Untitled Quiz
54 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the first step in determining the NCC building classification compliance pathway?

  • Select a compliant solution
  • Identify the arrangement of SOUs
  • Determine noise insulation requirements
  • Determine NCC class (correct)

    • Which materials can be used to improve acoustic performance according to noise resistance strategies?

  • Doors with no sealing features
  • Glass and wood paneling
  • Rigid connections and thin drywall
  • Mineral wool and thick carpets (correct)

    • What is the primary concern regarding windows and doors from an acoustic performance perspective?

  • They often act as weak spots in noise resistance (correct)
  • They should be made of lightweight materials
  • They are usually strong points for noise insulation
  • They require no specific sealing measures

    • Which type of NCC construction provides the highest level of passive protection?

    <p>Type A</p> Signup and view all the answers

    Which component of fire resistance refers to the ability to contain smoke and flames?

    <p>Integrity</p> Signup and view all the answers

    What does a building need to successfully safeguard occupants in the event of a fire?

    <p>Clear evacuation routes</p> Signup and view all the answers

    What is the purpose of isolation joints in construction?

    <p>To accommodate movement without restraint</p> Signup and view all the answers

    Which factor must be considered when designing basement structures?

    <p>Hydrostatic pressure from groundwater</p> Signup and view all the answers

    What is a critical factor in the approach to selecting wet wall retaining systems?

    <p>Cost vs Performance and Durability</p> Signup and view all the answers

    What does the notation 60/60/60 express in terms of fire resistance?

    <p>Fire resistance levels of building elements</p> Signup and view all the answers

    What is the main goal of incorporating effective fire engineering techniques?

    <p>To replace compartmentalization with effective smoke and gas management</p> Signup and view all the answers

    Which function does a suspended slab above a basement serve?

    <p>A diaphragm to resist horizontal forces</p> Signup and view all the answers

    Which strategy helps improve noise insulation in buildings?

    <p>Isolation of one side of the wall from the other</p> Signup and view all the answers

    In which scenario is waterproofing considered essential?

    <p>Habitable basements</p> Signup and view all the answers

    What is the primary purpose of the NCC?

    <p>To provide flexibility in performance requirements for construction</p> Signup and view all the answers

    Which of the following best describes Sole Occupancy Units (SOU)?

    <p>A section of a building occupied by a single entity</p> Signup and view all the answers

    What is the main function of shoring in construction?

    <p>To retain structures or soil to prevent collapse</p> Signup and view all the answers

    Which type of material is defined as Virgin Excavated Material (VENM)?

    <p>Excavated earth that has not been altered by human activities</p> Signup and view all the answers

    What characteristics make concrete blocks a popular choice in construction?

    <p>Quick placement and no crane required.</p> Signup and view all the answers

    Which of the following statements about control joints is accurate?

    <p>They prevent cracking caused by movement in masonry structures.</p> Signup and view all the answers

    In the context of fire and soundproofing, what should be prevented from spreading beyond the room of ignition?

    <p>Fires</p> Signup and view all the answers

    What is the role of dewatering in construction?

    <p>To stabilize soil and prevent collapse.</p> Signup and view all the answers

    Which method is typically used to ensure reinforced concrete is properly cured?

    <p>Ensuring it is kept damp and at recommended temperatures.</p> Signup and view all the answers

    What is the most common issue concerning fire safety in buildings?

    <p>Noise resistance failures are more frequent than fire incidents.</p> Signup and view all the answers

    What does the code 'N16-400' represent in the context of reinforcing steel?

    <p>The diameter of the bar in millimeters and the spacing between bars.</p> Signup and view all the answers

    Which type of pile is designed to support the footings of building structures?

    <p>Reinforced piles</p> Signup and view all the answers

    What is the purpose of grouting cores in concrete masonry?

    <p>To provide structural support and load-bearing capacity.</p> Signup and view all the answers

    What component is typically used to create a drainage zone in front of a waterproof membrane?

    <p>Gravel backfill</p> Signup and view all the answers

    Which type of membrane allows installation without heating?

    <p>Self adhesive sheet membrane</p> Signup and view all the answers

    Which of the following is a downside of an in-situ reinforced slab?

    <p>Labour intensive construction</p> Signup and view all the answers

    What is the main purpose of using top steel in slabs?

    <p>Control temperature and shrinkage</p> Signup and view all the answers

    For which scenario is back propping particularly used?

    <p>To support slabs until they can bear load</p> Signup and view all the answers

    What characterizes a composite slab?

    <p>Combines precast elements with in-situ formwork</p> Signup and view all the answers

    What type of joint allows for one directional movement while maintaining strength in another?

    <p>Expansion joint</p> Signup and view all the answers

    What is a common failure reason for cavity brick walls?

    <p>High exposure to moisture</p> Signup and view all the answers

    What can excessive vibration during concrete placement cause?

    <p>Separation of aggregate</p> Signup and view all the answers

    Which method utilizes a heat welding technique for seams?

    <p>Torch on membrane system</p> Signup and view all the answers

    What is an advantage of engineered formwork systems?

    <p>Improved safety and speed</p> Signup and view all the answers

    What should not be placed under joints in suspended slabs?

    <p>Water features</p> Signup and view all the answers

    What is typically included in a Bill of Quantities (BoQ)?

    <p>List of items with quantities and rates</p> Signup and view all the answers

    What should be avoided when constructing a wall with different types of bricks?

    <p>Mixing clay and concrete bricks</p> Signup and view all the answers

    Which material is not commonly used for damp proof courses?

    <p>Steel</p> Signup and view all the answers

    What is the primary purpose of weep holes in cavity walls?

    <p>To drain water from the cavity</p> Signup and view all the answers

    What type of bricks are considered low cost but also low strength?

    <p>Calcium silicate bricks</p> Signup and view all the answers

    Which condition should trigger the need for ventilation at the top of a cavity wall?

    <p>Anticipated wind-driven rain</p> Signup and view all the answers

    What feature is critical for the success of cavity walls in preventing water transfer?

    <p>Wall ties</p> Signup and view all the answers

    What should the slope of balconies and flat roofs typically achieve?

    <p>1:60</p> Signup and view all the answers

    What does the membrane classification 'Class 1' indicate?

    <p>Low extensibility</p> Signup and view all the answers

    What is a significant factor when specifying bricks for external walls?

    <p>Absorption rate of the bricks</p> Signup and view all the answers

    Why is a drainage system vital in balcony and roof waterproofing?

    <p>To prevent water ponding</p> Signup and view all the answers

    What is the intended application of a DPC in construction?

    <p>To prevent rising damp</p> Signup and view all the answers

    What causes efflorescence on surfaces?

    <p>Saturation of mortar tile bed</p> Signup and view all the answers

    What feature makes flashings more critical in higher buildings?

    <p>More exposure to moisture</p> Signup and view all the answers

    What characteristic is essential for mortar used in load-bearing walls?

    <p>Appropriate grading</p> Signup and view all the answers

    Study Notes

    ### NCC Explained

    • NCC (National Construction Code) sets minimum standards for building safety, health, amenity, accessibility and sustainability.
    • NCC is not a guarantee of building fitness for purpose.
    • Provides options to achieve compliance through either DTS (Deemed to Satisfy) or performance solutions.
    • Buildings can be designed using reference documents as DTS.
    • Multi-use buildings require classification for each part unless the area is less than 10% of the floor area.
    • A Sole Occupancy Unit (SOU) is a space for one or joint owners/tenants.

    Townhouses and Apartments

    • Townhouses are joined in rows with a common noise/fire wall.
    • Townhouses are often built under strata title due to shared garages, etc.
    • Apartments have more complex fire egress because of shared stairs.

    ### Reinforced Concrete Considerations

    • Ensure formwork is strong, secure, and the correct configuration of reinforcement bars and mesh is used.
    • Maintain correct cover levels to prevent corrosion.
    • Ensure concrete strength is adequate for the design.
    • Vibration and surface finish should be correct.
    • Proper curing is essential for structural integrity.
    • Don't strip formwork before concrete has reached the required strength.

    Planning and Preparation for Construction

    • Understand drawings, specifications and the scope of works.
    • Review geotechnical reports, environmental reports, and shoring designs.
    • Obtain development consent and traffic management plans.
    • Consider site conditions and access requirements.
    • Prepare a bill of quantities (BoQ) and project program.
    • Locate service locations on site.
    • Select specialist subcontractors and plant required for the project.

    Excavation Equipment

    • Excavator: cuts, scoops, carries, and tips materials.
    • Dozer: pushes and rips soil or rock.
    • Drot: multi-use front bucket, can cut, push, load, scrape, tip, and use a clamshell.

    Dewatering

    • The water table is the level where soil is saturated with groundwater.
    • Dewatering is important to stabilize soil and prevent collapse.
    • Techniques include well points and wells.
    • Well points are boreholes with liners and pumps.

    Waste Classification

    • VENM - Virgin Excavated Natural Material
    • ENM - Excavated Natural Material
    • GSW - General Solid Waste
    • Asbestos impacted GSW
    • RSW - Restricted Solid Waste
    • Industrial Waste
    • Hazardous Waste
    • ASS - Acid Sulphate Soil
    • Putrescible Waste

    Shoring and Piling

    • Shoring supports structures or soil to prevent collapse.
    • Piling supports footings for building structures.
    • Reinforced piles with shotcrete infill are a common solution.

    Concrete Blocks

    • Often used as permanent formwork for reinforced concrete structures.
    • Can be reinforced with mild steel rebars.
    • 200mm blocks are commonly used for their versatility.
    • Blocks offer advantages like ease of placement (no crane needed), and resistance to dampness.
    • Waterproofing is relatively easy.
    • Dimensionally stable and economical.

    ### Alternatives to Concrete Blocks

    • Contiguous or Non-Contiguous Piles: quick construction, requires specialized equipment, limited contractor pool.
    • Leave In Place Formwork: quick construction, no specialized equipment, large contractor pool.

    Concrete Masonry

    • Concrete: durable, slightly shrinks, minimal dimensional variation.
    • Masonry: flexible, small units, easy to build.
    • Blocks: structural advantage with reinforcement, unreinforced masonry is weaker under horizontal loads.

    ### Block Sizes

    • 100 series: block size 90mm + 10mm joint

    • 150 series: block size 140mm + 10mm joint

    • 200 series: block size 190mm + 10mm joint

    • 300 series: block size 290mm + 10mm joint

    • 200 Hollow is the most common size (190mm block + 10mm mortar joint = 200 module).

    • 390mm Long blocks (390mm + 10mm mortar joint = 400 module).

    ### Coding Format for Reinforcement Steel

    • N: nominal ductility (500MPa for deformed bar, 250MPa for round bar).

    • Deformed Bar: raised ribs for mechanical grip and shear performance.

    • Round Bars: smooth, used for fitment and ligatures to hold main bars in a cage.

    • N16-400:

      • N = diameter of the bar.
      • 400 = spacing between bars (vertical or horizontal).

    • Splice: overlap amount when tying bars.

    • Cogs and Hooks: bar bends for anchorage into the concrete and cage setup.

    • AS3600-2018: deemed to satisfy NCC requirements.

    Lightweight Concrete Masonry

    • Lighter weight mixes, like 20.01 blocks weighing 11kg at 15MPa.
    • Use of bottom ash from coal fired furnaces or slag sand from steel production.
    • Replacing cement with slagment.

    Mortar Joint

    • Provides even bedding for bricks.
    • Transmits compressive load.
    • Bonds units to carry tensile or shear forces.
    • Clean washed sand is recommended.

    Grouting Cores

    • Grout is poured by hand or pumped into hoppers.
    • Cores must be clean and free from mortar.
    • Openings are sealed with formwork during the pour.
    • Minimize grout pours to prevent ash setting.
    • Minimum grout strength of 12MPa (20MPa preferred).
    • Minimum cement content of 300kg/m3.
    • Use course gravel (10mm size).

    Control Joints

    • Prevent cracking due to movement:
      • Shrinkage or expansion of masonry.
      • Temperature movement.
      • Differential settlement of footings (hogging or sagging).
    • Provided at major changes in height, thickness, door or roof slab openings, T junctions, or using dedicated CJ blocks.

    Gravity Wall System

    • Free draining and easy to construct.
    • Offers design flexibility and cost-effectiveness.
    • Compatible with various soil types.

    ### Fire and Soundproofing

    • Focus on economical and efficient solutions.
    • Complex to meet NCC requirements.
    • Noise resistance failures are more prevalent than fire isolation failures.

    Fire Safety Priorities

    • Life safety: primary focus during fire.
    • Restrict spread: prevent fire from spreading to other buildings or SOUs.
    • Structural stability: prevent collapse to protect occupants and services.

    Selecting Fire & Sound Resistant Systems

    • Define NCC building class and compliance pathway (DTS for floors, walls, ceilings).
    • Understand noise performance requirements.
    • Understand fire performance requirements.
    • Select a system that meets or exceeds both requirements.

    ### Step 1 - NCC Building Class & Compliance

    • Determine NCC building class.
    • Define compliance basis (DTS for floors, walls, ceilings).
    • Determine arrangement of SOUs (compartments).
    • Identify walls/floors requiring fire/noise resistance based on SOU arrangement and proximity.

    ### Step 2 - NCC Noise Requirements

    • Floors should isolate airborne & impact noise transmission.
    • Walls should provide insulation against airborne and impact noise (especially if separating bathrooms, laundries, kitchens from habitable rooms in other SOUs).
    • Avoid compromising noise insulation with service penetrations or doors.
    • Understand noise types and how they are measured.
    • Select a system that meets or exceeds the required noise insulation levels.

    ### Noise Resistance Strategies

    • Mass: adding concrete increases resistance.
    • Isolation: creating a double stud cavity wall.
    • Rigid connection: avoiding rigid connections between opposing floor surfaces.
    • Absorptive material: using mineral wool in walls to absorb sound.
    • Sealing: sealing noise leaks around services, doors, and windows.

    ### Soundproofing: Critical Areas

    • Windows and doors are typically weak spots for sound transmission.
    • Use thick or double glazing for windows.
    • Install acoustic seals between openings and window/door units.
    • Use gaskets around doors and windows.
    • Use solid core doors for better acoustic performance.

    ### Step 3 - Fire Resistance

    • Safety: protect people during a fire.
    • Evacuation: maintain safe escape routes.
    • Structural integrity: prevent collapse.
    • Spread Prevention: restrict fire spread.

    ### Fire Resistance Solutions

    • DTS Solutions: address fire resistance and stability, compartmentalisation, and opening protection.
    • Construction Type: A (highest protection), B (lower protection), C (lowest protection).
    • Resistance Levels: determine the minimum time in minutes that building elements resist fire:
      • Structural adequacy - ability to withstand load
      • Integrity - containment of smoke, flame, and gas
      • Insulation - limiting temperature on the side away from fire
      • Example: 60/60/60 or --/60/--

    Fire Engineering

    • Engineers use software to predict smoke and gas flow.
    • Smoke and gas management: use of sprinklers, smoke screens, smoke doors, and exhaust systems to replace compartmentalisation.
    • Egress routes: keep clear and structurally sound.
    • Compartmentalisation: isolate areas to prevent fire spread.

    Basement Construction

    • Common for parking in multi-unit residential buildings.
    • Typically involves concrete block walls, in-situ concrete columns, and strip and pad footings.
    • The suspended slab (ground floor) provides a structural diaphragm to resist hydrostatic pressure on basement walls.

    Blockwork Detail: Example

    • Reinforced, core-filled concrete blocks.
    • Strip fittings support the walls.
    • Isolation joint separates the infill slab from the main structure.

    Isolation Joint

    • Separates concrete slabs from abutting structures to prevent unwanted restraints.
    • Allows vertical and horizontal movement.
    • Compressible cellular materials are commonly used.

    Basement Walls - Structural Strength and Waterproofing

    • Focus on structural integrity and waterproofing.
    • Hydrostatic pressure from groundwater loads the retaining structure.
    • Water can infiltrate gaps in the wall causing leakage.
    • Not legally required to be waterproof, but recommended.

    Wet Wall Construction

    • Soil is against the wall, requiring a moisture barrier.
    • Separate retaining wall outside the building intercepts hydrostatic load, preventing soil and water from pressing against the building wall.
    • Requires careful waterproofing and sub-soil drainage.
    • Drainage system is necessary to reduce hydrostatic pressure and load.

    Wet Wall Fundamentals

    • Structural adequacy:
      • Hydrostatic pressure.
      • Earth pressure.
      • Superimposed pressure.
    • Relief of hydrostatic pressure: through drainage and water shedding.
    • Impervious waterproofing membrane: provides a barrier against water infiltration. Alternatively, a drainage system can be used.

    ### Approaching Wet Wall Retaining Systems

    • Consider cost, performance, and durability.
    • Select a system based on:
      • NCC performance requirements.
      • Expected water quantity.
      • Water table level and weather variables.
      • Requirements for habitable basements: waterproofing essential.
      • Non-habitable basements: consider NCC and practical considerations.

    ### Site Factors for Wet Walls

    • Rainwater runoff and drainage capacity.
    • Soil drainage capacity (sand vs clay).
    • Depth of basement in relation to the water table (pressure increases with depth).

    Habitable vs Non-Habitable Spaces & Water Resistance

    • Habitable spaces require a higher level of water resistance (NCC 1-4).
    • Non-habitable spaces may have lower requirements, but still require careful design and construction to ensure water resistance.

    Additional Notes

    • Always refer to the NCC and relevant building codes for specific requirements.
    • Seek guidance from qualified engineers and professionals for detailed design and construction.

    Hydrostatic Load Design Considerations

    • Habitable basements below the water table require careful design to manage high hydrostatic loads.
    • Habitable spaces with minor hydrostatic loads should have good drainage to mitigate water pressure.
    • Non-habitable spaces like car parks can tolerate minor hydrostatic loads.
    • Landscaping and other non-building structures can also be designed to withstand minor hydrostatic loads.

    Waterproof Membrane Systems

    • Paint-on liquid membranes are suitable for low-risk basements, balconies, planters, and retaining walls.
    • Self-adhesive sheet membranes offer a convenient installation without heating and are ideal for mid-to-high performance basements, retaining walls, and ramps.
    • Torch-on membrane systems provide high performance for basements, tanking, lift pits, car parks, roofing, landscaped areas, and green roofs.

    Drawing Types

    • Architectural drawings provide detailed design plans.
    • Structural drawings specify the building’s structural elements.
    • Civil drawings outline the site infrastructure.
    • Mechanical drawings detail the building's mechanical systems.
    • Electrical drawings illustrate the electrical systems and wiring.
    • Hydraulic drawings show the plumbing and drainage systems.
    • Landscape drawings depict the design of the outdoor areas.

    Bill of Quantities (BoQ)

    • A BoQ is a list of building components, including quantities and pricing.
    • "Take-off" refers to the process of extracting quantities from drawings.
    • QS (Quantity Surveyors) or estimators typically prepare BoQs.
    • BIM software (Building Information Modeling) can assist in generating quantities and utilizing tools like Buildsoft.

    In Situ Reinforced Concrete Slabs

    • In Situ reinforced concrete slabs are commonly used for floors, offering good noise and fire insulation, thermal performance, strength, span ability, termite resistance, and cost-effectiveness.
    • Downsides include labor-intensive construction, time-consuming formwork, slow construction compared to prefabricated options, and delays in service and cladding installations due to back-propping.

    How Slabs Carry Load

    • Slabs span between walls, with main reinforcement at the bottom for tension.
    • Top steel is primarily for temperature and shrinkage control.
    • Slabs require additional steel at the bottom third to manage tension forces.
    • Continuous spans between multiple supports necessitate extra reinforcement at the top for reverse bending movements.
    • Cantilevered slabs, extending beyond supporting walls, require tension reinforcing at the top to manage bending forces.
    • Slabs supported by columns require extra reinforcing at the column heads to prevent punching shear.

    Reinforcement at Reentrant Corners

    • Thin slabs need additional reinforcement at internal corners to prevent cracking and tearing.

    Joints in Suspended Slabs

    • Expansion joints allow for movement due to temperature changes.
    • Control joints are used to manage and control cracking of concrete.
    • Construction joints are for interrupting pouring processes in large slabs.
    • Joints are rarely needed in small to medium projects.
    • Do not place joints under planted areas or where water can collect.
    • Joints should be visually appealing and functionally sound.

    Dowelled Expansion/Contraction/Construction Joints

    • Allow movement in one direction while maintaining structure.
    • Used to create practical work packages, handle movement in concrete, and allow independent movement while connecting elements (ramps and stairs).
    • Compressible boards form a boundary between poured sections.
    • Steel rebars with deformed lugs bond into the first slab and are embedded (but not bonded) in the second.

    Types of Suspended Slabs

    • Insitu slabs are cast on site using formwork.
    • Precast slabs are prefabricated off-site and assembled.
    • Composite slabs blend precast beams with formwork that becomes part of the construction.

    Economy of Floor Systems

    • Minimizing onsite labor and construction time, along with controlling formwork costs (which can exceed 50% of floor cost), are crucial for economic efficiency.

    Factors Affecting Floor System Economics

    • Site access, crane usage, lead time, construction period, complexity of slab and beam layout, beam types, floor level changes and plant availability all contribute to cost considerations.

    Formwork

    • Formwork is essential for constructing in situ concrete slabs.
    • It typically comprises plywood sheets on bearers and joists, supported by telescopic props.
    • Formwork design should ensure easy stripping and reuse for efficiency.

    Traditional Formwork

    • Suitable for complex layouts and areas where labor cost is lower.

    Engineered Formwork Systems (Table Forms)

    • Offers advantages in terms of speed, simplicity, safety, and lower life cycle costs due to its prefabricated modules and metal frame design.

    Loads on Formwork

    • Formwork must be designed to handle loads from concrete, formwork itself, workers, equipment, placement, spread, compaction, wind, inclined supports, and transport equipment.

    Formwork Operational Issues

    • Maintain tight joints for leak prevention.
    • Keep formwork clean of debris and water.
    • Ensure adequate access for vibrators.
    • Secure conduits and fittings.
    • Install chamfer strips on exposed edges.
    • Adhere to the correct formwork grade.

    Concrete Placement

    • Concrete placement requires careful consideration due to congested reinforcing steel and aggregate size.
    • Excessive vibration can cause aggregate separation.
    • Superplasticizers can improve concrete flow.
    • Curing is essential to ensure strength and prevent cracking.

    Stripping Formwork

    • Early stripping accelerates construction and allows formwork reuse.
    • Stripping should occur only after the concrete can support the load, considering slab span and temperature.
    • Typical minimum stripping times vary depending on the element and its span.

    Back Propping

    • Back-propping is used to support the slab until it can bear its own weight.
    • Enables formwork reuse on higher floors.
    • Slows construction due to restrictions on subsequent work.

    Cavity Masonry

    • Cavity masonry, often used in walls, consists of two layers of masonry separated by a cavity for ventilation.
    • It is not recommended for high-exposure situations or single-story walls without eaves or protection.
    • Failure can occur with high weather exposure, poor detailing, construction errors, and porous materials.

    Brick Composition

    • Brick is a common building material.
    • It offers a variety of colors, textures, and shapes which can be assembled in complex and unique ways.
    • Bricks are produced from different types of clay.
    • Common types of bricks include common bricks, engineering bricks, facing bricks, and special bricks.
    • Bricks can be manufactured using a variety of methods such as the soft mud process, the stiff mud process, and the dry-pressed process.

    Brick Types

    • Clay bricks are fired in a kiln to remove moisture and should be used with expansion joints to prevent cracks.
    • Concrete bricks are manufactured in molds, steam-cured, and vibrated. Larger bricks shrink more slowly and should be considered for larger projects to reduce shrinkage.
    • Calcium Silicate bricks are low-cost, low-strength, and have high porosity.
    • Avoid mixing clay and concrete bricks in the same wall as their different shrinkage and expansion rates will cause problems.

    Sustainability

    • Bricks can be fired in electric kilns, which can reduce carbon emissions if powered by renewable energy.
    • Concrete bricks require large amounts of energy to produce cement.
    • Both clay and concrete bricks have a large embodied energy impact, but can be reused or recycled.

    Damp Proofing

    • Damp proof courses (DPC) prevent moisture from rising through the ground.
    • Most DPCs and flashings in low-cost housing are now made of polyethylene.
    • Alcor, a bitumen-coated aluminum sheet, is more durable than plastic but costs more.
    • DPCs also come in lead, zinc, and copper.

    Cavity Wall Success Criteria

    • For conventional cavity walls, limit exposure to rain.
    • If wind-driven rain is expected (like on a three-story building on a ridge), ensure the cavity is ventilated to allow weep holes to drain.
    • Consider engineered facades for extreme weather exposure.
    • Limit cavity height to one story.
    • Using bricks with low absorption rates will reduce the risk of wall failure.
    • Ensure flashings are correctly installed, high quality, without holes, have lap joints of at least 150mm, and are bonded with the appropriate material.
    • Keep the cavity clean after construction and ensure weep holes drain effectively.
    • Avoid placing pipes or electrical conduits in the cavity.

    Flashing Considerations

    • Critical for preventing water penetration.
    • Fragile, so careful installation is required.
    • Inspect flashings regularly.
    • Absence of weep holes typically indicates no flashing.
    • Short flashings can be allowed to drain into the cavity.
    • Limiting the amount of water in the cavity reduces the risk of failure.

    NCC Performance Requirements

    • Structural performance
    • Acoustic performance
    • Fire performance
    • AS1170 Loading Code defines loads.
    • AS3700 Masonry Structures describes and details brick construction.
    • The standards do not address water resistance, durability, or aesthetic appearance.

    External Walls

    • Consist of two brick skins with an air cavity in between.
    • The outer brick skin is non-load bearing and provides weather resistance, aesthetics, and durability.
    • The inner brick skin is load-bearing and often made of common brick.
    • Outer skins may be face bricks, while inner skins may be re-rendered for a painted finish.
    • Mortar acts as an adhesive to hold bricks together.
    • Wall ties connect the skins, hold them together, and support lateral loads.
    • Air cavities prevent water penetration and provide insulation.
    • Weep holes allow drainage of water from the flashing.
    • Lintels support the load above openings.
    • Cement render adds a consistent layer for a painted finish and improves fire and sound resistance.

    Internal Walls

    • Typically a single skin of brickwork with render or plasterboard lining.
    • Internal walls can be load-bearing or non-load-bearing, based on structural design.

    Brick Properties

    • Durability:
      • Exposure (for severe marine environments)
      • GP (for other areas and internal use)
    • Initial Rate of Absorption:
      • How quickly water is absorbed from mortar.
      • Adjust mortar to suit the brick type.
    • Expansion:
      • Can expand up to 2mm per meter ("E" factor).
      • Most expansion occurs within two weeks of firing, so allow for this to minimize problems.

    Mortar Considerations

    • Cement: GP or GB (GB includes fly ash)
    • Sand: Free of organic matter and low clay content (beach sand is unsuitable)
    • Water: Clean and fresh (potable)
    • Additives: Use only with manufacturers' specifications.
    • Lime: Improves mortar quality but slightly reduces strength.

    Mortar Grading and Batching

    • Different grades for different applications:
      • M4 (strongest): C1: L.05: S4.5
      • M3 (most common for external/internal load-bearing walls): C1: L1: S6
      • M2 (internal non-load-bearing walls): C1: L1: S9
      • M1 (restoration work): C0: L1: S3

    Wall Ties

    • Transfer lateral load from the outer wall to the supporting structure.
    • Designed to handle both tension and compression forces.
    • Prevent water transfer across the cavity with a drip groove or drip line.
    • Three classes: Light, medium, heavy.
    • Five durability classes (R1-R5, R5 being most durable), typically 316 grade stainless steel.
    • Usually placed at 600mm centers.
    • At the top, sides, and openings, place at 300mm centers.
    • Embed 50mm into mortar.

    Damp Proof Courses (DPCs)

    • Prevent water from rising up the wall.
    • Stop dissolved salt attack from ascending.
    • May be combined with flashing.
    • Install up to 150mm above finished grade.
    • Must protrude slightly from the wall to prevent moisture passage.

    Flashings

    • Prevent water penetration around doors, windows, chimneys, and abutting roofs.
    • Drain water from the cavity to the outer wall.
    • Comply with AS2904 standards.

    Expansion/Control Joints

    • Bricks grow and contract due to temperature variations.
    • These movements can damage long or tall walls.
    • Joints are implemented to prevent or control cracking and structural issues.
    • Occur at windows, doors, and other areas where movement is anticipated.

    Slip Joints

    • Used where brick walls support concrete slabs.
    • Provide vertical support but allow horizontal movement between dissimilar materials.
    • Consist of two sheets of thin metal with graphite dust or grease.

    Materials on Site

    • Do not use broken or misshapen bricks.

    Bond and Gauge

    • Design brick wall length and height to maintain a consistent pattern and minimize cutting.
    • Bond refers to the overlapping pattern in brickwork.
    • Wall height is governed by brick gauge, which is the incremental increase in height with each course of bricks.
    • Stretcher bond is the most common type.

    Scaffolding

    • Used to make bricklaying easier and safer.
    • Add cost and time to the project, so use sparingly.

    Articulation

    • Divides walls into separate panels to allow for independent movement, focusing movement at joints.
    • Joints are often positioned at windows, doors, and behind downpipes.

    Mass Timber

    • Wood's strength depends on the glue used.
    • Casein glue is a milk byproduct.
    • Epoxy glue has been available since 1967.
    • Timber is susceptible to moisture, thermal movement, biological attack, and infestation.

    Objectives of Using Timber

    • Increased prefabrication, which can improve construction costs and deliver certainty.
    • Reduced resource usage, including labor.
    • Improved site safety.
    • Renewable resource with low embodied energy in the conversion process.

    Cross-Laminated Timber (CLT)

    • Solid, large timber panels made from wide planks glued together in transverse layers.
    • A screed of gypsum or polymer modified concrete is often used over CLT floors to improve acoustics and fire performance.

    CLT Pros

    • Reduced construction time.
    • High potential for off-site construction.
    • Faster installation and follow-on trades.
    • Lightweight structures.
    • Deconstructable.

    CLT Cons

    • Limited Australian manufacturers.
    • Crane-dependent.
    • Softwood only.
    • Cannot be exposed to the exterior (requires cladding).
    • Requires treatment for high-hazard areas.

    Roof and Balcony Waterproofing

    • NCC requires preventing water penetration to avoid health hazards, dampness, and property damage.
    • Waterproofing is a high-risk item: Poor workmanship, small leak holes, costly to rectify, and difficult to diagnose problems.

    Balconies and Flat Roofs

    • Small slope (1:60) for drainage to outlets.
    • Two-way fall is common.
    • Drain points direct water to stormwater systems.
    • Downpipes are often concealed in ducts or mounted externally.
    • Parapet walls on roofs or hobs on balconies create a "swimming pool" effect.
    • Penetrations through waterproofing from plumbing, air conditioning, and balustrading increase risk.

    Fitness for Purpose Requirements

    • Must be compatible with other materials in contact.
    • Must withstand UV exposure.
    • Must accommodate differential movement.
    • Must withstand environmental conditions.
    • Must have an expected lifespan to match overlays.

    Proper Installation

    • Membrane should be applied to the substrate, not the tiling screen.
    • Ensure falls to drainage points or free edges.
    • Avoid ponding of water on the membrane.
    • May include membrane types, separation layers, sound reduction layers, and protection from UV, mechanical damage, and movement.

    Drained Cavity with Sheet Membrane System

    • Flat surface.
    • No visible drains.
    • Higher fall is possible without impacting usability.
    • No step at doors.
    • Serviceable membrane.

    Falls

    • Prevent ponding and direct water to outlets.
    • Overall height influences finished floor levels.

    Substrates

    • In-situ concrete: The most common substrate and easiest to achieve two-way falls.
    • Precast: Requires a topping slab for falls.
    • Timber: Often used floor in townhouses but not in wet areas.
    • Consider finished floor height differences between interior and exterior.
    • Consider movement requirements between substrate and membrane.

    Issues With Achieving Falls

    • Tile size: Large tiles make achieving two-way falls difficult, especially near drains.
    • Tile screen/bed thickness: May impact floor height differences and reinforcement requirements.

    Exposure Categories

    • Exposed:
      • Greater than 3 stories or 9m above ground.
      • Exposed to extreme weather.
      • Facing flat terrain or water.
    • Sheltered:
      • Less than 9m or shielded from direct wind.
      • Contains shelter structures from rain and wind.

    Waterproofing Recommendations for Exposed Areas

    • Shrouds over weep holes to deflect high wind pressure.
    • Cross-cavity flashing should extend further up the cavity than usual.

    Efflorescence

    • Calcium crystal or soluble salt buildup that disfigures concrete/tile surfaces.
    • Caused by water saturation of the mortar tile bed.
    • Minimized with falls into the substrate before membrane and screeds are applied.
    • Prevent water ingress by properly grouting and reinstating the membrane or using a water-resistant tile bed.

    Membrane Protection

    • Essential to prevent damage to the waterproofing system.
    • Permanent protection options: Drainage cells, building plastic, tiles, and rubber or cork mats.

    Membrane Types

    • Fully Bonded to Substrate:
      • Liquid membranes that adhere to the substrate.
      • Sheet membranes with primer, peel and stick, or heat melting.
    • Partially Bonded/Mechanically Fixed:
      • Sheet membranes with welded laps, terminations, or penetrations.
      • Can remain unattached horizontally, but fixed vertically.
      • Secured with mechanical fasteners or spot-bonded bitumen.
    • Unbonded:
      • Similar to partially bonded, but typically held down with ballast to resist uplift.

    Membrane Failure Causes

    • Movement at joints.
    • Differential movement between materials.
    • Floor deflection during or after installation.
    • Shrinkage.
    • Temperature and moisture variations.

    Membrane Classification

    • Class 1: Low extensibility (usually liquid membranes).
    • Class 2: Medium extensibility.
    • Class 3: High extensibility.

    Membrane Flexibility

    • Reinforcing fabric alters membrane characteristics.
    • More rigidity requires extra attention at junctions and joints.
    • Carefully choose a bond breaker at wall/floor junctions.

    Terminating the Membrane

    • At hobs, upturns, downturns, or terminations:
      • Seal or cap the leading edge.
      • Protect moisture ingress.
      • Support the membrane.
      • Direct moisture flow.

    Capping at Termination Points

    • Typically preformed metal flashing that overlaps the membrane.

    Termination at Penetrations

    • Seal and cap the membrane around penetrations (plumbing, air conditioning, and balustrading).

    Surface Layers/Finishes

    • Concrete topping screed.
    • Tiles or stone on sand cement screed.
    • Pavers on stabilized sand.
    • Pavers on support pads.
    • Timber decking on battens.

    Pedestal System

    • Water drains between tile gaps.

    Balustrading

    • Balustrades must meet safety requirements.
    • Consider wind loads, material strength, and corrosion resistance.

    Alternatives to Waterproofing

    • Chemical additives to concrete mix improve waterproofing properties.

    Square Meters and Floor Area

    • Usable Floor Area (UFA)
    • Net Lettable Floor Area (NLA)
    • Gross Floor Area (GFA): Typically 1.2 to 2 times the usable floor area, including service spaces.

    Typical Internal Stairs

    • Floor to floor height: Approximately 3.1m.
    • Rise: 3100 / 17.2 = 18 risers.
    • Goings: 17 x 280 = 4.8m.
    • Area: 1m x 4.8m = 5sq m.

    Stair Ergonomics

    • Slope: 2R + G = 540 - 700.
    • Regularity of risers and goings.
    • Non-slip surfaces.
    • Landings to prevent falls.
    • Dog-leg stairs are safer than continuous stairs.

    Stair Materials

    • Reinforced or pre-stressed concrete.
    • Steel: Not less than 6mm thick.
    • Timber: Not less than 44mm and not glued.

    NCC Stair Requirements

    • No more than 18 risers and not less than 2 risers in any flight.
    • No gap to fit a 125mm sphere between risers or balustrade.

    Stairs and Fire Egress Considerations

    • Fire doors onto stairways must meet FRL standards and be self-closing.
    • Sufficient exits to open spaces from dwellings.
    • Stair width must accommodate egress of the building's population.

    Stair Design

    • Minimum balustrade height: 1000mm minimum for flat areas and 865mm from the nosing of the stair tread.
    • Minimum baluster spacing: 125mm sphere clearance.
    • Minimum landing areas: 750mm from door to stair.

    Stair Definitions

    • Going: Horizontal dimension of a tread, excluding overhang from the tread above.
    • Landing: Area at the top, bottom, or between flights.
    • Riser: Height between consecutive treads.
    • Tapered Tread: A stair tread with a walking area that narrows progressively towards one end.

    Stair Material Comparison

    • Concrete: Generally the best fire rating, stronger, and more durable and less noisy than timber.

    Render Finishes

    • Typically applied over masonry/concrete.
    • Benefits:
      • Creates a smooth, flat surface.
      • Improves water resistance.
      • Provides a decorative finish.
      • Can improve sound rating.
      • Requires quality control.
      • Labor-intensive and requires scaffolding.
      • Prone to cracking if poorly installed.

    Render Requirements

    • Render mix must be suitable for the substrate.

    Render Materials

    • Cement
    • Lime: Reduces cracking.
    • Sand: Coarse for undercoats, finer for finishing coats.
    • Water
    • Admixtures: Plasticizers

    Substrate Preparation

    • Remove loose materials, dirt, grease, and debris.
    • Prepare a keyed surface.
    • Dampen the wall to prevent moisture absorption.

    Render Coats

    • Usually one or two coats:
      • Based on substrate condition, weather exposure, desired finish.
      • Allow 3 days drying time between coats.

    Types of Render Coats

    • Dash: Flicked or splattered for a rough finish.
    • Undercoat/Scratch Coat: 10-15mm thick. This is the semi-dry coat that is raked or scratched to provide a key for the next coat.
    • Final Coat: Cement render applied with a trowel over the undercoat.
    • Set Coat:
      • Less common.
      • 3mm hard plaster troweled on the finish.
      • Can be applied as the final coat over cement render or directly to a concrete slab.
      • Offers a higher quality finish.

    Alternative Render Materials

    • Acrylic render: More common, thinner coat thickness, greater flexibility, preferred for flat surfaces.

    High Build Acrylic Finishes

    • Thick, flexible, semi-smooth paint.
    • Trowel-on option offers fine to medium sand finish.
    • Provides long-term maintenance and protection.
    • Suitable for tall, hard-to-access buildings.

    Decorative Finishes

    • Wood Float: A smooth, dense finish achieved by skimming the final coat with a wood float.
    • Bagged Finish: Rubbing damp hessian cloth into the surface.
    • Sponge Finish: Using a damp sponge to mop or sponge the unhardened surface.

    Control Joints

    • Cement render cracks due to shrinkage and movement.
    • Joints are implemented to control cracking and minimize structural issues.

    Metal Lath

    • Used on areas of weakness to reinforce render and prevent substrate movement and cracking.

    Curing

    • Prevent render from drying too quickly (can cause shrinkage and prevent full hydration).
    • Keep all coats damp for three days or until the next coat is applied.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Construction Technology 2 Lecture Notes PDF

    More Like This

    Untitled Quiz
    6 questions

    Untitled Quiz

    AdoredHealing avatar
    AdoredHealing
    Untitled Quiz
    37 questions

    Untitled Quiz

    WellReceivedSquirrel7948 avatar
    WellReceivedSquirrel7948
    Untitled Quiz
    55 questions

    Untitled Quiz

    StatuesquePrimrose avatar
    StatuesquePrimrose
    Untitled Quiz
    50 questions

    Untitled Quiz

    JoyousSulfur avatar
    JoyousSulfur
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser