Understanding different types of pitched roofing designs
Pitched roofs cover a huge range of properties, from domestic to commercial and historic. In this article, the different types of pitched roofs are presented.
WHAT IS A PITCHED ROOF?
Pitched roofs slope downwards, normally in two sections away from a central beam that slopes downwards. This is typically in two parts, at an angle away from a central ridge, but sometimes in one part, from one edge to another.
The pitch or slope of a roof is calculated by dividing the vertical rise by its horizontal span.
A pitched roof is different to a flat roof in several ways: (1) a flat roof has a slope below 10o, whereas a pitched roof usually has a slope equivalent to a gradient of 1:40 to 1:80 and (2) pitched roofs are constructed from slate and tile, whereas modern day flat roofs are built from GRP and single ply.
Types of pitched roof
Pitched roof designs exist in many forms:
Mono-pitched roofs have a slope from one side to another. A simple design is popular with modern day buildings as much as Victorian ones. During construction, rafters are secured to adjacent walls at both sides, prior to supporting the roof covering.
A couple pitched roof is a type that has two timber rafters connected together at a central location (usually the top). A pitched slope is then created to and a relevant roof covering is applied.
CLOSED COUPLE ROOF
Closed couple roofs are created by installing timber beams that run horizontal to the couple roof. This makes the roofing structure more secure. Joists used in the process make the wall less prone to deflection and can increase the span of the roof.
Collar roofs are created by increasing the height of the ceiling joists above the rafter base. This allows rooms to be built in the roofing space – often as part of conversions.
Purlin roofs are a form of pitched roof that use the rafters and walls to support roof decking. This means that the roof span can be increased without affecting wall stability.
The installation of a truss offers wider roofing spans to be built. In modern-day houses, a trussed rafter is used to accommodate various different pitch angles. The rafter itself is made by adding tension and compression in the shape of the truss.
The most common types of covering for pitched roofs are made from slate and tile. Standard roofing accessories include soffits & fascias and gutters & downpipes. If you are planning to build your own pitched roof, please take care and follow relevant health and safety guidelines.Contact a roofing specialist