Patio Doors or Bifold Doors?
When choosing whether to have a sliding patio door or a bi-fold door, there are a number of pros and cons that you may want to consider:
Bi-fold doors have an obvious advantage that they can open up about 90% of the aperture, letting in lots of fresh air and really opening up the room to the garden. Patio doors by comparison will typically open up between 50% and 65% of the aperture.
If you want to open the door for a little ventilation, the patio door offers the most flexible solutions with the ability to open the door just as far as necessary to make the room comfortable. The bi-fold door’s flexibility
will depend on its design, but often opening a door leaf is the minimum you can do to let some fresh air in.
If having an uninterrupted view is important, then a patio door may be a better option. The bigger door leafs with large panes of glass give more of a panoramic view than a bi-fold door that comprises several narrower door leafs, each with a frame around them.
Most people choose to have their bi-fold doors open out rather than open in. The main reason for this is that if you open the doors when it has been raining, you don’t want the rain water to drip inside the house.
With the bi-fold door, you can choose to have all the door leafs stacking to the left or the right, or you can choose to split them so some stack each side. You can also choose whether the doors open in or out. When making these decisions, it is worth remembering that the doors require some clear space around them in order to open, and you don’t want to be moving furniture or plant pots every time you open the doors.
There are a number of bi-fold door designs to choose between. The number of door leafs will to a large extent be dictated by the size of the opening, but it is worth considering the benefits of choosing a design with a traffic door. Typically found on designs with an odd number of door leafs, the traffic door is a single door leaf that can be opened without unlocking the rest of the door leafs. Effectively operating just like a normal back door, this is convenient for when you just want to nip out into the garden quickly.
Bi-fold doors are usually mounted on sets of rollers that run in a track set into the floor. The weight of the door is carried by these rollers and all is well. There are a few bi-fold doors where the door leafs are hung from rollers that run in a track across the top of the
door. This can work well in isolation, but it is worth considering that as the top of the door frame is secured to the lintel above the door, the extra weight of the door suspended from the frame will be transferred to the lintel. If the lintel is not strong enough to carry this extra weight, there is the potential for some quite catastrophic consequences.
Look at the marketing photos of bi-fold doors and you will usually be presented with a door that has a flush threshold, meaning there is a continuous floor with no step between inside and outside. This can certainly be achieved, but it is worth considering that most bi-fold doors come with a choice of as many as four different threshold options. The reason for this is that
there is a trade off between the height of the threshold and the level of weather resistance the door can offer. The flush threshold will not be very good at keeping out the draughts and the doors with the best weather ratings will have a higher threshold to step over. It is certainly worth considering how exposed the door will
be to the elements, but rest assured that most people find there is a satisfactory compromise using one of the intermediate thresholds.
Whether you are considering bi-fold doors or patio doors, keeping the tracks clear of debris will be important to the long term reliability of the doors. It is usually just a question of running a vacuum cleaner over the track when vacuuming the rest of the room. However, some sliding doors have a design where rather than having the wheels attached to the door leaf, the doors run on wheels that are set into the
track at intervals.
Most of the track is covered by a cap that has slots for the wheels to poke through. This solution is considered by some to be fundamentally flawed as the track is hard to clean and a build up of dirt in the track may eventually stop the wheels from turning. It is also possible that in winter, any water that has not drained properly from the track may freeze and stop the wheels from turning altogether.
Patio doors are designed to achieve a compromise between being easy to open and close (which requires little contact between the moving door leaf and the outer frame) and being good at keeping out the wind and the rain (which requires a good seal between the moving door leaf and the outer frame).
The majority of patio doors are opened by pushing the door leaf to the side. When doors are of moderate size and weight this ‘slide’ mechanism allows the doors to be opened easily enough.
For the bigger doors (it is possible to have door leafs that are up to 3m high and weigh up to 400kg) it is advisable to opt for a liftand-slide mechanism. Turn the (slightly longer) handle through 180° and the door leaf is lifted by a few millimetres to reduce the friction
between door and frame. This makes it possible to move even the biggest and heaviest doors with relative ease.