Building a new roof requires a high level of skill and expertise and should be left to a professional builder. However, there is no reason why minor repairs should not be attempted, therefore knowledge of roof construction and the components will be useful.
Basically there are five main components in roofing:
Most houses have a pitched roof structure with a timber framework. The four main types of roof structure are Gabled, Hipped, Mono-pitched and Mansard.
A gabled roof has two pitched planes that slope around triangular extensions of the end walls. The triangular extension is the gable.
A simple hipped roof will have four sloping planes. The hip is the joint between two adjacent slopes. Some roofs are extremely complex with numerous hips.
A mono-pitched roof has only one slope and is commonly found on extensions.
A mansard roof comprises of two planes sloping at different angles on each side of the building. Mansard roofs create a spacious living area in the roof space.
Truss clips are used to connect the ends of roof joists to the wall plate which is the timber beam that runs across the top of the wall.
Roofing felt is laid beneath the tiles to create a waterproof barrier. It can be laid directly over the rafters in horizontal strips with the edges of each strip overlapping. Alternatively, timber sheathing can be fixed to the rafters and then the roof felt laid over the ply.
Timber sheathing is usually sheets of plywood. It is laid across the rafters, staggering the joints as you move up towards the ridge. To fix the sheathing in position nail the sheets of plywood to the rafters using a fixing every 150mm (6in). To improve ventilation in the roof space gaps are sometimes left between the sheathing, as you get closer to the ridge. Sheathing is generally used when the roof has only a slight pitch, but in some areas the Building Regulations make it a requirement. If you are making a repair to the roof felt always match the new material to the existing felt.
A very durable roofing felt with excellent waterproof properties commonly used for covering flat roofs.
Roof tiles need a fixing point and this is provided by fixing timber battens horizontally across the pitch of the roof. They are fixed in position by nailing them to the rafters. Timber battens must be evenly spaced. The space between the battens (also known as the gauge) will be determined by several factors:
The roof of your property will almost certainly be covered with roof tiles of one sort or another. The only situation where this will not be the case is if you have a thatched roof. As thatching is a highly skilled craft taking years to learn, it is highly advisable to engage the services of a professional thatcher.
Roof tiles are available in a variety of styles and materials, and the type of tile you use will depend on the pitch of the proof and the prevailing weather conditions. When fixing tiles it may be sufficient to hook the protruding nibs over the timber battens, but if the property is located in an area of strong winds you may want to consider nailing some or even all the tiles in place. The most common types of roof tiles are described below.
Lighter than clay tiles, slate tiles are strong and durable thus providing a longer life span than most roof coverings. However, they can be quite expensive. Slate is a natural and dense material that is split into thin sheets and cut into small units used on pitched roofs. There is also an option of having synthetic slate tiles, which are stronger, look similar but are less expensive.
Each slate tile is fixed by nail to the roof. A shallow roof pitch and high winds will make slates susceptible to vibration, which can loosen the tiles and even cause breakage.
Often used as flashing for valleys and abutments, GRP is being used more widely as an alternative to lead flashing.
Basically this is a tile with a vent incorporated in its design. Generally used in situations where a solid wall separates the roof space. Fitting tile or slate vents at the bottom and top of each side of the roof will ventilate the roof space either side of the wall.
Excellent material for covering sheds and flat roofs, the reinforced butyl rubber will not contract over time. It is also frost and rot proof. Self-adhesive products are available
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