BUILDING CONSTRUCTION II ECM 3154 WEEK 7 ROOFS

BUILDING CONSTRUCTION II ECM 3154 WEEK 7 ROOFS – PART 1 Power. Point® Slides by Zamzarina Bt Md. Judyar Last Updated: © LMS SEGi education group 1

CHAPTER OVERVIEW • Last Updated: This chapter brings the student through the introduction of roofs which are focus on history of roofs, functional requirements and various of types of roofs. © LMS SEGi education group 2

LEARNING OBJECTIVES • Last Updated: Students should be exposed to the history, function and various types of roofs. Advantages and disadvantages for each flat roof. © LMS SEGi education group 3

LEARNING OUTCOMES • Last Updated: At the end of lesson, students should be familiar with the vast array of flat roofing systems available and can explain the function of any roofs. Students must be able to know how to read any drawing plan of any flat roofs. © LMS SEGi education group 4

INTRODUCTION • • • Last Updated: From the earliest times, humans and their ancestors sought protection from the elements of nature, changing seasons and predators, in natural shelters such as caves and rock overhangs. Gradually, they learned to improve their caves with inlaid stone floors, walls at the entrances and fireplaces. Ultimately they began creating entirely new habitats in locations that had no natural shelter. © LMS SEGi education group 5

INTRODUCTION • • • Last Updated: Shelters built from natural materials indicates that they had knowledge of the stress, strain and insulation properties (heat, cold and water-proofing) of the materials used. The use of hand-made bricks or stone blocks indicated knowledge of properties such as compression forces. The symmetrical shapes of the designs indicated the knowledge and application of the principles of geometry. © LMS SEGi education group 6

HISTORY OF ROOF • Last Updated: Natural features, caves and overhangs Natural shelters like caves or overhangs were used as homes. Little or no building materials were used. © LMS SEGi education group 7

HISTORY OF ROOF • Last Updated: Crude shelter Temporary structures that needed little workmanship. Materials found nearby were used and arranged on a crude framework of branches. © LMS SEGi education group 8

HISTORY OF ROOF • Last Updated: Beehive hut A typical building style of the Nguni people (Zulu and Xhosa). Vertical branches were stabilised with horizontal bracing with no distinction between the walls and the roof. The sapling structure was bound together by grass fibre ropes and the grass covering was 'sewn' to the structure with grass rope. © LMS SEGi education group 9

HISTORY OF ROOF • Last Updated: Cone on cylinder A typical style among the Tswana, Sotho and Venda people. The roof is separate and can be clearly identified. The roof was made from grass and the walls from daga or a type of cement © LMS SEGi education group 10

HISTORY OF ROOF • Last Updated: Hipped-on cube Western influence led to the introduction of the 90º wall construction. The wall layout also dictates the shape of the roof. Walls are higher and doorways larger. © LMS SEGi education group 11

DEFINITION • • Last Updated: A roof system consists of a number of interacting materials that when properly combined provide a weather-resistant top surface to a building. In some system roof also insulate the building. © LMS SEGi education group 12

FUNCTION • • Last Updated: To keep out rain, wind, snow & dust To prevent excessive heat loss in winter To keep the interior building cool in summer Designed to accommodate all stresses encountered Designed to accept movement due to changes in temperature & moisture content To provide lateral restraint & stability to adjacent walls To resist penetration of fire & spread of flame from external sources © LMS SEGi education group 13

TYPES OF ROOF Flat Roof Its not perfectly flat Must have a slight slope for drainage • Shed Roof A single slope • Gable Roof 2 slope meeting at ridge. 2 walls extends to the ridge • Hip Roof 2 gable, pyramid should be considered as a hip roof • Last Updated: © LMS SEGi education group 14

TYPES OF ROOF Gambrel Roof 4 slopes in one direction, the typical barn roof • Mansard Roof 2 gambrels Basically is to the gambrel what the hip is to gable • Pitched Roof drains water insulates main area of heat loss support snow load • Last Updated: © LMS SEGi education group 15

shedworld. com allbusiness. com • Last Updated: Shed roof © LMS SEGi education group 16

roof-repair-houston. com sheds-gazebos. com Hip Roof Last Updated: © LMS SEGi education group 17

newenglandbarn. com flat-roof-repair. co. uk Flat Roof & Pitched Roof Last Updated: artistichome. wordpress. com © LMS SEGi education group 18

toolstable. com barntoolbox. com four-sided roof having a double slope on all sides, with the lower slope much steeper than the upper. • Last Updated: Mansard Roof © LMS SEGi education group 19

charlesandhudson. com • Last Updated: s 380. photobucket. com Gambrel Roof © LMS SEGi education group 20

FLAT ROOF Its not perfectly flat, slightly slope which is less than 10°. • This roof is been used in hot climates where water accumulation is not a problem. (less rain) • Last Updated: © LMS SEGi education group 21

WATERPROOFING THE FLAT ROOF • • Last Updated: The flat roof relied on some kind of membrane for keeping moisture out. The slight slope of flat roof directs standing moisture to drains at edges. © LMS SEGi education group 22

TYPES OF FLAT ROOF • Last Updated: Types of flat roof due to material: • i. Timber flat roofs • ii. Asphalt flat roofs • iii. Lead-covered flat roofs • iv. Copper-covered flat roofs © LMS SEGi education group 23

TIMBER FLAT ROOFS • Last Updated: Timber flat roofs are usually constructed to fall in one direction towards a gutter or outlet. © LMS SEGi education group 24

TIMBER FLAT ROOFS Source: www. londonflatroofing. co. uk Last Updated: © LMS SEGi education

ASPHALT FLAT ROOFS Timber flat roof with mastic asphalt covering Source: www. jnroofingandwindow. com Last Updated: © LMS SEGi education group 26

ADVANTAGES OF FLAT ROOF a) b) c) d) Last Updated: Less material is being used than in a sloped roof The rooftop is potentially useful as a terrace or sleeping porch Potentially pleasing appearance Easier to build than a sloped roof © LMS SEGi education group 27

DISADVANTAGES OF FLAT ROOF Roof elements can’t overlap, hence waterproofing must be more complex and more thorough. b) Drainage isn’t automatic. Unless properly designed & constructed, pools of water will collect on the surface causing local variations in temperature. This will result in deterioration of the covering finally leading to high maintenance cost. c) It have little or no space below roof to accommodate services d) It have limited capacity for insulation a) Last Updated: © LMS SEGi education group 28

QUIZZES 1. Differentiate mansard roof and gambrel roof. ……………………………………………………………… 2. Identify any three advantages of flat roof. ……………………………………… Last Updated: © LMS SEGi education group 29

KEY TERMS 1. Lateral restraint Definition Beam restraint that prevents lateral movement of the compression flange. Compression member restraint that prevents lateral movement or twisting of the member. 2. Gutter Definition A trough fixed under or along the eaves for draining rainwater from a roof. Also called regionally eaves spout, eaves trough, rainspout, spouting. 3. Sloped roof Definition The roof's pitch is the measured vertical rise divided by the measured horizontal span, the same thing as what is called "slope" in geometry. Last Updated: 2/14/2018 © LMS SEGi education group 30

REFERENCES • • Last Updated: Chudley, R. , & Greeno, R. , 2005. Construction Technology, 4 th ed. England: Pearson. Chudley, R. , & Greeno, R. , 2001. Advanced Construction. Technology, 3 rd ed. England: Longman. Spence, W. , D. , 2006. Construction Materials, Methods, and Techniques, 2 nd ed. US: Delmar. shedworld. com retrieved 18 th August 2011 allbusiness. com retrieved 18 th August 2011 roof-repair-houston. com retrieved 18 th August 2011 sheds-gazebos. com retrieved 18 th August 2011 flat-roof-repair. co. uk retrieved 18 th August 2011 © LMS SEGi education group 31

REFERENCES • toolstable. com retrieved 18 th August 2011 • newenglandbarn. com retrieved 18 th August 2011 • artistichome. wordpress. com retrieved 18 th August 2011 • • • Last Updated: barntoolbox. com retrieved 18 th August 2011 charlesandhudson. com retrieved 18 th August 2011 s 380. photobucket. com retrieved 18 th August 2011 Source: www. londonflatroofing. co. uk retrieved 18 th August 2011 www. jnroofingandwindow. com retrieved 18 th August 2011 © LMS SEGi education group 32