Bifold doors now form part of almost all new build home extensions due to their ability to open up large unobstructed openings allowing the new living space to seamlessly merge with the garden.
The intensive growth in demand for these folding sliding doors in the UK in recent years has led to a substantial increase in the number and type of different door systems now available to the consumer. They are now widely available in a choice of materials and finishes with the three most popular being thermally broken aluminum, upvc and hardwood.
Choosing the right bifold door for your project is an important decision and one that should not be taken purely based on cost alone. Your budget will naturally have an influence on your buying decision but there are other important factors that need serious consideration to ensure you are not disappointed with your purchase. Here are the top five points that are considered by many as the most essential research when considering a bifold door purchase:
1. THERMAL PERFORMANCE
Since most bifold door installations will be subject to compliance with building regulations it is important to check that the folding door you are about to buy will meet your local authority's interpretation of current building regulations in terms of overall U-value performance. This calculation is based on the specification of the double glazing together with the profile design and dimensions to determine the insulation benefits of the door measured in U-values with the lower the value the better the insulation achieved. The minimum acceptable under current building regulations for replacement doors is a 1.8 U-value but some local authorities will insist on lower values specifically for new build extensions.
2. GLASS SIGHT LINES
Another important consideration should be the sight line or width of door profiles between each panel of the folding sliding door as this will affect the visible glass area available when the door is in the closed position. Most bifold doors are designed with dedicated profiles to minimize these sightlines as much as possible but some timber and many upvc folding doors use wide, chunky profiles that produce very broad sight lines in excess of 200mm wide that will extremely spoil your view.
Most folding doors will feature a high security locking system but many still use face fixed or flag hinges that can pose a possible security issue and allow the hinges to be removed from the outside when the door is closed. Some upvc bifold doors may also use an exposed gear system that is accessible from the outside of the door when the door is closed which can also pose a possible security threat. You can eliminate these potential security problems by ensuring you choose a folding door that has fully understood driving and hinge fixings.
Although a flush threshold is the most popular option specifically for internal bifold doors this may not always be practical in some cases and a conventional raised threshold will need to be used. It is important to note that the height of these can vary somewhat with some upvc bifold door thresholds exceeding 125mm. Such a high 'step-over' threshold may create an accessibility issue for children and the older generation. The latest bifold door designs offer raised thresholds designed to minimize the trip hazard with some offering thresholds as low as 50mm high.
5. TOP HUNG OR BOTTOM ROLLING
Some bifold doors are hung from the top to allow for a minimal threshold at floor level but with all the weight of the door being supported from the top a substantial upgrade of the lintel is normally required for strength and stability. Bottom rolling folding doors are a cost effective and popular alternative since the weight of the door is transported at ground level rather than suspended from the lintel.
Whether you decide on an aluminum, upvc or hardwood bifold door it is a major purchase for your project and one that should be carefully considered to ensure the very best value for your money. Buying a cheap bifold door may prove a disappointment unless you check carefully that the door you are buying will meet your needs and expectations before you order.