Expansion Anchor Bolts for Masonry — M6 to M16, Stainless Steel & Zinc-Coated

A general rule of thumb: the anchor embedment depth should be at least 10× the bolt diameter. For example, an M8 bolt typically needs at least 80mm (≈3.1") of embedment into the base material. Add the thickness of the fixture being fastened to get your total bolt length. When in doubt, go longer — you can always use a washer to compensate for extra protrusion.

Quick reference: M6 → min. 60mm embedment · M8 → min. 80mm · M10 → min. 100mm · M12 → min. 120mm · M16 → min. 160mm.

Load capacity depends on bolt diameter, embedment depth, and the compressive strength of the base material. In standard concrete (generally C20/25), an M8 expansion anchor typically handles approximately 2–4 kN in tension and 3–6 kN in shear under ideal conditions. Larger diameters and deeper embedment generally increase capacity. Always consult a licensed structural engineer for load-critical or life-safety applications.

The 304 stainless steel variants are suitable for most outdoor, humid, and mildly corrosive environments. For coastal areas or highly aggressive chemical environments, 316 stainless steel is generally recommended. The 201 stainless steel variants are best for sheltered or indoor use. Zinc-coated variants are intended for dry indoor applications only and will corrode if exposed to prolonged moisture.

These bolts use standard metric coarse threads (ISO 68-1), compatible with any standard metric nut or washer of the same diameter. M6, M8, M10, M12, and M16 are internationally standardized sizes available at most US hardware stores. They are not compatible with UNC/UNF (inch) threaded hardware.

These expansion anchor bolts are designed for solid concrete, brick, and solid masonry block. They are generally not suitable for hollow concrete block (CMU), aerated autoclaved concrete (AAC/Ytong), drywall, wood, or soft materials. For hollow substrates, a toggle bolt or sleeve anchor is typically more appropriate.

304 Stainless Steel — Contains 18% chromium and 8% nickel; excellent corrosion resistance for outdoor and humid environments. The most widely used stainless grade for fasteners.

201 Stainless Steel — A lower-nickel, higher-manganese alloy; cost-effective with moderate corrosion resistance. Suitable for dry or mildly humid indoor applications.

Zinc-Coated (Galvanized) — Carbon steel with an electroplated zinc layer for basic rust protection. Most economical option; best for dry interior use. Available in bulk packs of 10.

Yes. You will need a carbide-tipped masonry drill bit matching the anchor diameter (e.g., a 10mm bit for an M10 anchor). A hammer drill (rotary hammer) is strongly recommended for concrete and hard masonry — a standard drill will struggle and may damage the bit. Drill depth should match or slightly exceed the required embedment length. After drilling, clear the hole of dust before inserting the anchor.