backed by an insurance policy meaning that you will be paid out no matter what.