2. Piched Roof
• A sloping roof is known as a pitched
roof The definitions of technical
terms used in connection with the
pitched roofs are given below.
1. Truss: The frame work ,usually of
triangles and designed to support the
roof covering or ceiling over room ,
is known as a roof truss
Image credits: www.google.com
3. Technical terms
2. Battens: These are the thin strips of
wood which are fixed on the rafters
or ceiling as shown in fig. They
support the roof ceiling.
3. Cleats: These are small blocks of
wood which are fixed on the trusses
to prevent the sliding of purlins as
shown in fig. Image credits: www.google.com
4. 4. Eaves: The lower edges of a roof which are resting upon or projecting beyond the
supporting, walls are known as the eaves. Sometimes a thin board Of wood is
provided at the eaves to cover the ends of the common rafters. Such a board is
known as an eaves board or facia board as shown in fig. It is usually 25 mm thick
an 250 mm wide.
5. Gable: The triangular upper part of a wall formed at the end of a pitched roof is
known as a gable as shown in fig.
6. Hip: The angle formed at the intersection of two roof slopes is known as the hip
Technical terms
Image credits: www.google.com
5. 7. Pitch: The inclination of sides of a roof to the horizontal plane is known
as the pitch and it can be expressed either in terms of degrees or as a ratio
of rise to span.
8. Purlins: The wooden pieces which are placed horizontally on principal
rafters to carry the common rafters are known as the purlins as shown in
fig
Technical terms
6. 10.Common rafters: These are the intermediate rafters which give support to
the roof covering as shown in fig
11.Principal rafters: These are the inclined members of a truss as shown in fig.
12.Wall Plate: These are the long wooden members which are embedded on
top s to receive the common rafters. They actually connect the walls to the
roof.
Technical terms
7. Types of Pitched roofs
• The pitched roofs are classified into three categories and they are as follows:
1. Single roofs: In this type of roofs, the common rafters are provided to each slope without any
intermediate support.Following are the varieties of single roofs:
(i) Lean-to roof
(ii) Couple roof
(iii) Couple-close roof
(iv) Collar beam roof
(v) Collar and scissors roof.
2. Double or purlin roofs: When the span exceeds about 2.40 m, the necessary size for the rafters
becomes uneconomical.
3. Trussed roofs.
