The Ultimate Guide to Plasterboard: A Complete Introduction for Builders and Apprentices

Introduction

Plasterboard is the backbone of modern interior construction in Australia. Whether it's a high-rise apartment in Perth, a suburban renovation in Adelaide, or a new build in a regional town, chances are you're surrounded by plasterboard — covering your walls and ceilings, forming fire-rated systems, buffering sound, or even resisting moisture in your bathroom.

But while the end result often looks simple, the process of working with plasterboard is anything but. Behind every clean join and flawless ceiling is a deep understanding of framing, fixing, finishing, and compliance. And for new apprentices or anyone entering the industry, learning how to properly select, install, and finish plasterboard is one of the first and most important steps in becoming a skilled tradesperson.

This guide is designed to give you a complete, ground-up understanding of plasterboard systems. We’ll break it down by components, techniques, and use cases — just like you’d learn in your first year on site.

Whether you’re a first-year apprentice starting your journey, a builder brushing up on system standards, a DIY renovator seeking clarity or a business training up new staff

This guide will walk you through everything you need to know — from how framing works, to what compound goes where, and how to avoid mistakes that can cost you later down the line.

Let’s start from the beginning: What exactly is plasterboard?

 

Chapter 1: What Is Plasterboard?

Plasterboard, also known as drywall or gypsum board, is a panel made of a gypsum core encased in a paper liner. It's designed for internal wall and ceiling linings and is one of the most widely used building materials in modern construction. Lightweight, cost-effective, and easy to cut and fix, plasterboard creates smooth, paint-ready surfaces and can be adapted to meet a range of building requirements.

What’s Inside?

The core of plasterboard is made from gypsum — a naturally occurring mineral (calcium sulfate dihydrate). This core is sandwiched between two layers of heavy-duty paper. Depending on the board type, additives may be included to improve fire resistance, moisture resistance, soundproofing, or impact performance.

Why Is It So Common?

• It’s fast and easy to install
• It provides a smooth, even surface for painting or wallpapering
• It can be cut to size with basic hand tools
• It’s adaptable — different types suit different rooms and conditions
• It’s widely available and cost-effective

Where Is It Used?

• Residential homes — internal walls, ceilings, garage linings
• Multi-residential and commercial — fire and acoustic wall systems
• Wet areas — with water-resistant plasterboard (WR board)
• High-traffic areas — with impact-resistant boards

Australian Standards and Compliance

All plasterboard used in Australian construction must comply with AS/NZS 2588: Gypsum Plasterboard. This standard covers the dimensions, performance characteristics, and minimum requirements for safety and installation.

Brands We Recommend

At Online Plasterboard Supplies, we proudly supply Siniat plasterboard — one of Australia's most trusted and widely used brands in residential, commercial, and specialist systems.

Chapter 2: Types of Plasterboard and Their Applications

Not all plasterboard is the same. In fact, choosing the wrong type of board for a job is one of the most common mistakes apprentices and DIYers make. Depending on the room, the environment, and the performance requirements, there’s a specific type of plasterboard designed to meet that need.

1. Standard Plasterboard

This is the most commonly used board in residential construction. Suitable for dry, low-impact internal spaces like living rooms, bedrooms, hallways, and studies. It’s lightweight, easy to work with, and available in 10mm and 13mm thicknesses.

2. Fire-Rated Plasterboard

Also known as FR board, fire-rated plasterboard is reinforced with glass fibres and special additives to slow the spread of fire. Used in intertenancy walls, garage walls, stairwells, and in any system requiring an FRL (Fire Resistance Level) rating.

Example: Siniat 13mm Fireshield

3. Acoustic Plasterboard

Designed to reduce sound transmission between rooms, acoustic plasterboard is denser than standard board and ideal for media rooms, bedrooms in multi-res builds, and offices.

Example: Siniat 10mm Soundshield

4. Moisture-Resistant Plasterboard

Also known as Wet Area or WR board. Treated with a water-repellent core and paper facing, it's designed for bathrooms, laundries, and kitchens. It must be used in combination with proper waterproofing membranes as per NCC requirements.

5. Impact-Resistant Plasterboard

High-density board with added durability. Used in high-traffic areas like schools, hospitals, and apartment corridors where knocks and bumps are expected.

6. Ceiling-Grade Plasterboard

Lighter boards designed for overhead use. Reduced sag properties and often installed with a plasterboard lifter to minimise strain during install. Commonly 10mm thickness with tighter screw spacing requirements.

7. Specialty Boards

• Curved Board: For creating arches and features
• Perforated Acoustic Board: For ceilings in theatres and auditoriums
• Foil-Backed Board: Used for insulation and vapour control

Choosing the Right Board

The board you use affects the longevity, safety, and quality of the finished room. Always check the room requirements — and when in doubt, ask your supplier or refer to the manufacturer’s installation guide.

Shop Trusted Options

Browse our full range of Siniat plasterboard products for every room type and compliance requirement.

Chapter 3: Framing 101 — Studs, Joists, Noggings and Spacing

Before you hang a single sheet of plasterboard, you need a well-prepared frame. The frame — made from either timber or steel — supports the board and determines how strong, level, and compliant your walls and ceilings will be.

Wall Framing Components

• Studs: Vertical framing members, typically spaced at 450mm or 600mm centres (measured from centre to centre).
• Noggings: Horizontal bracing pieces installed between studs. They provide rigidity and help prevent twisting or bowing of the studs.
• Top and Bottom Plates: Horizontal framing at the top and bottom of the wall. The studs are fixed between these plates.
• Junction Studs: Used at internal corners or where two walls meet. These provide fixing points for board edges and ensure a clean, rigid join.

Ceiling Framing Components

• Joists: Horizontal framing members supporting ceiling sheets. Like studs, they’re spaced at 450mm or 600mm centres.
• Trimmers: Used to frame around ceiling features like skylights or bulkheads.
• Battens: Sometimes used under joists to provide fixing points and level adjustment.

Framing Materials

• Timber Framing: Traditional and common in residential work. Use seasoned pine or equivalent to prevent warping.
• Steel Stud Framing: Often used in commercial or multi-residential jobs. It’s non-combustible, lightweight, and dimensionally stable.

Spacing Guidelines

Spacing of studs and joists affects sheet performance. Always follow the manufacturer’s recommendations:

• Standard wall sheets: 600mm centres
• Ceilings: 450mm centres are recommended for reduced sag
• Heavy boards (fire or acoustic): 450mm or closer spacing may be required

Level and Square Frame = Smooth Finish

Before you even think about putting up plasterboard, always check framing for straightness and level. Use a long straight edge (or laser level), and pack or plane where needed. A few millimetres out of alignment now can result in bowed sheets or cracked joints later.

Fixing Considerations

All edges of the board must land on framing. That means joints should align with studs or joists. Use noggings or additional support if sheets don’t naturally align.

In the next chapter, we’ll explore how junction studs and trimmers work — and why they matter so much for board performance and finish quality.

Chapter 4: Understanding Junction Studs and Trimmers

When two walls meet or when plasterboard needs support around openings like doors or windows, standard studs aren't enough. This is where junction studs and trimmers come in — crucial framing components that support board edges, prevent cracking, and ensure smooth, strong joins.

What Is a Junction Stud?

A junction stud is an additional vertical stud installed at internal or external corners where two wall frames meet. It provides a solid fixing point for adjoining plasterboard sheets and ensures both boards have sufficient backing for fasteners and jointing.

Common Configurations:

• Back-to-back studs: Two studs nailed or screwed together to form a wide fixing face
• L-shaped or boxed studs: Using offcuts or noggings to create corner support when space is tight
• Three-stud corner: Used when both sides of the corner will be sheeted and finished

Without a proper junction stud, plasterboard joins may end up unsupported — leading to movement, cracking, and eventual rework.

What Is a Trimmer?

Trimmers are short horizontal or vertical frame members used to form openings for windows, doors, or ceiling features like skylights. They help transfer loads to surrounding studs and provide support for sheeting around cutouts.

Where You’ll Use Trimmers:

• Above and below windows
• Beside and above door frames
• Around skylights or ceiling penetrations

Like junction studs, trimmers must be installed flush and level to avoid bowing the plasterboard. They must also be fixed securely to maintain structural integrity and to ensure compliance with AS 1684 or NCC framing requirements.

Pro Tips:

• Always install additional studs or trimmers wherever sheet joints will fall off the main frame.
• Pre-plan your board layout — it will help you position junction studs and trimmers in advance.
• Use blocking or bridging timber if needed to support wide gaps or offsets in framing.

Next up: we'll explore the fasteners, adhesives, and fixings that bring the whole system together — and how to use them correctly.

Chapter 5: Fixings — Screws, Nails and Adhesives

Plasterboard must be fixed securely to its frame — and the way you do that depends on the board type, frame material, and whether you’re working on a wall or ceiling. This chapter breaks down the correct use of screws, nails, and adhesives, and when each is appropriate.

1. Screws

Drywall screws are the preferred fixing method in most modern builds — especially for steel frames and ceilings. They provide superior holding power and reduce the chance of nail popping or movement over time.

Common Types:

• Type W: Coarse thread, used for fixing to timber framing
• Type S: Fine thread, used for fixing to steel studs (0.55–0.75mm)
• Type S-DS: Drill point screws for thicker steel (up to 1.2mm)

Best practice: Screws should be installed 10–16mm from sheet edges, spaced 200mm apart for ceilings and 300mm for walls unless otherwise specified. Use a drill with a depth stop to avoid overdriving and breaking the board face.

2. Nails

Ring shank nails or clouts were commonly used before screws became standard. While still used in some timber-framed walls, they’re generally not recommended for ceilings or high-performance systems due to potential for movement.

Typical Nail:

• 30–40mm ring shank nails for timber frames

Nails should be driven flush — not punched below the surface — to avoid damage. If used in ceilings, back-blocking is highly recommended to prevent sagging.

3. Adhesives

Stud adhesives are used in combination with mechanical fixings to improve bond strength and reduce screw/nail reliance. This is especially important in ceiling installations where vibration and gravity can work against fixings.

Apply walnut-sized daubs of Siniat acrylic stud adhesive along studs or joists — typically 200–300mm apart and never closer than 200mm from sheet ends. Do not apply adhesive where screws will go.

Quick Fixing Reference

Frame Type	Fixing Type	Recommended Use
Timber	Type W screws or ring shank nails + adhesive	Walls & ceilings
Steel (up to 0.75mm)	Type S screws	Residential walls & ceilings
Steel (1.2mm+)	Type S-DS self-drilling screws	Commercial framing

Key Fixing Rules

• Always ensure each board edge lands on framing for full support
• Back-block ceiling joins where needed
• Use control joints or expansion joints as per system specs
• Follow screw spacing and edge distance requirements strictly

Up next, we’ll cover how to safely cut, lift, and handle plasterboard on site — and the most efficient ways to work cleanly and accurately.

Chapter 6: Cutting and Handling Plasterboard

Plasterboard is designed to be lightweight and easy to work with, but incorrect handling or cutting can lead to breakage, wasted material, and uneven finishes. In this chapter, we cover how to cut, lift, and store plasterboard correctly — whether you're working solo or as part of a crew.

Tools You'll Need

• Utility knife (sharp blade is essential)
• T-square or straight edge
• Measuring tape and pencil
• Keyhole or jab saw (for cutting holes and shapes)
• Sandpaper or sanding block (for smoothing edges)

Step-by-Step: Cutting Plasterboard

1. Measure the required dimensions and mark with a pencil.
2. Score the front face of the board (paper side) with your utility knife along a straight edge.
3. Snap the board back away from the scored line — it should break cleanly.
4. Cut through the back paper layer from behind to fully separate the two pieces.
5. Lightly sand any rough edges before installation.

Cutting Around Fixtures and Openings

To cut out holes for power points, light fittings, or pipe penetrations, use a jab saw or hole saw after the sheet is fixed loosely or while flat on trestles. Mark from behind or trace directly onto the sheet for accuracy.

Handling and Lifting

Plasterboard is brittle if not supported evenly — especially in longer lengths like 3600mm sheets. Always carry sheets vertically and with two people if possible. Use a plasterboard lifter for ceilings or large boards to prevent strain or injury.

Key Tips:

• Never drag sheets — lift them from both ends
• Store flat on dunnage off the ground to avoid moisture damage
• Avoid stacking more than 300mm high on site unless secured

Edge Types

• Recessed Edge: Factory edge designed for joint tape and compound
• Square Edge: Common on cut edges — requires careful finishing

Safe Work Practices

• Wear gloves and long sleeves to avoid paper cuts
• Use a dust mask when cutting or sanding
• Keep cutting surfaces clean and stable

Once your sheets are accurately cut and safely staged, you’re ready to begin fixing them to walls and ceilings — which we’ll explore next.

Chapter 7: Installing Plasterboard on Walls

Wall linings form the majority of plasterboard applications on any job site. Proper installation is key to achieving a smooth, long-lasting finish. In this chapter, we cover step-by-step instructions for installing plasterboard on framed internal walls.

Wall Prep Checklist

• Frame spacing checked — ideally 450mm or 600mm centres
• Studs straight and plumb
• Noggings installed at required heights (especially mid-height for 2.7m+ sheets)
• Power and plumbing installed and protected
• All surfaces dry and free from dust or grease

Recommended Installation Order

Always install ceilings before walls. This allows wall sheets to butt cleanly up to the ceiling, hiding any ceiling board movement or edges behind the cornice or shadow line.

Fixing Method

• Use adhesive and screw/nail combination for timber frames
• Use screws only for steel frames
• Apply adhesive daubs every 300mm, 200mm in from sheet ends
• Fix edges of the sheet with screws 10–16mm from the edge
• Vertical joints should fall over a stud — never unsupported

Sheet Orientation

• Horizontal (most common): Reduces the number of joints, especially in standard 2400mm high walls
• Vertical: Used in taller walls or commercial projects

Joint Positioning Tips

• Stagger joints between rows
• Try to avoid four-way joints — use offcuts or adjust layout to overlap joins
• Where butt joints are necessary, back-blocking is recommended for ceilings and wide wall spans

Door and Window Openings

Wherever plasterboard wraps around doors or windows, use additional noggings or trimmers to support the edges. Cut sheets accurately and avoid having joints meet at the top corners of openings — this reduces cracking risk.

Finishing Up

• Check for flush joins and tight sheet fit
• Pre-fill any wide gaps (over 5mm) with compound before taping
• Ensure all screw heads are slightly recessed but not broken through

Once wall sheets are installed and fixed, you’re ready to move into the ceiling process — which has its own key differences and considerations covered next.

Chapter 8: Installing Plasterboard on Ceilings

Ceiling installation is often one of the most physically demanding parts of plasterboard work — and it’s also where mistakes are most noticeable. A sagging or cracked ceiling can ruin the look of an entire room. That’s why understanding correct fixing, adhesive use, and joint layout is critical.

Ceiling-Specific Considerations

• Ceiling joist spacing should be no more than 600mm (450mm recommended for heavy or sag-resistant boards)
• Use ceiling-grade plasterboard (typically 10mm thick, with high sag resistance)
• Back-blocking is recommended for ceilings with three or more recessed joints or butt joints between joists

Installation Order

Always install the ceiling before the walls to ensure better joint concealment and to allow for proper cornice or square set finishing.

Tools and Setup

• Plasterboard lifter: Strongly recommended for solo or two-person jobs
• Adhesive: Apply daubs to every joist (200–230mm apart, avoid screw zones)
• Screws: Type W (timber) or Type S (steel) — placed 200mm apart on all joists

Fixing Method

1. Apply adhesive daubs to joists, starting 200mm from each end of the sheet
2. Lift the sheet into position (perpendicular to joists) and press it firmly into the adhesive
3. Fix edges first, then work toward the centre. Avoid screwing through adhesive daubs
4. Use two fixings per joist along recessed joins, and one fixing at centre joists

Joint Layout

• Stagger all recessed joints to reduce stress and prevent cracking
• Avoid butt joints where possible; if necessary, use back-blocking behind the joint
• Ensure at least one truss/joist separates parallel recessed joints

Back-Blocking (Highly Recommended)

Back-blocking involves gluing narrow strips of plasterboard (called back-blocks) behind recessed joints to reinforce them and reduce the risk of cracking. Especially useful for long ceiling spans or where humidity and movement are expected.

Pro Tips

• Always use a straight edge or laser level to check alignment before fixing
• Use sag-resistant board for spans over 450mm
• Ensure adequate ventilation in ceilings to reduce moisture build-up

With ceiling boards fixed correctly, you’re ready to begin jointing and finishing — the next step in delivering a seamless, paint-ready result.

Chapter 9: Jointing and Finishing Systems

Jointing plasterboard is a critical step in achieving a smooth, durable finish. The process involves covering recessed or square edges with tape and compound, blending them into the surrounding surface. Done correctly, joints become invisible after painting — done poorly, they crack, bubble, or show through.

Three Coat Jointing System

Australian standard jointing involves three layers:

1. Base coat: To embed the joint tape and build the first layer
2. Second coat: To widen the feathered edge and build up the joint
3. Final coat: To fully feather the joint for a flat, seamless finish

Each coat must fully dry before applying the next. Drying times vary with climate and humidity, but 24 hours is a common benchmark.

Jointing Tools

• Broadknives — usually 150mm, 200mm and 300mm sizes
• Jointing pan or hawk
• Sanding pole or sanding block
• Dust mask (always wear during sanding)

Tape Types

• Paper tape: Strongest option, used in most professional applications. Must be embedded into compound
• Mesh tape: Easier to use for beginners, but can lead to cracking if not properly coated

Compounds

• Siniat all-purpose compound — suitable for all three coats
• Base coat compounds — usually heavier-bodied and stronger
• Top coat compounds — lighter and easier to sand for finishing

Internal Corners

Use pre-creased paper tape and run your broadknife along each side to embed it into a layer of base compound. Smooth one side first, then return and smooth the other side to avoid pulling the tape.

External Corners

Fix metal corner beads before jointing. Apply compound on both sides, feather out with wider knives on second and third coats. Some corner trims come pre-finished and only require top coating.

Sanding and Finishing

• Allow joints to fully dry before sanding
• Use a light to check for unevenness or ridges
• Sand with 180–220 grit, avoiding damage to surrounding paper
• Wipe down with a dry cloth before priming or painting

Correct jointing is essential to avoid call-backs, especially in ceiling joins, over door frames, and in wet areas. In the next chapter, we’ll cover how to handle control joints and back-blocking for large or high-movement surfaces.

Chapter 10: Control Joints and Back-Blocking

As buildings move and settle, plasterboard can crack — especially in large ceilings, long corridors, and areas exposed to temperature or humidity changes. Control joints and back-blocking are two key techniques used to prevent visible defects over time and ensure long-term durability.

What Is a Control Joint?

A control joint is a deliberate break in the plasterboard lining that allows for movement. It’s usually filled with a flexible sealant or a specialised control joint bead. Control joints help absorb building movement and reduce stress on the board.

When Are Control Joints Required?

• Where ceiling or wall lengths exceed 12 metres (or 6 metres for suspended ceilings)
• At changes in building materials (e.g., timber to steel transitions)
• Over structural control joints in the substrate
• In corridors or large open-plan rooms with long expanses of board

How to Install a Control Joint

Control joints are created using proprietary joint beads or flexible backing systems. These are installed at framing junctions with a small gap between plasterboard edges (typically 6–10mm). A bead or sealant is applied over the gap, allowing slight movement without cracking.

What Is Back-Blocking?

Back-blocking is a method of reinforcing sheet joins — especially recessed joints in ceilings — using narrow strips of plasterboard glued behind the joint to prevent cracking and sag.

When to Use Back-Blocking:

• Ceilings with more than two recessed joints
• Butt joints between ceiling sheets that fall between framing members
• In high-humidity environments or long-span ceilings

Back-Blocking Step-by-Step

1. Cut 200mm wide strips of plasterboard (offcuts work great)
2. Apply stud adhesive across the strip and fix behind recessed joints on the rear of the ceiling sheets
3. Fix sheets in place and allow adhesive to dry before jointing

Tips for Preventing Cracks in Large Areas

• Use control joints as per manufacturer guidelines
• Always install back-blocks in large or suspended ceilings
• Avoid rigid fixing over known structural joints — use flexible sealants instead
• Ensure framing is level and not over-spanned

Next, we’ll cover wet area installation — including compliance rules, moisture-resistant board, and waterproofing tips to meet the NCC and AS 3740.

Chapter 11: Wet Areas — Compliance, Waterproofing, and WR Board

Wet areas such as bathrooms, laundries, toilets, and kitchens require special treatment to prevent water damage, mould growth, and structural issues. In Australia, these areas are governed by strict standards to ensure long-term protection. This chapter covers what you need to know about wet area plasterboard and compliance requirements.

What Is a Wet Area?

Under the National Construction Code (NCC), a wet area is defined as any room subject to water splash, steam, or excessive moisture. This includes:

• Showers and bathrooms
• Laundries
• Toilets with hand basins
• Kitchens (behind sinks and dishwashers)

Wet Area Plasterboard (WR Board)

Moisture-resistant plasterboard, often referred to as WR board or Wet Area board, is designed with a water-repellent core and mould-resistant facing paper. It is green in colour and must be used in wet zones prior to waterproofing and tiling.

Key Features:

• Complies with AS/NZS 2588 for moisture resistance
• Suitable for bathrooms, laundries, and splash zones
• Not a substitute for waterproofing membranes

Waterproofing Requirements

WR board must always be used in conjunction with a waterproofing system, as per AS 3740 – Waterproofing of Domestic Wet Areas.

Minimum Requirements Include:

• Waterproof membrane applied to all shower recesses and floors
• Upstands (walls) waterproofed to 1800mm in showers
• Wall-to-floor junctions waterproofed to at least 150mm
• Full waterproofing behind baths and laundry tubs if adjacent to walls

Installation Tips for Wet Area Plasterboard

• Use moisture-resistant screws and compatible adhesives
• Allow gaps at floor level for movement (typically 10mm)
• Do not use standard jointing compounds — use WR-compatible versions if joints fall in wet zones
• Use corrosion-resistant corner beads or trims

Compliance and Inspection

Most states and councils require wet areas to be certified by a licensed waterproofer. Ensure all WR board installations are documented and compliant before membranes and tiling begin.

To shop compliant WR board for your bathroom or laundry, check our range of moisture-resistant plasterboard.

Next up: we’ll explore fire-rated systems and where they're required in residential and commercial construction.

Chapter 12: Fire-Rated Systems

Fire-rated plasterboard systems are essential for protecting occupants and slowing the spread of fire in residential and commercial buildings. These systems are required by the NCC in specific locations where fire resistance is critical — such as between dwellings, around garages, and along exit paths.

What Is Fire-Rated Plasterboard?

Fire-rated plasterboard (also called FR board) contains a specially formulated gypsum core reinforced with glass fibres and other additives that improve its fire resistance. When installed as part of a certified system, it can achieve a Fire Resistance Level (FRL) rating to meet code requirements.

Common Product:

Siniat 13mm Fireshield — used in intertenancy walls, service risers, and commercial partitions.

Where Fire-Rated Systems Are Required

• Intertenancy walls (Class 1a townhouses, Class 2 apartments)
• Walls between dwellings and garages
• Service shafts and risers in commercial buildings
• Exit corridors and fire-isolated stairwells
• Ceilings below habitable spaces (e.g., over car parks)

What Is an FRL?

An FRL (Fire Resistance Level) is a performance rating that indicates how long a building element can withstand fire. It’s expressed in minutes and covers:

• Structural Adequacy — the ability to carry load
• Integrity — the ability to resist flames
• Insulation — the ability to resist heat transfer

For example, an FRL of 60/60/60 means the system maintains all three criteria for 60 minutes.

System Installation Rules

Fire-rated systems must be installed exactly as tested by the manufacturer. This includes:

• Correct number of board layers and thickness
• Specified framing and fixing methods
• Approved fire sealants around penetrations
• Use of fire-rated insulation if required
• Back-to-back or staggered stud framing in many wall systems

If installation does not match the tested system specification, the FRL cannot be guaranteed — and the builder may be held liable for non-compliance.

Certifications and Compliance

Fire-rated systems must be certified according to AS 1530.4 and referenced in NCC documentation. Be sure to provide compliance documentation to certifiers and building surveyors.

Shop Fire-Rated Solutions

Explore our range of fire-rated plasterboard including Siniat Fireshield. We also supply fire-rated sealants, jointing compounds, and system specifications.

In the next chapter, we’ll look at acoustic plasterboard systems — used for soundproofing between rooms, floors, and commercial spaces.

Chapter 13: Acoustic Systems

Acoustic performance is just as important as structural and fire compliance in many projects — especially in multi-residential housing, offices, theatres, and media rooms. Plasterboard acoustic systems help reduce noise transfer between rooms and floors, contributing to comfort, privacy, and regulatory compliance.

Why Acoustic Control Matters

Sound travels through both air and structure. Without the right systems, noise from adjoining rooms (TVs, conversations, foot traffic) can quickly become disruptive. Acoustic systems absorb or block that sound, using specific plasterboard, insulation, and frame configurations.

Key Acoustic Performance Terms

• Rw: Weighted Sound Reduction Index – measures airborne sound insulation
• Rw + Ctr: Adjustment for low-frequency sounds like traffic or music
• Impact Sound Rating: Measures floor and ceiling footfall or vibration noise

Types of Acoustic Plasterboard

Acoustic plasterboard is denser and thicker than standard board. It has a higher mass which helps block airborne sound transmission between spaces.

Common Product:

Siniat 10mm Soundshield — used in bedrooms, media rooms, and intertenancy walls requiring improved acoustic control.

Acoustic System Components

• High-density plasterboard (one or more layers)
• Resilient mountings or furring channels to decouple board from frame
• Acoustic insulation (e.g., Earthwool or glasswool batts)
• Staggered or double stud framing to isolate sound paths
• Sealants: Acoustic sealant applied at perimeters and penetrations

System Types

• Single stud + insulation + acoustic board — common in internal partitions
• Double stud with separation + insulation — high-performance intertenancy walls
• Resilient channel systems — used in retrofits or high-spec commercial projects

Installation Tips

• Run acoustic insulation full height and width with no gaps
• Seal around electrical boxes and penetrations with acoustic sealant
• Ensure board joints are staggered in multi-layer systems
• Avoid rigid fixing through resilient channels

Compliance

Acoustic systems are covered under the NCC and must meet minimum Rw requirements in intertenancy and commercial walls. Builders may be required to provide system documentation or acoustic test certificates.

Shop Acoustic Boards

Find Siniat Soundshield and acoustic system components at Online Plasterboard Supplies — shipped Australia-wide.

Next up: we’ll explore finishing tricks for external corners, reveals, and curved features.

Chapter 14: External Corners, Archways and Reveals

While flat walls and ceilings make up most plasterboard installs, it’s the edges, openings and architectural features that take your finishing skills to the next level. In this chapter, we’ll cover how to tackle external corners, window and door reveals, and curved features like archways.

External Corners

External corners are the most exposed part of any wall and are prone to damage without reinforcement. They’re finished using corner beads — which provide both strength and a straight edge for jointing.

Types of Corner Beads:

• Metal corner bead: The most common — fixed with screws, nails or staples
• PVC corner bead: Non-corrosive, often used in wet areas
• Trim-Tex or specialty beads: Used for shadow lines, bullnose corners or custom profiles

Installation Tips:

• Ensure bead sits flush — use a level to check
• Secure at multiple points without distorting the shape
• Apply joint compound in thin coats — feather wide
• Sand lightly and check for high/low spots before painting

Window and Door Reveals

Reveals are the plasterboard surfaces that form the sides of a window or door opening. They may be square-set or trimmed with an architrave, depending on design preference.

Fixing Reveals:

• Use accurate cuts and tight joints for a clean square-set look
• Back-block internal reveals for strength where needed
• Use metal angles on external window edges to resist knocks
• Ensure reveals are plumb and square to the frame

Curved Features and Archways

Curved openings and ceilings create visual interest but require specialised handling. Most are formed using flexible plasterboard or multiple score cuts on the rear face of standard board.

Options for Curves:

• Flexible plasterboard (usually 6.5mm): Designed for tight bends — can be curved wet or dry
• Scored board: Standard board with the back face scored to allow bending
• PVC or custom arch beads: Used to maintain edge shape and protect from damage

Tips for Curved Installations:

• Pre-bend the board using gentle pressure — or wet with a sponge for tighter curves
• Use screws at tight intervals to hold the shape
• Feather joints slowly over multiple coats — curves show imperfections more easily

Mastering these finishing details gives your projects a professional edge and reduces call-backs. In the next chapter, we’ll cover the tools and equipment that make plasterboard work faster, cleaner, and safer.

Chapter 15: Plasterboard Tools and Equipment

Plasterboard installation and finishing rely heavily on the right tools. Using proper equipment not only improves the quality of your work, but also saves time, reduces waste, and keeps your worksite safer. Whether you’re an apprentice building your first kit or a seasoned pro upgrading your setup, this chapter covers everything you’ll need on site.

Cutting and Measuring Tools

• Utility Knife: Essential for cutting sheets — always keep spare blades
• T-square / Drywall Square: For long, straight scoring lines
• Tape Measure: Every apprentice’s best friend — double check all cuts
• Spirit Level / Laser Level: For checking stud alignment and sheet position

Handling and Lifting Tools

• Plasterboard Lifter: Great for ceiling installs — reduces fatigue and improves safety
• Sheet Carrier: Makes it easier to move large boards through tight spaces
• Panel Trolley: Used on commercial jobs for transporting multiple sheets

Fixing Tools

• Screw Gun / Drill with Clutch: Prevents overdriving screws
• Staple Gun or Hammer: For fixing corner beads or strapping
• Nail Bag or Tool Belt: Keeps fasteners and knives within easy reach

Jointing and Finishing Tools

• Broadknives: Typically 150mm, 200mm and 300mm for joint compound application
• Hawk or Mud Pan: Holds compound for easy access during jointing
• Sanding Pole or Hand Sander: Used with 180–220 grit paper to smooth joints
• Dust Mask / Respirator: Essential for sanding and cutting safety

Adhesives and Compounds

• Siniat Stud Adhesive — for bonding to framing
• Base Coat: Heavy-bodied for embedding tape
• Top Coat: Lighter and smoother for final feathering
• All-Purpose Compound: For small jobs or all-in-one usage

Safety Equipment

• Gloves (handling board and trimming beads)
• Steel-capped boots
• High-vis clothing and hard hat (on site)
• Eye and ear protection (especially for power tools)

With the right tools and setup, every stage — from sheeting to sanding — becomes faster, neater, and more efficient. In the next chapter, we’ll cover common mistakes and how to avoid them on plasterboard jobs.

Chapter 16: Common Mistakes and How to Avoid Them

Even experienced builders make mistakes with plasterboard — but for apprentices and DIYers, a few simple errors can result in cracking, sagging, or costly rework. Here’s a breakdown of the most common issues on site and how to avoid them.

1. Using the Wrong Type of Board

One of the biggest errors is using standard plasterboard in wet areas or fire-rated walls. Always check if the job requires:

• Moisture-resistant board (e.g. bathrooms, laundries)
• Fire-rated board (e.g. garage walls, intertenancy walls)
• Acoustic board (e.g. bedrooms, media rooms)

2. Overdriving Screws

Overdriven screws tear through the face paper, weakening the fixing and increasing the risk of joint cracks. Use a screw gun with a clutch or depth setting to control this — the screw should sit just below the surface, not buried.

3. Incorrect Stud or Joist Spacing

Too wide and your boards may sag or crack. For ceilings, 450mm centres are best. For walls, 600mm max — and heavy boards may need closer spacing.

4. Not Staggering Joints

Always stagger joints in walls and ceilings to prevent weak points. Avoid four-way joints where possible, or reinforce with back-blocking if unavoidable.

5. Poor Tape Application

If tape isn’t fully embedded or is applied over dry compound, it will blister or peel. Press firmly with your broadknife and apply a smooth, even layer of base coat underneath.

6. Skipping Back-Blocking

Especially in ceilings, skipping back-blocking leads to cracking or sagging at joins. Always back-block where required by the system spec — especially for recessed joints in large ceilings.

7. Not Leaving a Floor Gap

Plasterboard must not touch the floor. Leave a 10mm gap to prevent moisture wicking up from the slab — especially in wet areas or homes with slab-on-ground construction.

8. Poor Sheet Handling

Bent or chipped corners often happen during transport. Always carry sheets upright with two people, store them flat, and don’t drag them on the floor.

9. Rushing the Sanding

Rough or uneven sanding can ruin a perfect joint. Use proper sanding tools, work under a light to spot imperfections, and always wear a dust mask.

10. Failing to Seal Penetrations

Soundproof and fire-rated systems require that all gaps and penetrations (e.g. around GPOs, pipes) are sealed. Use acoustic or fire-rated sealant to maintain compliance.

Understanding and avoiding these mistakes will help deliver stronger, cleaner, and more professional results. Up next: we’ll compile a glossary of common plasterboard terms — perfect for apprentices and site newcomers.

Chapter 17: Glossary of Terms

This glossary is designed to help apprentices and new builders get familiar with the most common plasterboard and construction terms you’ll encounter on site. Use it as a quick reference when reading installation manuals, working with trades, or learning system specs.

Adhesive

A bonding compound used between plasterboard and framing. Often applied in daubs.

Back-Blocking

A method of reinforcing plasterboard joints (usually in ceilings) using narrow board strips glued behind the sheets.

Base Coat

The first layer of jointing compound used to embed tape and fill recessed joints.

Battens

Horizontal members fixed to framing to provide an even surface for plasterboard fixing, commonly used in ceilings.

Cornice

A decorative moulding used to cover the join between the ceiling and the wall.

Control Joint

An intentional gap or flexible joint designed to allow for building movement and prevent cracks in long runs of board.

FRL (Fire Resistance Level)

A rating that describes how long a system can resist fire — measured in minutes for structural adequacy, integrity, and insulation (e.g., 60/60/60).

Gypsum

A natural mineral (calcium sulfate) used as the core material in plasterboard.

Jointing Compound

A finishing material used to cover joints, embed tape, and feather out board joins.

Joists

Horizontal framing members that support ceiling plasterboard. Similar to floor joists, but in roof or upper floor frames.

Mastic / Sealant

Flexible sealing compound used in fire-rated and acoustic systems to fill gaps and penetrations.

NCC

National Construction Code — Australia’s building standard that all plasterboard systems must comply with.

Noggings

Horizontal braces installed between studs to provide rigidity and fixing points for board edges.

Plasterboard

A flat panel of gypsum core wrapped in paper, used for internal wall and ceiling lining.

Recessed Edge

A factory-formed edge on plasterboard that creates a channel for joint tape and compound.

Shadow Line

A square-set finish with a negative detail between the ceiling and wall for a clean, modern look.

Siniat

A leading manufacturer of plasterboard and finishing products used across residential and commercial projects in Australia.

Top Coat

The final layer of compound used to feather and finish a joint, applied over the base and second coats.

WR Board

Moisture-resistant plasterboard used in wet areas. Also known as wet area board or green board.