Whether you’re building a new home in Perth or tackling a renovation, you’ll need to choose the right flushing products — and that starts with knowing the difference between all-purpose drywall compound and finishing top coat plaster.
What is drywall compound?
Drywall compound — also referred to as joint compound, top coat plaster, or base coat plaster — is a gypsum-based paste used in the flushing process (also known as joint taping). It helps create smooth, even finishes across plasterboard walls by covering recesses, fixing imperfections, and hiding screw or nail heads.
You’ll find drywall compound in two forms:
- Pre-mixed, ready to use from the bucket
- Powdered, requiring water and mixing before application
Some compounds dry faster, others are easier to sand, and many vary in weight and shrinkage, so it’s important to choose the right type for the job.
Understanding the Flushing Process (aka Joint Taping)
If you’re new to flushing, here’s a quick breakdown of the three-step process used by flushers (or plasterers):
1. Flushing (or Joint Taping)
When two plasterboard sheets meet, they form a recess. To strengthen this recess, flushers apply a paper or mesh tape over the recess. This is set in place using a base coat plaster or all-purpose compound as the bonding layer.
- Paper tape requires a compound beneath it to adhere.
- Mesh tape has a sticky backing, but still needs compound over the top.
This step builds structural strength and sets the base for a seamless finish.
2. Bedding
Once the tape coat has dried, a second layer of compound — usually a base coat or all-purpose again — is applied to fill and level out the joint area. The goal is to conceal the taped recess and create a consistent surface.
3. Finishing
The final coat is all about getting a smooth, flawless surface ready for paint. This is where finishing top coat plaster is typically used — it’s lighter, sands more easily, and gives that clean, polished look required for higher finish levels (Level 4 or Level 5).
However, all-purpose compound can also be used for the finishing coat, especially on standard residential builds or smaller projects. It’s a practical choice when you want one product for the entire flushing process, from first coat to final finish.
For a premium result — particularly in well-lit areas or commercial interiors — most flushers and plasterers still opt for a dedicated finishing compound for the third coat, due to its workability and finer texture.
Once dry, this final coat can be lightly sanded, leaving the wall ready for paint or final sealing.
Plasterboard Finishing Levels
With the three-step flushing in mind, you can easily categorise the current state of a plasterboard’s finish in levels as follows:
- Level 0: Bare, installed plasterboard
- Level 1: Joints and fasteners have been taped, without any additional drywall compound
- Level 2: Tape has been embedded with a coat of drywall compound
- Level 3: A third coat of drywall compound is applied. Many unseen plasterboards, such as above ceilings, can be left at this level.
- Level 4: Another full layer of compound. This is the usual standard for most applications according to the Australian Standard Requirements under plasterboard installation standard AS 2589:2017. Sanding can already be done after this level.
- Level 5: The full wall is layered with a final skim coat of drywall compound. The highest level of finishing, with the smoothest surface.
The higher the level of finish, the smoother your plasterboard surfaces will be.
All-Purpose Compound vs Finishing Top Coat Plaster
Now that we have a general idea of the flushing process, how do you know which compound to use for the process? You’ll most likely encounter all-purpose drywall compounds and top coat plaster when shopping for your building materials, but each has its uses in the three-step flushing process.
All-Purpose Drywall Compound
Typically on the heavier side of drywall compounds, all-purpose drywall compound, as the name implies, can be used for all three steps of the flushing process and is sold pre-mixed in a bucket. With a slower drying time, it’s much more forgiving on beginners looking to DIY any repairs or renovations. Take into account that all-purpose drywall compound has more shrinkage when applying the first coat during taping.
For all-around plasterboard flushing and finishing jobs, we highly recommend the following products, tried and tested by professional builders and DIYers alike:
Westgyp Platinum – Multi Purpose Compound
Westgyp’s own specially formulated Australian-made multi-purpose compound was made based on our 30 years of experience in the industry. Specially manufactured to withstand the West Australian climate, it’s the perfect all-purpose drywall compound for any Perth build.
- Lightweight
- Pre-mixed
- Professional grade
- Backed by manufacturer’s warranty
Hamilton All-Purpose Compound
Another great option if you’re looking for an all-purpose drywall compound is the Hamilton Joint Compound. It also suits Australian standards and offers great workability.
- Lightweight
- Pre-mixed
- Professional grade
- High bond
Finishing Top Coat Plaster (Drywall Finishing Compound)
Can I use top coat as base coat plaster?
This is a common question, and the short answer is no. Finishing top coat plaster is designed only for the final (third) coat. It’s not formulated to bond properly in the first and second coats. If you’re not using an all-purpose compound, you’ll need a base coat plaster for those earlier layers to ensure structural strength and durability.
Plaster top coat is lighter, easier to sand, and delivers a high-quality surface, perfect for Level 4 and Level 5 finishes.
For a smooth, seamless finish on your walls, we recommend:
Siniat Mastaglide Finishing Compound
Perfect for achieving a smooth Level 5 finish, Siniat’s Mastaglide Finishing Compound has a smooth, creamy consistency with an advanced formula that reduces air bubbles and offers excellent crack resistance as it dries.
- Easy to apply
- Easy to sand
- Works for both hand and machine applications
Knauf LiteFinish™ Finishing Compound
Another best-seller for drywall finishing compounds is the Knauf LiteFinish™ Finishing Compound. Providing a smooth, final coat on joints, angles, and fastener heads, this finishing top coat leaves the surface with a light, creamy texture that works great in achieving a Level 5 finish.
- Low shrinkage
- Easy to sand
- Easy to apply
How do they compare in real-world use?
To better illustrate the uses of all-purpose compound and finishing top coat, here’s a summary of their functions and qualities at a glance.
Uses & Key Characteristics
| Taping | Bedding | Finishing | Finish Quality | Ease of Sanding | Ideal Use Case | |
| All-purpose Drywall Compound | ✔️ | ✔️ | ✔️ | Level 1 to Level 5 | Easy | From start to finish of flushing |
| Finishing Top Coat | ❌ | ❌ | ✔️ | Level 4 to Level 5 | Very Easy | Smooth to final skim coat |
What’s ideal for Perth homes?
Choosing what’s best to use boils down to the kind of project you’ll be doing.
For Perth’s climate and building standards, we recommend using:
- All-purpose plaster compound for flexibility, speed, and cost-efficiency
- Finishing top coat plaster compound when aiming for premium results or working with light-critical areas
Both perform well under local conditions, but the right choice depends on your desired finish level and project scope.
Find the perfect plaster base coat and top coat for your project with Westgyp
Westgyp is here to help you plan your project from start to finish. With 30 years of experience supplying construction materials and plasterboard throughout WA, our team can help guide you so that you use the right materials for the project at hand. Call us now if you need some assistance with drywall compounds.