If you're mounting something on a plasterboard wall — a TV, mirror, shelf, or cabinet — choosing the right plasterboard fixing is what keeps everything safely on the wall instead of crashing to the floor.
Have a look at the video guide to learn how to choose the right hollow wall anchor
The simplest way to choose the correct plasterboard fixing is to check three things before you start drilling:
These three details tell you whether the fixing is strong enough, whether it will expand properly in the wall cavity, and whether the screw length is suitable for the job. It sounds basic, but this is where most installation mistakes happen. A fixing might look right in the pack, but if it is too short, too weak, or not suited to the wall thickness, it will not perform as it should.
For most heavier applications on plasterboard, a metal hollow wall anchor is a safer and stronger option than a standard plastic plug.
A plasterboard fixing is a type of fixing designed specifically for hollow walls, including plasterboard, drywall, and similar sheet materials. Because there is open space behind the board, ordinary wall plugs do not have enough material to grip into properly. That is why specialised fixings are needed.
Hollow wall anchors work by expanding behind the board once installed. This creates a clamping effect that helps distribute the load across a wider surface area. Instead of relying only on the face of the plasterboard, the fixing uses the cavity behind it to create a much stronger anchor point.
They are commonly used for mounting items such as:
In most cases, plasterboard fixings used for heavier items are made from metal rather than plastic. That extra strength makes a big difference when the object being mounted has real weight or may be under regular strain.
The first question to answer is simple: what does the item actually weigh? Every plasterboard fixing has a maximum load rating, and that rating should always be checked before installation. It is not enough to guess based on size alone, because a small TV can still be surprisingly heavy, and shelves often end up carrying far more weight than expected once they are in use.
As a general rule, lighter decorative items may work with self-drilling plasterboard fixings, while heavier items are better suited to proper hollow wall anchors. The heavier the load, the more important it becomes to use a fixing that is designed specifically for that level of stress.
Typical examples include:
One important thing people often overlook is that the working load is not just about the object itself. A shelf might be light when empty, but once books, tools, or decorative items are added, the total weight can rise quickly. Always calculate the likely loaded weight, not just the weight straight out of the box.
Good to know: each hollow wall anchor should be able to support the total weight of the object, not just a share of it. So if you are putting up something that weighs 20 kg, each anchor should ideally be rated for 20 kg. Two fixings rated for 10 kg each do not give you the same level of safety.
This is especially important with plasterboard because the wall surface itself can weaken over time if the load is pushing the fixing beyond what it was designed to handle.
Once the object weight is clear, it is worth taking a step back and thinking about the wall itself. Even the best fixing can only do so much if the plasterboard construction is not suitable for the load. Thicker or layered plasterboard walls usually offer better support than a single, thinner board.
| Plasterboard Type | Approximate Load Capacity |
|---|---|
| Single plasterboard | 15 kg per m² |
| Double plasterboard | 25 kg per m² |
| Triple plasterboard | 35 kg per m² |
This table gives a rough guide to how wall construction affects load handling. It is useful when you are deciding whether the fixing alone is enough, or whether you should be fastening into studs or another supporting structure behind the wall.
If you are mounting anything heavier than around 15 kg, it is smart to think beyond just the fixing pack. At that point, the strength of the plasterboard wall itself becomes part of the equation.
The next step is checking how thick the wall is. This matters because a hollow wall anchor needs enough room to expand correctly behind the plasterboard. If the fixing is too short for the wall thickness, it may not open fully. If it is the wrong size altogether, it may not grip securely once tightened.
Plasterboard sheets are made in a range of thicknesses, usually between 3 mm and 13 mm. In many homes, though, the real wall thickness depends on how many boards are layered together.
Common examples include:
This is why it helps to know not just that the wall is plasterboard, but how it is built. A fixing that works perfectly in a single board wall may not be the right option for a double-board construction. The more accurately you match the fixing to the wall thickness, the better the anchor will perform.
If you are unsure, checking the edge of an opening, using a small pilot hole, or referring to building details can help you work out the depth before choosing the fixing.
Once you know the wall thickness, the final measurement is the thickness of the item you are mounting. This is the part that determines the screw length you need. It is easy to overlook, but it makes a real difference to whether the anchor can be installed correctly.
The screw needs to be long enough to pass through:
If the screw is too short, the fixing may not expand fully. If it is too long, installation can become awkward and the fixing may not tighten properly. A correctly matched screw length helps the anchor seat firmly and pull everything tight against the wall.
This is particularly important with brackets, shelves, and fittings that have a thicker mounting plate. Even a few extra millimetres on the object can affect which anchor size is correct.
Yes, in practice they are the same thing. The two terms are often used interchangeably, and both refer to fixings designed for hollow wall constructions like plasterboard.
The term hollow wall anchor tends to focus on how the fixing works — it expands behind the board and anchors into the cavity. The term cavity wall fixing focuses more on where it is used. Either way, you are talking about a fixing designed to create a secure hold in a wall that is not solid all the way through.
They are also different from simple plastic wall plugs, which are normally intended for solid materials such as brick, concrete, or blockwork.
Once you have checked the weight, wall thickness, and object thickness, the product packaging should be much easier to read. You are usually looking for three key bits of information:
If all three match your project, you are usually on the right track. This is also the point where it helps to choose a fixing from a brand that provides clear installation guidance, since the right technical details save a lot of trial and error on the wall.
Many plasterboard fixing kits include everything needed to get started, which makes the job a bit simpler, especially if you do not want to second-guess drill sizes or screw compatibility.
Some packs include:
That means you get the right hole size for the fixing and the right screw for the anchor, helping to reduce installation mistakes. It also makes it easier to get a neat, reliable result on the first go.
Once you have matched the fixing to the object weight, wall thickness, and screw length, you are in a much better position to mount your item safely and confidently.