M4–M8 Metal Drywall Expansion Bolts | Hollow Wall Anchors for Plasterboard & Drywall

Measure your drywall thickness first — typically 12mm (1/2") or 15mm (5/8"). The bolt length should generally be at least 2–3× the drywall thickness so the sleeve can fully expand behind the board. For example, a 20mm bolt suits thin single-layer drywall, while 52mm or 65mm bolts are better for thicker assemblies or when hanging heavier loads. When in doubt, size up rather than down.

Load capacity depends on the bolt diameter, length, head type, and the condition of the substrate. Generally, M4 anchors are suited for light fixtures and cable management, M5–M6 for shelving brackets and medium loads, and M8 for heavier items such as TV mounts or grab rails. Always verify the specific load rating against your project requirements and local building codes before installation.

These are metal fasteners and may be susceptible to corrosion in continuously wet or outdoor environments. For bathrooms or kitchens, they are generally suitable for occasional moisture exposure. For fully outdoor or high-humidity applications, consider pairing with a waterproof sealant or contact us to confirm the finish specification of your chosen variant before purchasing.

These are metric-threaded fasteners (M4, M5, M6, M8) following standard ISO metric thread profiles. They are not compatible with UNC/UNF imperial thread systems. Ensure your mating hardware — nuts, inserts, or fixtures — uses the same metric standard. If you need imperial sizing, please contact us before ordering.

The letter types refer to different head or body configurations — such as flat-head, pan-head, or variations in the sleeve mechanism — that suit different installation scenarios and fixture profiles. Type A variants are typically shorter and suited for flush-mount applications, while B through F offer progressively longer shanks or alternative expansion mechanisms for thicker substrates or higher-load situations. Select based on your fixture's mounting hole diameter and the wall assembly depth.

Most variants can be installed with a standard screwdriver or power drill. However, for consistent and professional results — especially in production or renovation work — we also offer dedicated installation tools compatible with M4–M5 and M4–M8 bolt sizes, available as a separate variant on this listing. Using the correct tool helps ensure the sleeve expands evenly and achieves full holding strength.

Yes. These expansion bolts are specifically designed for hollow substrates including standard drywall (gypsum board), plasterboard, and cavity walls where there is no solid backing. The expanding sleeve grips the back face of the board to distribute load. They are not intended for solid masonry or concrete — use a masonry anchor for those applications.

Match the bolt diameter to the mounting hole in your fixture and the load you need to support. As a general guide: M4 for lightweight items (picture frames, cable clips), M5 for light shelving and hooks, M6 for medium shelving brackets and curtain rails, and M8 for heavier fixtures such as TV brackets, grab rails, and cabinet fixings. Always check the fixture manufacturer's recommended fixing size where available.