On most homes, the roof is the key external feature and with the wealth of options available when it comes to design, structure and coverings there are endless possible outcomes.

Whether you are building your own home from scratch, renovating an older home or extending, there are a number of criteria that will affect how satisfying your new roof will look.

Here are five important things that you should know about roofs.

1. Pitch Can Make or Break a Design

Arts & Crafts style home with steeply pitched roof

Characteristically, Arts and Crafts homes like this have steeply pitched roofs (normally between 48° and 51°)

As well as offering a satisfying aesthetic, there are practical reasons why you need to ensure that your project has the right pitch. Choose wrong and your project will look odd and leave you dissatisfied.

For example, if you are building a cottage-style home with a thatched roof, you’ll need a steep pitch of at least 45°(50°is better still). This pitch is not only a staple of cottage style, thus creating a visually satisfying structure, but will also allow rain to flow off the roof quickly and prevent ingress.

When it comes to gaining planning permission, designers can often be asked to reduce the pitch if it is deemed to have too much impact on any adjacent buildings, so be prepared to be flexible — your architect or designer will ensure that the end result is still visually satisfying.

Roof pitches diagram

A 39° pitch is good for a Georgian-style home,
while a steeper pitch is perfect for an Arts and Crafts house

2. You Can Factor Insulation into the Design

Effective insulation is key to the efficiency of our homes (and lower heating bills). If you are not planning on using the loft space in an existing home, then you can simply roll out insulation above the loft floor. But if you are planning on converting the loft into living space, then you’ll need to insulate directly under the sloping roof.

If you’re building a new home, a cost-effective and simple solution is to construct a warm roof, where the insulation sits directly above the rafters with a roofing membrane laid over the top.

If your new roof has a simple design, then you could also consider using insulated panels laid across a series of beams instead of rafters.

3. Want to Convert the Loft? Plan Ahead

Choose the wrong structure and it could prove more complex and costly to convert the roof area into useful living space down the line. 

In prefabricated trussed roof structures, a fink truss (where the roof members form a ‘W’ shape) roof will be harder to turn into usable space compared to an attic truss roof, so it’s worth deciding early on if you want to be able to use the space down the line. A more expensive roofing structure now, could mean cheaper conversion later.

4. There’s a Plethora of Structural Choices

Green roof on charming hillside home

Green roofs, like on this eco-friendly self build, are a great option for those wanting to offset their carbon footprint as the plants absorb CO2

While some methods are quicker and easier (and less expensive) than others, there are more ways than ever to build a roof structure. At the typically less expensive end of the scale, you have your prefabricated trussed roof options, with fink trusses often offering the cheapest solution, while at the more expensive end, you have your cut roof and panellised options such as SIPs.

Curved or panellised roofs work best with simple shapes and it’s worth remembering that the more complex the design, the longer it will take on site and the higher the end cost will be.

5. Flat Roofs Aren’t Actually Flat

flat roof on low profile home on stunning plot

The flat, low lying roof on this self build in Skye helps the home blend into the landscape

Flat roofs are a popular choice for those wanting to build contemporary-style homes (or embrace the Modernist aesthetic). But despite the moniker, they aren’t actually flat. In order to prevent rainwater pooling and causing damage, flat roofs are built at a low pitch, known as a fall, to facilitate effective drainage. 

The fall should be around 1:40 (never less than 1:80) in order to work effectively.

Check out how Charlie Luxton prepared the flat roof structure on his self build project.

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