FRAME MATERIALS

■ ALUMINIUM

Popular for modern homes, aluminium frames can be supplied in virtually any colour. They’re also lightweight, strong and maintenance-free.

■ COMPOSITE Made from a mixture of materials, composite doors are often more expensive. Those made from timber tend to be clad in a weatherproof material for a tough, low-maintenance exterior.

■ TIMBER These offer good thermal properties and a classic look. However, they’re also vulnerable to the weather, need treating and maintaining, and can be prone to warping.

■ STEEL Used in buildings since the 1930s, Crittall brand steel frames are back in fashion. They combine a slender look with the benefits of thermal performance, security, durability and easy maintenance.

■ UPVC Good value and weather-resistant, UPVC doors don’t need painting and are easy to maintain, and a popular choice. But it’s nigh-on impossible to alter the size of them once they’re ordered and fitted.