Construction Technology 1: Low Rise Housing Construction

Course Overview

• CT 1 focuses on applying scientific knowledge for low-rise construction, while CT 2 focuses on high-rise construction
• Designing for the inhabitant involves considering the end-user's needs, including durability, flexibility, insulation, protection, structural stability, sustainability, aesthetics, resilience, quality, safety, and health and wellbeing

Designing for the Inhabitant

• To make a house a home, factors such as durability, flexibility, insulation, protection, structural stability, sustainability, aesthetics, resilience, quality, safety, and health and wellbeing should be considered
• Structural stability involves designing buildings to resist forces applied to them
• AS1684 timber framing manual is used throughout the course

Construction Process

• Site investigation involves assessing the ground's composition and characteristics to choose a compatible foundation
• Site visit provides insight into ground conditions, natural bodies of water, and nearby obstacles
• Site condition report details potential difficulties, including existing services, legal issues, and site conditions

Types of Homes

• Resilient homes are designed for long-term durability, considering factors like bushfires, high winds, and floor loads
• Sustainable homes are designed for sustainability, incorporating features like solar panels, batteries, and rainwater tanks
• Reliable homes are designed for ease of mind, with high-quality materials and robust building warranties
• Liveable homes prioritize occupant wellbeing, with access to green outdoor spaces and community gardens
• Healthy homes are designed to promote occupant health, using non-toxic, natural, and safe materials

Timber Construction

• Brick piers are built on top of concrete pad footings to a certain height, with framing sitting level on top
• Ant capping is used to force termites to go around the piers, helping to find and prevent damage
• Bearers are timber beams placed on top of piers, spaced at around 1800mm and spanning 1800mm
• Joists are placed on top of bearers, spaced at 450mm or 600mm, with a span of around 1800mm
• Flooring is placed on top of joists, creating a subfloor space for maintenance, termite inspections, and ventilation

Roofing and Wall Frames

• Wall frames consist of columns (studs) held together by top and bottom plates, with noggins in between to prevent buckling
• Lintels are used for spanning openings for doors and windows, taking loads from the roof
• Roofing involves prefabricated roof trusses, with a structure including rafters, ceiling joists, and ridge boards

Soil and Footings

• Soil bearing capacity is the ability of soil to carry the load of a building and its contents without excessive settlement
• Volume changes in soil can result in serious damage to footings and buildings
• Footing systems must be selected to suit the anticipated volume change in the soil
• Soil types include rock, sand, clay, and problem sites, each with unique characteristics and challenges

Slabs and Footings

• Stiffened raft slabs consist of concrete beams and floors across the entire floor plan, with a 100mm thick concrete slab and steel reinforcement

• Strip footings are also known as reinforced concrete footings, usually continuous around the entire perimeter of the building

• Waffle slabs are formed on top of the ground using a polystyrene grid, with advantages including reduced concrete and steel usage

• Slab on ground involves both conventional and waffle slabs, with an edge rebate for brickwork in brick veneer type construction### Construction Safety on Residential Buildings

• Biggest cause of death in construction: falling from height

• High-risk activities: height, moving plant and machinery, working under small margins with high production pressures

Hazards

• Chemical hazards: gases, dusts, fumes, vapours, liquids, acids, corrosiveness, petrol, flammability, oil, slippery
• Biological hazards: bacterial, viruses, mould, insects, vermin, animals, and animal products
• Psychosocial hazards: stress, fatigue, bullying, long working hours, intensive work, job insecurity, lack of work-life balance
• Physical and ergonomic hazards: cluttered access routes, badly designed workstations, rung missing from a ladder, heavy box, mass, back strain from lifting
• Safety-related hazards: working at height, falling objects, collapsing structures
• Health-related hazards: asbestos, toxic fumes, psychosocial hazards

Controlling Risks at the Workplace

• Hierarchy of control:
  • Level 1: Eliminate (physical removal of the hazard, very high protection)
  • Level 2: Substitute (swapping something dangerous for something less dangerous, high protection)
  • Level 3: Isolation (engineering controls, medium-high protection)
  • Level 4: Administrative controls (changes to the way people work, moderate protection)
  • Level 5: PPE (personal protective equipment, low protection)

OHS Performance Measurement

• Measurement assists in controlling risks by providing information on how the system operates in practice, identifying areas for remedial action, and providing a basis for continuous improvement
• OHS performance indicators:
  • Lagging indicators: number/rate of incidents, costs of losses, historical, trailing
  • Leading indicators: current performance, predictors of future safety performance, upstream, predictive, positive

Managing Risk

• Risk assessment, Safe Work Method Statement (SWMS), Job Safety Analysis (JSA), Safe Operating Procedure (SOP), and ‘Take 5’ are methods used to manage risk in the construction industry
• Managing risk involves not only documenting a safe plan but also executing it with the people around us

Critical Health and Safety Behaviours

• Case example reporting limitations
• Categories of critical health and safety behaviours

Construction Safety Risks

• Housekeeping: managing activities to ensure safe movement around the site, designated walkways, appropriate footwear, reporting risks
• Manual handling: minimizing bodily force when using materials/interacting with machinery, mechanical leads
• Work at height: biggest cause of serious and fatal injury, roof work, mobile platforms, scaffolding, ladders, rope, applied controls to prevent/restrict/mitigate falls
• Structures and excavations: risk of unintentional collapse, structural support
• Lifting operations: proper planning and supervision, cranes and lifting accessories, trained and competent operators
• Electrical safety: safe and properly maintained, live systems can be worked on by a qualified and authorized person
• Mobile plant and vehicles: qualified operators, attention to access requirements and restrictions
• Permits to work: required for some sites, eg.### Water Resistance
• Load-bearing element is not the brickwork but the timber frame
• Weep holes are used for drainage and ventilation to reduce the risk of rot and dampness
• Weep holes protect timber framing from a structural perspective

Foundation Options

• Screw piles: flexible, fast, and cost-effective foundation option
• Screw piles are screwed into the ground using a hydraulic attachment on machines such as excavators
• Stump pad footing: simplest and most familiar footing used for vertical support and transfer of building loads to the foundation
• Stump pad footing is used to support timber-framed houses
• Timber, concrete, and steel can be used for stumps
• Concrete/timber footing is placed under the base of the stump to spread the load transferred from the building

Sub-Floor Construction

• Bearers: first of the sub-floor frame members to be installed, positioned over stumps, piers, or other supports
• Floor joists: typically run over bearers
• Sub-floor: analysis assumes joists carry a uniformly distributed load (UDL)
• Bearers carry point loads
• Platform floors: provide a working platform for the builder, laid before erecting the wall and roof framing

Wall Framing

• Wall systems: timber stud wall frame is the most common in Australia
• Wall framing: non-load-bearing walls do not support loads from the building besides their own weight
• Load-bearing walls bear some of the building's weight as well as their own weight
• Bottom plate: carries the stud loads to the floor joints
• Top plate: built along the full length of all walls, including over openings
• Bracing: provides lateral support to wall framing, attached to studs

Roofing

• Roof types: hip, valley, gable, hipped, hipped with Dutch gabled, skillion
• Ceiling joists: provide structure onto which the ceiling is fixed, connect to the lower ends of rafters, preventing spreading and sagging
• Hanging beams: reduce the span of ceiling joists, allowing for more economic joist size and consistent section
• Struts and strutting beams: transfer loads from underpurlins and other beams to load-bearing walls
• Collar tie: a tension tie resisting rafter separation during periods of unbalanced loads
• Ridgeboard: a non-load-bearing member used as a platform for rafters to rest against and connect to

Cladding Systems

• Cladding systems: enclose the building and provide protection from the weather
• External cladding contributes to the comfort, structural adequacy, and aesthetics of a building

Construction Sequence

• Site preparations
• Final prep for pour
• Slab poured
• Wall framing set out
• Wall framing erected
• Fascia, guttering, and trusses installed
• Roof ties installed
• Sisalation and windows/doors installed
• Brickwork
• Services
• Insulation
• Plastering
• Internal doors
• Painting
• Brickwork painted
• Flooring and fixtures

Fixtures and Fittings

• Fixtures: items secured and bolted (lighting, sockets, built-in wardrobes)
• Fittings: free-standing items (microwave, furniture, oven)

Categories of a Home

• The resilient home: designed for longevity, durability, and against natural disasters
• The sustainable home: focuses on sustainability, circularity, and waste systems
• The reliable home: ensures high-quality and reliable products, functionality, and flexibility
• The liveable home: focuses on occupants' wellbeing, access to green outdoor spaces, and community engagement
• The healthy and safe home: prioritizes health and safety, creating healthy living through material choices and ventilation