How many Types of Pitched Roofs
Types of Pitched Roof
Pitched roofs may broadly be classified into the following

- Single roofs
- Lean-to roof (verandah roof)
- Couple roof.
- Couple-close roof.
- Collar beam roof or collar tie roof.
- Double or purlin roofs
- Triple-membered or framed or trussed roofs
- King-post roof truss.
- Queen-post roof truss.
- Combination of king-post and queen-post trusses,
- Mansard roof truss.
- Truncated roof truss.
- Bel-fast roof truss or latticed roof truss.
- Composite roof trusses.
- Steel sloping roof trusses.
Single Pitched Roofs
- Single roofs consist of only community rafters which do secure at the ridge and also wall plate.
- These are used when the span is weak so that no intermediate support is needed for the rafters.
Lean-to-roof
- This is the simplest type of sloping roof while which rafters slope to one party only.
- A wooden wall plate is supported either on a steel corbel or a stone corbel, which are provided at 1 m middle to middle.
- The wall plate is implanted on the opposite side, to the wall or pillars.
- The difference in elevation between the two surface plates is so held that the coveted slope is obtained. The natural slope is 30°.
- The common rafters are nailed to wooden partition plates on their upper end.
- This type of roof is suitable for a maximum span of 2.5 m.
- These are provided for sheds, outhouses attached to the main building, verandahs, etc.

Couple roof
- This type of roof is formed by a couple or pair of rafters that slope to both sides of the ridge of the roof.
- The upper ends of each pair of the rafter are nailed to a common ridge piece and their lower ends are notched and nailed to the wooden wall plates embedded in the masonry on the top of the outer walls.
- Single couple roof is done when the span is limited so 3.6 meters.

Couple close roof
- A couple of close roofs are similar to the couple roof, except that the ends of a couple of common rafters are connected by a horizontal member, called a tie beam, to prevent the rafters from spreading and thrusting out of the wall.
- The tie beam may be a wooden member or a steel rod.
- The connection between the wooden tie and the feet of the rafters is obtained by the dovetail halved joint.
- Some couple-close roof is economically becoming for span up to 4.80 m.

Collar beam roof
- When the spread increases, or during the load is more, the rafters of the couple nearby roof tend to bend.
- This is avoided by raising the tie beam and fixing it at one-third back one-half of this vertical height from the wall plate so the ridge.
- That raised beam is known as a single collar beam or collar tie.
- This roof is suitable to an extent of up to 5 m.

Collar and scissors roof
- It is comparable to the collar roof, except that to collar beam crossing is very different to have the appearance of scissors, is provided.

A double or purlin roof
- A double roof is one in which purlins are introduced to support the common rafters at an intermediate point.
- Before-mentioned roofs are used during the span exceeds 5 metres.
- The function of a purlin is to tie the rafters together and to act as intermediate support to the rafters.
- These roofs have two basic elements
- Rafters, and
- Purlins.
- The intermediate supports so provided in the form of purlins, reduce the size of the rafters to the economical range.
- Each beam is thus supported at 3 points
- At this bottom; on the wall into the wall plate,
- At each top, near the ridge beam, and
- In the middle by a purlin.

Trussed Roofs
- When the span of the roof exceeds 5 m and where there are no inside walls to support the purlins, then trusses are provided at suitable intervals along the length of the room.
- Spacing is generally limited to 3.0 metres for wooden trusses.
- A triplex branch or trussed roof consists of 3 sets of members
- Common rafters,
- Purlins, and
- Trusses.
- The purlins, which give intermediate support to the rafters, are themselves supported on trusses that are suitably spaced along the length of a room.
- A trussed roof is provided during the length of each room is large.