Folding sliding doors featuring large glazed surfaces but framed in variety of materials – uPVC, aluminium, hardwood or softwood, for example – can be an attractive alternative to traditional patio doors, French doors or windows. Bi-fold sliding doors are available in a number of styles – hung from the top or the bottom – with multiple panels, opening or folding to the left or to the right, or even around corners, to maximise the available space in your home.
Folding Sliding Bi-Fold Door Materials & Construction
Folding sliding doors can open wider than traditional patio doors and French windows and even conventional sliding doors. Nowadays their construction is such that they are highly resistant to penetration by water and air, and sealed bearing units, toughened wheels, etc. mean that even the heaviest sliding doors can be operated effortlessly, and safely.
uPVC is one choice of material for folding sliding doors and although – in theory at least – it is virtually maintenance free, it does lack the structural strength of some other materials and is more prone to expansion and contraction in response to changes in temperature. Many uPVC bi-fold doors have elements of aluminium, or steel, incorporated into their construction. Aluminium, itself, is strong, yet lightweight, and can be fashioned into slim folding sliding doors, with a contemporary look and feel but which can nevertheless be stacked into a small area. Hardwood, or softwood, folding sliding doors look and feel warmer but require regular maintenance – staining, etc. – so a popular option is to combine the durability and weather resistance of aluminium on the outside, with the warmth of timber on the inside. Whichever material you opt for, ultimately remember that a folding sliding door should not be something that you look to replace very often – if indeed at all – so look for a manufacturer that offers a guarantee of at least 10 years on its products.
Depending on the exact nature of the door(s) that you choose many manufacturers can pre-finish – stain, paint, etc. – folding sliding doors in the colour of your choice to suit the remainder of your home. Door furniture, or ironmongery, is also available in a range of styles, colour and finishes.
Folding sliding doors obviously present heat loss issues and Part L Building Regulations state that a U-Value – the amount of thermal energy transported through the door(s) per unit area, at a temperature difference of 1 Kelvin (or 1°C) – of 2.2W/m2K must be achieved for all new structural or renovation work. Glass by definition is not particularly energy efficient but it may be possible to offset a higher U-value by incorporating double glazed windows elsewhere in your home or including a thermal break – a material that conducts heat only poorly – between the exterior and interior of folding sliding doors. Most folding sliding doors are supplied with glazing already in place but many feature “Low-E”, or “Low Emissivity” glass – glass coated with a thin layer of metal or metal oxide – which can reduce the loss of thermal energy by anything up to 50%.