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Page 1 CHAPTER – 13 ROOFS A roof is defined as the uppermost part of a building which is constructed in the form of a frame work to given protection to the building against rain, heat, snow, wind etc. A roof basically consists of structural elements provided at the top of building for the support of roof coverings. Following are the requirements of well planned roof: (i) It should be durable against the adverse effects of various agencies such as wind, rain, sun etc. (ii) It should grant the desirable insulation against sound and heat. (iii) It should be structurally stable and sound, it should be capable of taking the loads likely to come over it. (iv) It should be well-drained (v) It should have efficient water-proofing arrangement. 13.1 Types of roofs-Methods of construction: The roofs classified into the following three categories; (i) Pitched roofs (ii) Flat roofs (iii) Curved roofs I. Pitched roofs: A sloping roof is known as pitched roof as shown in the fig 13.1. The technical terms in connection with the pitched roof are given below Page 2 CHAPTER – 13 ROOFS A roof is defined as the uppermost part of a building which is constructed in the form of a frame work to given protection to the building against rain, heat, snow, wind etc. A roof basically consists of structural elements provided at the top of building for the support of roof coverings. Following are the requirements of well planned roof: (i) It should be durable against the adverse effects of various agencies such as wind, rain, sun etc. (ii) It should grant the desirable insulation against sound and heat. (iii) It should be structurally stable and sound, it should be capable of taking the loads likely to come over it. (iv) It should be well-drained (v) It should have efficient water-proofing arrangement. 13.1 Types of roofs-Methods of construction: The roofs classified into the following three categories; (i) Pitched roofs (ii) Flat roofs (iii) Curved roofs I. Pitched roofs: A sloping roof is known as pitched roof as shown in the fig 13.1. The technical terms in connection with the pitched roof are given below Roofs Fig 13.1 Building with pitched roof (i) Barge Boards: Wooden planks or boards which are fixed on the gable end of the roof (ii) Battens: Thin strips of wood which are fixed on rafters or ceiling to support the roof ceiling. (iii) Cleats: Small blocks of wood which are fixed on truss to prevent the sliding of purlins. (iv) Dragon beam: The diagonal piece of wood which is laid across the corner of the wall. Page 3 CHAPTER – 13 ROOFS A roof is defined as the uppermost part of a building which is constructed in the form of a frame work to given protection to the building against rain, heat, snow, wind etc. A roof basically consists of structural elements provided at the top of building for the support of roof coverings. Following are the requirements of well planned roof: (i) It should be durable against the adverse effects of various agencies such as wind, rain, sun etc. (ii) It should grant the desirable insulation against sound and heat. (iii) It should be structurally stable and sound, it should be capable of taking the loads likely to come over it. (iv) It should be well-drained (v) It should have efficient water-proofing arrangement. 13.1 Types of roofs-Methods of construction: The roofs classified into the following three categories; (i) Pitched roofs (ii) Flat roofs (iii) Curved roofs I. Pitched roofs: A sloping roof is known as pitched roof as shown in the fig 13.1. The technical terms in connection with the pitched roof are given below Roofs Fig 13.1 Building with pitched roof (i) Barge Boards: Wooden planks or boards which are fixed on the gable end of the roof (ii) Battens: Thin strips of wood which are fixed on rafters or ceiling to support the roof ceiling. (iii) Cleats: Small blocks of wood which are fixed on truss to prevent the sliding of purlins. (iv) Dragon beam: The diagonal piece of wood which is laid across the corner of the wall. (v) Eaves: The lower edge of a roof which are resting upon or projecting beyond the supporting walls are known as eave as shown in the fig 13.2 (vi) Gable: The triangular upper part of a wall formed at the end of a pitched roof is known as gable. (vii) Hip: The angle formed at the intersection of two roof slopes is known as hip. (viii) Pitch: The inclination of sides of a roof to the horizontal plane is known as pitch, expressed in degrees or as a ratio of rise to span. (ix) Purlins: The wooden pieces which are placed horizontally on principal rafters to carry the common rafters are known as purlins. (x) Rafters: There are the pieces of timber which extend from the caves to the ridge a) Common rafters : These are the intermediate rafters, which give support to the roof coverings a shown in the fig 13.2. b) Hip rafters: Which provided at the junction of two roof slopes c) Jack rafters: Any rafters, which is shorter than common rafters is known as Jack Rafters. d) Principal rafters : These are the inclined members of a truss Page 4 CHAPTER – 13 ROOFS A roof is defined as the uppermost part of a building which is constructed in the form of a frame work to given protection to the building against rain, heat, snow, wind etc. A roof basically consists of structural elements provided at the top of building for the support of roof coverings. Following are the requirements of well planned roof: (i) It should be durable against the adverse effects of various agencies such as wind, rain, sun etc. (ii) It should grant the desirable insulation against sound and heat. (iii) It should be structurally stable and sound, it should be capable of taking the loads likely to come over it. (iv) It should be well-drained (v) It should have efficient water-proofing arrangement. 13.1 Types of roofs-Methods of construction: The roofs classified into the following three categories; (i) Pitched roofs (ii) Flat roofs (iii) Curved roofs I. Pitched roofs: A sloping roof is known as pitched roof as shown in the fig 13.1. The technical terms in connection with the pitched roof are given below Roofs Fig 13.1 Building with pitched roof (i) Barge Boards: Wooden planks or boards which are fixed on the gable end of the roof (ii) Battens: Thin strips of wood which are fixed on rafters or ceiling to support the roof ceiling. (iii) Cleats: Small blocks of wood which are fixed on truss to prevent the sliding of purlins. (iv) Dragon beam: The diagonal piece of wood which is laid across the corner of the wall. (v) Eaves: The lower edge of a roof which are resting upon or projecting beyond the supporting walls are known as eave as shown in the fig 13.2 (vi) Gable: The triangular upper part of a wall formed at the end of a pitched roof is known as gable. (vii) Hip: The angle formed at the intersection of two roof slopes is known as hip. (viii) Pitch: The inclination of sides of a roof to the horizontal plane is known as pitch, expressed in degrees or as a ratio of rise to span. (ix) Purlins: The wooden pieces which are placed horizontally on principal rafters to carry the common rafters are known as purlins. (x) Rafters: There are the pieces of timber which extend from the caves to the ridge a) Common rafters : These are the intermediate rafters, which give support to the roof coverings a shown in the fig 13.2. b) Hip rafters: Which provided at the junction of two roof slopes c) Jack rafters: Any rafters, which is shorter than common rafters is known as Jack Rafters. d) Principal rafters : These are the inclined members of a truss Roofs (xi) Ridge: A wooden piece provided at the ridge line of a sloping roof is known as ridge or ridge board or ridge piece (xii) Span: The horizontal distance between the internal faces of walls or supports is known as span or clear span. (xiii) Template: A bidding block generally provided at the end of a truss. This block is known as template and it helps in spreading load over a large area. A template may be of wood or stone or R.C.C. (xiv) Verge: The edge of a gable, running between the caves and ridge is known as a verge (xv) Valley: When two roof surfaces meet together and form an internal angle, a valley is formed (xvi) Wall-plate: These are long wooden members which are embedded on top of walls to receive the common rafters Fig 13.2 Truss Page 5 CHAPTER – 13 ROOFS A roof is defined as the uppermost part of a building which is constructed in the form of a frame work to given protection to the building against rain, heat, snow, wind etc. A roof basically consists of structural elements provided at the top of building for the support of roof coverings. Following are the requirements of well planned roof: (i) It should be durable against the adverse effects of various agencies such as wind, rain, sun etc. (ii) It should grant the desirable insulation against sound and heat. (iii) It should be structurally stable and sound, it should be capable of taking the loads likely to come over it. (iv) It should be well-drained (v) It should have efficient water-proofing arrangement. 13.1 Types of roofs-Methods of construction: The roofs classified into the following three categories; (i) Pitched roofs (ii) Flat roofs (iii) Curved roofs I. Pitched roofs: A sloping roof is known as pitched roof as shown in the fig 13.1. The technical terms in connection with the pitched roof are given below Roofs Fig 13.1 Building with pitched roof (i) Barge Boards: Wooden planks or boards which are fixed on the gable end of the roof (ii) Battens: Thin strips of wood which are fixed on rafters or ceiling to support the roof ceiling. (iii) Cleats: Small blocks of wood which are fixed on truss to prevent the sliding of purlins. (iv) Dragon beam: The diagonal piece of wood which is laid across the corner of the wall. (v) Eaves: The lower edge of a roof which are resting upon or projecting beyond the supporting walls are known as eave as shown in the fig 13.2 (vi) Gable: The triangular upper part of a wall formed at the end of a pitched roof is known as gable. (vii) Hip: The angle formed at the intersection of two roof slopes is known as hip. (viii) Pitch: The inclination of sides of a roof to the horizontal plane is known as pitch, expressed in degrees or as a ratio of rise to span. (ix) Purlins: The wooden pieces which are placed horizontally on principal rafters to carry the common rafters are known as purlins. (x) Rafters: There are the pieces of timber which extend from the caves to the ridge a) Common rafters : These are the intermediate rafters, which give support to the roof coverings a shown in the fig 13.2. b) Hip rafters: Which provided at the junction of two roof slopes c) Jack rafters: Any rafters, which is shorter than common rafters is known as Jack Rafters. d) Principal rafters : These are the inclined members of a truss Roofs (xi) Ridge: A wooden piece provided at the ridge line of a sloping roof is known as ridge or ridge board or ridge piece (xii) Span: The horizontal distance between the internal faces of walls or supports is known as span or clear span. (xiii) Template: A bidding block generally provided at the end of a truss. This block is known as template and it helps in spreading load over a large area. A template may be of wood or stone or R.C.C. (xiv) Verge: The edge of a gable, running between the caves and ridge is known as a verge (xv) Valley: When two roof surfaces meet together and form an internal angle, a valley is formed (xvi) Wall-plate: These are long wooden members which are embedded on top of walls to receive the common rafters Fig 13.2 Truss Types of pitched roofs: (i) Single roof (ii) Double or purlin roof (iii) Trussed roofs (i) Single roof: In this type of roofs, common rafters are provided to each slope without any intermediate support. The following are the varieties of single roof. a) Lean to roof b) Couple roof c) Couple close roof d) Collar beam roof a) Lean to roof: It is the simplest form of a pitched roof and it is known as pent roof or Aisle roof. In this type of roof, one wall is carried up sufficiently higher than the other to give necessary slope to the roof. A lean-to roof is generally used for sheds, out-houses attached to main buildings verandah etc. This is suitable for a maximum span of 2.40m as shown in fig 13.3.Read More
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