The roof can make or break how a house looks, and what it’s like to live in. Architect Julian Owen shares his insider secrets to help you get the best design for your project

T he roof is a fantastically versatile design element of a house. It can be used to create complex and interesting shapes that add character and wow factor, so it’s a crying shame it sometimes seems to be plonked onto a new home almost as an afterthought.

Any house designer worth their salt should be able to visualise a project in three dimensions as the layout develops (a skill that’s particularly important when pitched roofs are involved). So there’s no need to refine the floorplan first and work out how to cover it later - this should all be part of the same coherent process.

The first decision you and your designer will need to make is whether to go flat, pitched or a combination of the two. This choice will help to define the style of the building. So here I’m looking how to choose between them, how to maximise the architectural opportunities with this aspect of your project and what materials might work best.

Flat roofs

The term flat roof technically refers to any roof that has an angle of less than 10°. This style can give either a flavour of cool modernism or a whiffof naff1970s vibe, depending on your point of view and how well they integrate into the design. Generally speaking, a flat top to a house that has traditional brick detailing will look unfinished. It will fit perfectly, however, over a building that is unashamedly contemporary in style and materials.

Although they’re seen as a 20th century innovation in the UK, flat roofs are an ancient tradition - particularly in hot, dry climates where problems with damp and leaks are rare. Lead versions have been happily incorporated into large public buildings for hundreds of years. The much cheaper standard flat roof construction used on domestic houses, however, once had a reputation as a maintenance liability. The culprit was old fashioned roofing felt, which moves as the outdoor temperature fluctuates, especially in summer, and so quickly develops cracks which in turn leak.