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Questions and Answers
What is one of the primary purposes of a roof?
What is one of the primary purposes of a roof?
Which of the following is NOT a requirement of a good roof?
Which of the following is NOT a requirement of a good roof?
What type of roof is defined as having a sloping design?
What type of roof is defined as having a sloping design?
Which material is commonly used for roof coverings?
Which material is commonly used for roof coverings?
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What must be provided to avoid weather-related problems for a roof?
What must be provided to avoid weather-related problems for a roof?
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Which of the following roofing types is determined by climatic conditions and construction materials available?
Which of the following roofing types is determined by climatic conditions and construction materials available?
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What aspect of a roof helps in draining out water effectively?
What aspect of a roof helps in draining out water effectively?
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Which of these is considered a secondary function of a roof?
Which of these is considered a secondary function of a roof?
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What is the maximum span of a couple roof?
What is the maximum span of a couple roof?
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Which roof type is specifically designed to support spans up to 4.2m and includes a king rod for sag prevention?
Which roof type is specifically designed to support spans up to 4.2m and includes a king rod for sag prevention?
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What type of roof uses intermediate supports called purlins when the span exceeds about 2.4m?
What type of roof uses intermediate supports called purlins when the span exceeds about 2.4m?
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In which type of roof are rafters supported by being nailed to both a ridge piece and wall plates?
In which type of roof are rafters supported by being nailed to both a ridge piece and wall plates?
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What is the primary purpose of the tie beam in a collar beam roof?
What is the primary purpose of the tie beam in a collar beam roof?
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Which type of truss is suitable for spans between 5m to 8m?
Which type of truss is suitable for spans between 5m to 8m?
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What characterizes a lean-to-roof?
What characterizes a lean-to-roof?
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What is a potential disadvantage of using a couple close roof for larger spans?
What is a potential disadvantage of using a couple close roof for larger spans?
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What does the term 'span' refer to in the context of pitched roofs?
What does the term 'span' refer to in the context of pitched roofs?
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Which of the following best defines 'hip' in pitched roofs?
Which of the following best defines 'hip' in pitched roofs?
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What is the role of purlins in pitched roofs?
What is the role of purlins in pitched roofs?
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Which element of a pitched roof is described as the inclined members running from the ridge to the eaves?
Which element of a pitched roof is described as the inclined members running from the ridge to the eaves?
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What defines a 'gable roof'?
What defines a 'gable roof'?
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Which of the following describes a 'valley' in pitched roofs?
Which of the following describes a 'valley' in pitched roofs?
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What is the purpose of a fascia board in pitched roofs?
What is the purpose of a fascia board in pitched roofs?
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What is a 'gambrel roof' characterized by?
What is a 'gambrel roof' characterized by?
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What is the primary purpose of struts in roof truss systems?
What is the primary purpose of struts in roof truss systems?
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Which type of roof truss is suitable for spans up to 18 meters?
Which type of roof truss is suitable for spans up to 18 meters?
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What is the distinctive feature of a truncated truss compared to a mansard truss?
What is the distinctive feature of a truncated truss compared to a mansard truss?
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Under what conditions do steel trusses become preferred over timber trusses?
Under what conditions do steel trusses become preferred over timber trusses?
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Which of the following is a requirement for a thatch covering to effectively drain water?
Which of the following is a requirement for a thatch covering to effectively drain water?
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What is one characteristic of wood shingle roofing?
What is one characteristic of wood shingle roofing?
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What factors influence the selection of roof covering materials?
What factors influence the selection of roof covering materials?
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What type of framework is typically used to support thatch covering?
What type of framework is typically used to support thatch covering?
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What are tiles primarily made of?
What are tiles primarily made of?
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What is the spacing recommended for common rafters when laying tiles?
What is the spacing recommended for common rafters when laying tiles?
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What material is used to manufacture asbestos cement sheets?
What material is used to manufacture asbestos cement sheets?
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What is the recommended maximum spacing for unsupported A.C. sheets?
What is the recommended maximum spacing for unsupported A.C. sheets?
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What characteristic is necessary for slates used in roofing?
What characteristic is necessary for slates used in roofing?
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How are Galvanized Iron sheets different from Asbestos Cement sheets?
How are Galvanized Iron sheets different from Asbestos Cement sheets?
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What makes Pre-painted Galvanized Iron (PPGI) sheets more corrosion-resistant than normal CGI sheets?
What makes Pre-painted Galvanized Iron (PPGI) sheets more corrosion-resistant than normal CGI sheets?
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What is a characteristic of Pre-painted Galvalume (PPGL) sheets compared to Pre-painted Galvanized Iron (PPGI) sheets?
What is a characteristic of Pre-painted Galvalume (PPGL) sheets compared to Pre-painted Galvanized Iron (PPGI) sheets?
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Study Notes
Roofs and Roof Coverings
- A roof is the uppermost part of a building, providing structural coverings to protect the building from weather.
- Roof structures are composed of structural elements that support the roof coverings.
- Structural elements include trusses, beams, and slabs.
- Roof coverings include C.G.I sheets, PPGL sheets, shingles, slate, etc.
Roof Types
- Pitched or sloping roofs
- Flat or terraced roofs
- Curved roofs
Requirements of a Good Roof
- Adequate strength and stability to support dead and live loads
- Effective protection against weather
- Water-proof with effective drainage
- Adequate thermal and sound insulation
- Fire resistant
Elements of a Pitched Roof
- Span: Distance between supports of an arch or roof truss
- Rise: Vertical distance between the top of the ridge and the wall plate
- Pitch: Inclination of sides of the roof to the horizontal plane
- Ridge: Apex line of the sloping roof
- Eaves: Lower edge of the inclined roof surface
- Hip: Intersection of two sloping surfaces, exterior angle greater than 180°
- Valley: Intersection of two roof surfaces, exterior angle less than 180°
- Hipped End: Sloped triangular surface
- Ridge Piece, Ridge Beam, or Ridge Board: Horizontal members at the apex of a roof truss
- Common Rafters or Spars: Inclined members from the ridge to the eaves
- Purlins: Horizontal members supporting common rafters
- Hip Rafters: Sloping rafters forming the hip of a sloped roof
- Eaves Board or Fascia Board: Wooden boards fixed to the feet of common rafters at the eaves
- Wall Plates: Members on top of brick walls for fixing common rafters
- Batten: Thin strips of wood nailed to rafters for laying roofing materials
- Truss: Frame supporting the roof coverings
Different Forms of Pitched Roofs
- Lean-to-roof
- Gable Roof
- Hip Roof
- Gambrel Roof
- Mansard Roof
- Deck Roof
Various Roof Types
- Single roof: Consists of rafters supported at the ridge and eaves, limited to a span of 5m.
- Couple roof: Formed by a pair of rafters sloping in both directions, upper ends on ridge piece and lower ends on wall plates, limited to a span of 3.6m.
- Couple close roof: Similar to a couple roof, but the lower ends are connected by a tie beam, suitable for spans up to 4.2m.
- Collar beam roof: Used when loads are high; tie beam is placed at 1/3rd or ½ of vertical height from wall plate, suitable for spans up to 5m.
- Double or Purlin Roofs: Introduced for wider spans (greater than 2.4m) to reduce the size of rafters, and support them with purlins.
- Trussed roofs: Framed structures (trusses) are employed for spans above 5m, various types like king-post, queen-post, or combinations of these.
- Mansard Roof Truss: Named after its designer, it is a combination of king-post and queen-post trusses, with pitched portions at different angles; upper portion 30° -40°, lower portion 60° -70°.
- Truncated Truss: Similar to Mansard, but the top is flat, used when a room is needed.
- Steel roof trusses: Preferred for spans exceeding 10m as timber trusses become uneconomical. Various types depend on span, such as king-post, raised chord, scissors, king post, raised chord, and simple Fink trusses.
Roof Coverings
- Thatch Coverings: Common in villages, using bamboo rafters and bundles of reeds or straw.
- Wood Shingle Roofing: Thin wood slabs from seasoned timber.
- Tile Roofing: Made of clay or concrete, with projections (nibs) used for fastening to the battens.
- Asbestos Cement Sheets (A.C. sheets): Larger than tiles, easier installation, 150mm end lap; 1.5 corrugation or 100mm side lap.
- Slate Roofing: Durable and hard, not absorbent, laid in overlapping courses.
- Corrugated Galvanized Iron Sheets (C.G.I sheets): Strengthened by galvanization with zinc, laid like A.C. sheets.
- PPGI/PPGL sheets: Strong, corrosion resistant sheets laid by using bolts or screws.
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Description
This quiz covers the fundamentals of roofs and roof coverings, including various types of roofs, their structural elements, and the requirements for a good roof. Test your knowledge on terms such as pitched roofs, flat roofs, and the essential characteristics needed for effective roofing.
