Plasterboard is a versatile and widely used building material that helps create smooth walls and ceilings.
What is Plasterboard?
Plasterboard (also called drywall, wallboard and gypsum board) is a common building material used in interior construction. It consists of a layer of gypsum sandwiched between two layers of paper. The gypsum core provides rigidity and some fire resistance, while the paper facings provide a smooth surface for finishing.
Once installed, plasterboard can be finished with joint compound, sanded and painted or wallpapered to create a smooth, uniform surface. Plasterboard is widely used due to its relatively simple installation and low cost.
History of Plaster
Learning a bit of history is always interesting, so here’s a timeline on plaster and how it’s been used over the years.
The use of plaster dates back thousands of years, with evidence of its use in ancient civilisations such as Mesopotamia, Egypt, Greece and Rome. Plaster was primarily made from lime, gypsum or a combination of both, mixed with water to form a paste that could be applied to surfaces for various purposes.
In Mesopotamia, around 7500 BC, gypsum plaster was used for sculptures and wall decorations. Ancient Egyptians used gypsum plaster and lime plaster (made form limestone) in construction and for decorative purposes in tombs and temples. Greeks and Romans used plaster extensively in their architecture, including for frescoes, sculptures and decorative mouldings.
Plaster continued to be used in construction during the medieval period, particularly in Europe, where it was applied over wattle and daub or lath and plaster structures. During the Renaissance, plasterwork became more refined, with elaborate decorative plaster ceilings and walls becoming prominent features in palaces, churches and other grand buildings.
During the Industrial Revolution, Gypsum began to be mined on a larger scale, and new techniques for processing and manufacturing plaster emerged. The invention of plasterboard in the early 20th century revolutionised the construction industry, providing a faster and more convenient alternative to traditional plastering methods.
Drywall vs. Plasterboard: What’s the Difference?
Drywall and plasterboard are the same product. Americans will typically call it ‘drywall’ whereas Australians will call it ‘plasterboard’.
Main Types of Plasterboard
Plasterboard comes in various types designed for different applications:
Standard plasterboard
This is the most common type of plasterboard used for general interior wall and ceiling construction. It typically consists of a gypsum core sandwiched between two layers of paper. Standard plasterboard is suitable for most residential and commercial applications.
Fire-resistant plasterboard
Fire-resistant plasterboard contains additives that improve its fire resistance properties. It’s designed to slow down the spread of flames in the event of a fire and is often used in areas where building codes require enhanced fire protection, such as corridors, stairwells and fire-rated walls.
Moisture-resistant plasterboard
Also known as green board, moisture-resistant plasterboard is manufactured with water-resistant additives in the gypsum core and moisture-resistant paper facing. It’s designed for use in areas prone to high humidity or moisture, such as bathrooms, kitchens and laundry rooms. Moisture-resistant plasterboard helps prevent mould and mildew growth and maintains its structural integrity in damp environments. Be aware that moisture-resistant plasterboard is not waterproof and should be kept as dry as possible. If water manages to seep through the wall you may end up with mouldy insulation, which is quite costly to replace.
Acoustic plasterboard
Acoustic plasterboard, also known as sound plasterboard or sound-rated drywall, is designed to reduce sound transmission between rooms. It features enhanced acoustic properties, typically achieved through denser gypsum cores or additional layers of specialised materials. As with acoustic insulation, acoustic plasterboard is commonly used in residential buildings, offices, hotels and other environments where noise control is important.
Impact-resistant plasterboard
Impact-resistant plasterboard is reinforced with fibres or other materials to improve its resistance to damage from impacts, such as bumps or dents. It’s suitable for use in high-traffic areas or environments where walls are prone to damage, such as hallways, schools and commercial spaces.
Flexible plasterboard
Flexible plasterboard, also known as curved plasterboard or bendable plasterboard, is designed to be easily bent or curved to fit irregular or curved surfaces. It is commonly used for creating curved walls and arches.
Where is Plasterboard Used?
Plasterboard is used for interior walls and ceilings. The process of installing plasterboard on walls involves affixing large sheets of plasterboard to wooden or metal studs using screws or nails. Ceiling plasterboard installation involves attaching plasterboard sheets horizontally to ceiling joists or rafters using screws or nails.
Plasterboard can snap if trodden on, so it’s important that ceiling insulation installers and other tradies working in the roof space move carefully. If you step on the ceiling plasterboard you can fall through and cause expensive damage!
Benefits of Using Plasterboard
Using plasterboard in home construction has many benefits:
- Quick and efficient installation.
- Versatility in design and decoration.
- Durable and long-lasting.
- Provides a smooth and uniform surface for finishing.
- Relatively cost-effective
- Lightweight, reducing structural load.
- Environmentally friendly, as gypsum is a naturally occurring mineral.
- Easily recyclable.
When disposing of your plasterboard, do not put it in your kerbside bins. Rather contact a local plasterboard recycling company who can take care of it for you. 1300 Rubbish states that as much as 94 percent of plasterboard waste can be recycled, with the recycled material being used by gypsum manufacturing companies to produce new plasterboard, amongst other things.
Disadvantages of Plasterboard
Unfortunately, there are some downsides when it comes to using and installing plasterboard. These include:
- Absorbs water quite easily, causing swelling and mould.
- Prone to dents and cracks.
- Poor soundproofing, especially if the wall isn’t insulated with thick thermal batts or acoustic insulation.
- Requires skill and patience for proper installation.
How to Cut Plasterboard
Plasterboard sheets generally come in 1200mm and 1350mm widths. Below is a summary on how to cut plasterboard:
- Measure and mark. Measure the area you want to install plasterboard on. Use a tape measure and a pencil to mark the dimensions you need to cut on the plasterboard sheet. Make sure your measurements are accurate.
- Score the face. Using a utility knife or a drywall saw, carefully score the face of the plasterboard along the marked line. If you’ve got a shaky hand, it could be helpful to have a long ruler, or spirit level to lean the knife against. Apply firm pressure to create a deep groove in the paper facing without cutting all the way through the board.
- Snap the board. Once you’ve scored the face, carefully bend the plasterboard along the scored line. The plasterboard should snap along the score line cleanly. If it doesn’t snap easily, you may need to make additional scores along the same line.
- Cut the back. After snapping the plasterboard, use your utility knife or drywall saw to cut through the paper backing on the backside of the board along the snapped edge. This will ensure a clean and smooth cut.
- Smooth edges. After cutting, use a rasp or sandpaper to smooth any rough edges along the cut edge of the plasterboard.
How Plasterboard is Installed
Installing plasterboard for both walls and ceilings involves similar steps, and generally you’ll start with the ceiling. Here’s a summary of the steps a plasterboard installer will generally follow:
- Ensure the wall/ceiling framing is in good condition and clear of any debris.
- Cut the plasterboard to fit the area using the steps in the above “How to Cut Plasterboard” section.
- Put a few small pieces of plasterboard along the bottom wall edge so there is a gap for flooring later on. They’ll be removed when finished.
- Apply walnut-sized blobs of stud adhesive/glue to the wall studs/ceiling joists, avoiding the end studs to prevent nails from lifting due to adhesive shrinkage. Apply adhesive only where needed for that sheet of plasterboard.
- If it’s a large sheet of plasterboard, ask a colleague to hold it in place for you. Secure the plasterboard sheets to the wall studs with plasterboard screws or nails. (A plasterboard installer will know the exact spacing for the screws to avoid damage.) It’s important to avoid screwing through the adhesive.
- Tape the joints between plasterboard sheets and cover with joint compound, smoothing with a drywall knife.
- Finish the seams by sanding them smooth and applying additional coats of compound if necessary.
- Prime and paint the walls once the joint compound is fully dried and smoothed.
It’s highly recommended you contact an experienced plasterboard installer if you’re unsure about the process.
Common Mistakes to Avoid When Installing Plasterboard
Plasterboard is a fragile material so it’s important to work with it correctly. Here are some common mistakes to avoid when carrying out a DIY plasterboard installation:
Rough handling
Mishandling plasterboard during transportation or installation can lead to cracks, chips or even breakage. It’s important to handle it with care and use proper lifting techniques.
Incorrect cutting
Cutting plasterboard inaccurately can result in uneven edges, gaps or misaligned pieces during installation. Measure twice and cut once, and use a straight edge and utility knife for clean and precise cuts.
Over-tightening screws
A couple of years ago we did a retrofit insulation installation in a small Sydney home, and a plasterboard installer was also working there, on a separate renovation. We happened to cross paths and I asked him what he was working on. He explained the task at hand (re-doing a poor plastering job), and mentioned that one of the biggest mistakes beginner or DIY plasterers do is tightening the screws too much.
He told that over-tightening screws can cause the plasterboard to crack or create dimples in the surface. You should always use the correct screw size and drive them in just enough to secure the board without causing damage.
Not providing sufficient support
Failing to provide adequate support for plasterboard panels can lead to sagging or bowing over time. Ensure that the framing is properly spaced and securely fastened to support the weight of the plasterboard.
Ignoring expansion gaps
Plasterboard needs room to expand and contract with changes in temperature and humidity. Failure to leave expansion gaps between panels or around the perimeter can result in buckling or cracking over time.
Poor joint preparation
Neglecting proper joint preparation can lead to visible seams and an uneven finish. Use joint tape and joint compound to fill and smooth the seams between plasterboard panels, ensuring a seamless surface.
Ignoring safety precautions
Working with plasterboard can create dust and debris, so it’s highly advisable to wear appropriate safety gear such as goggles, gloves and a dust mask. Additionally, be cautious when using tools such as utility knives and power saws.
Can You Paint Directly onto Plasterboard?
Yes, you can paint directly onto plasterboard. Just make sure you’ve sealed the plasterboard (so there are no gaps) and cleaned the surface. Then you can apply primer and paint in multiple coats for a durable finish.
How to Repair Damaged Plasterboard
If you’ve grown up in a family with many siblings or have kids yourself, you’ve probably had to deal with a hole in the wall more than once. Repairing damaged plasterboard is typically not a complicated job:
- Prepare the necessary materials such as joint compound, a putty knife, sandpaper, primer and paint.
- Remove any loose debris or old adhesive around the damaged area to ensure a clean surface for repair.
- Fill the damaged area with joint compound using a putty knife, smoothing it out evenly. For larger repairs, consider using self-adhesive mesh tape before applying the compound.
- Once the compound is completely dry, sand the area smooth using fine-grit sandpaper to blend it with the surrounding surface.
- Prime the repaired area to ensure proper adhesion and then paint it to match the surrounding wall or ceiling.
How Much Does Plasterboard Cost?
In Australia, the cost of plasterboard typically ranges from around $20 to $40 per sheet. Brand and quality will influence this price.
Where to Buy Plasterboard
You can buy plasterboard from a range of suppliers and retailers. Some popular places to purchase plasterboard from include:
- Gyprock
- Bunnings Warehouse
- Knauf (also the seller of Earthwool insulation).