Unit 6: Building Technology in Construction Learning Outcome Understand the techniques used in the construction of superstructures for low-rise domestic and commercial buildings Lesson Objective To be able to explain the techniques used for construction of roofs in commercial construction

Unit 6: Building Technology in Construction Commercial Roof Construction

Unit 6: Building Technology in Construction Flat roofs are those whose slope is less than 10 degrees Pitched roofs have slopes greater than 10 degrees. Roof Construction

Unit 6: Building Technology in Construction Roof Construction

Unit 6: Building Technology in Construction Roof Construction

Unit 6: Building Technology in Construction Pitched Roof Materials: SHINGLES: asphalt, sawn wood, shakes, slate, clay tiles or concrete tiles THATCH: bundles of leaves, reeds or grasses and bracken ARCHITECTURAL SHEET METAL: lead, copper, aluminium and terne (stainless steel or sheet steel) with flat or standing seams Roof Construction

Unit 6: Building Technology in Construction Roof Construction Metal Roofing

Unit 6: Building Technology in Construction Kalzip roof liner Roof Construction

Unit 6: Building Technology in Construction 3D Animation – Kalzip Roof Construction

Unit 6: Building Technology in Construction Metal Roof: Standing Seam Roof Construction

Unit 6: Building Technology in Construction Metal Roof: Standing Seam Roof Construction Kalzip clip

Unit 6: Building Technology in Construction Flat or Low Slope Roofs: PRIMARY COMPONENTS: structural roof deck thermal insulation vapour retarder (and air barrier) waterproof membrane Roof Construction

Unit 6: Building Technology in Construction Structural Roof Deck: must be designed to minimize deflection to reduce ponding and minimize drainage either slope roof deck or taper insulation to drain roof usual materials are: –plywood –wood decking –cast or hollow core concrete –steel decking Roof Construction

Unit 6: Building Technology in Construction Thermal Options WARM ROOF – Insulation above deck and vapour control below roof covering, therefore deck and ceiling temperature near internal temperature. INVERTED – Insulation above the roof covering, therefore roof covering, deck and ceiling at a temperature close to that of the internal building. COLD – Insulation placed immediately above the ceiling, therefore roof covering and structural deck much colder than interior Roof construction

Unit 6: Building Technology in Construction Roof construction Warm Roof: Insulation BETWEEN the Deck and the Membrane: Traditional location for insulation: use low density rigid panels to support the loads on the roof membrane without allowing puncture of membrane any water vapour trapped in insulation will cause deck to rot so use topside vents to relieve pressure

Unit 6: Building Technology in Construction Roof construction Inverted: Insulation ABOVE the Membrane: Advantages: membrane protected from extremes of heat and cold, is on the warm side of the insulation membrane protected from UV radiation membrane protected from puncture insulation must be extruded polystryrene foam board which is water resistant and covered with a filter layer to prevent migration of ballast

Unit 6: Building Technology in Construction Roof construction

Unit 6: Building Technology in Construction Waterproof covering materials: Roofing Membranes THREE PRIMARY TYPES: 1.conventional (bituminous built up roofing or BUR) 2.prefabricated sheets – single ply membranes eg Sarnafil 3.cast in situ – eg Permaquik Roof construction

Unit 6: Building Technology in Construction Loose laid, ballasted, membrane

Unit 6: Building Technology in Construction What are the requirements of roofing membranes? tensile strength elongation crack bridging fatigue resistance thermal shock tear resistance abrasion resistance lap joint integrity static puncture impact resistance low temp. flexibility weatherability heat aging dimensional stability membrane attachment flashing attachment materials compatibility wind uplift resistance Roof construction These requirements apply to conditions during manufacture, during installation and in the field in service.