Types of Roof Structures

Before you start any roof project, it's essential to grasp the fundamental parts of your roof's construction.

Pitched Roofs

If your home features a pitched roof, it usually has a sloped design covered with materials like tiles or slates, creating a hollow area known as the loft. This type of roof relies on various wooden components. These timbers collaborate to bridge the space across your building, hold up the roof covering, and channel the weight from elements like wind and snow down into your walls.

• Rafters: Your roof's primary slope comes from the rafters. These wooden beams run from the top to the bottom of the roof, providing the main support for your tiles and the battens they sit on.

• Ridge Board: At the very top, where the opposing rafter pairs meet, you'll find the ridge board. This timber forms the highest point, or apex, of the roof structure.

• Purlins: Purlins are long, horizontal wooden beams that you'll often see running roughly halfway along the length of your rafters. Their job is to act as extra support, effectively shortening the unsupported distance (or 'span') of the rafters and making the roof stronger.

• Struts: To provide additional stability for the purlins, struts are used. These are diagonal wooden pieces positioned at an angle, either bracing against a wall that supports weight or connecting to another timber that itself rests across the ceiling joists below.

• Ties: Ties are horizontal timbers crucial for stopping your roof from pushing outwards and spreading apart. They often create an 'A' shape within the roof structure. These can be the same timbers as your ceiling joists, or they might be separate horizontal pieces installed partway up the roof, usually above where the purlins sit. This setup is particularly common in terraced properties.

• Ceiling Joists: While their main role is to support the ceiling of the room below, ceiling joists can also double up as roof ties. However, be aware that their dimensions typically aren't sufficient to bear the weight of a standard room. If you're planning a loft conversion, you will likely need to reinforce them.

Flat Roofs

In contrast to pitched roofs, flat roofs feature a more straightforward construction. Essentially, they involve a series of joists stretching horizontally from one wall to another. These joists are then topped with panels, which receive a protective layer such as felting or another type of waterproof covering. Importantly, flat roofs aren't perfectly flat; they incorporate a gentle slope to ensure rainwater can drain away effectively.