Masonry Concrete Expansion Bolts — Carbon Steel Wall Anchor Screws M6 to M20

Match the thread diameter to your fixture's hole size (e.g., M8 for an 8 mm hole). For length, add the fixture thickness to the minimum embedment depth — typically 25–40 mm for M6–M10 and 40–60 mm for M12–M20. For example, a 20 mm thick bracket on concrete generally calls for an M8 x 60 mm (≈ 2-3/8") or M8 x 70 mm (≈ 2-3/4") bolt. When in doubt, go one size longer.

Load capacity depends on bolt diameter, embedment depth, and base material strength. In general, M6 bolts typically handle lighter loads (up to ~1 kN shear in standard concrete), while M16–M20 bolts can handle significantly higher loads. Always consult a structural engineer for safety-critical applications such as overhead fixtures or fall-arrest anchors.

These bolts are carbon steel. For occasional moisture exposure, a protective coating or sealant is generally recommended after installation. For permanently wet, coastal, or marine environments, stainless steel anchors are a better long-term choice. Contact us to confirm suitability for your specific conditions.

These are metric ISO thread bolts following standard M-series pitch specifications. They are compatible with standard metric nuts, washers, and fixtures. Thread pitch varies by diameter — M6 is typically 1.0 mm pitch, M8 is 1.25 mm, and M10 is 1.5 mm. They are not compatible with UNC/UNF (inch) threaded hardware without adapters.

These expansion bolts are designed for use in solid concrete, brick, and dense masonry block. They are generally not suitable for hollow walls, drywall, lightweight aerated concrete (AAC), or soft materials without additional anchoring hardware. For hollow block, consider a sleeve anchor or chemical anchor instead.

1. Drill a hole matching the bolt diameter using a hammer drill and masonry/carbide bit. 2. Clean dust and debris from the hole with a brush or compressed air. 3. Insert the expansion bolt into the hole. 4. Position your fixture over the bolt. 5. Thread on the nut and tighten with a wrench — this draws the bolt upward and expands the sleeve against the hole wall, creating a secure mechanical anchor. Do not overtighten, as this can crack the surrounding masonry.

We offer flexible quantity options from 1 piece up to 100 pieces per size. For small repairs or single fixtures, 1–5 pcs is typically sufficient. For larger projects like deck post bases, pergola footings, or equipment mounting frames, ordering 10–50 pcs provides a cost-effective buffer and covers any installation extras. Bulk quantities (30–100 pcs) offer the best per-unit value.

Yes — anchoring post bases, angle brackets, and structural hardware to concrete slabs is one of the most common uses for these expansion bolts. Select a diameter that matches your bracket's bolt holes (typically M8–M12 for standard post bases) and a length that provides adequate embedment into the slab, generally at least 50–80 mm of embedment depth depending on load.