Throughbolts

A Trade Guide to Throughbolt Selection and Correct Installation

Throughbolts are the backbone of structural steelwork, heavy timber framing, and machinery mounting, relying on mechanical friction to secure heavy loads into non-cracked concrete. When choosing the right expansion anchor for your project, environmental exposure is your primary consideration. For general indoor building projects, warehouse racking, and enclosed dry environments, standard Zinc Plated Throughbolts offer exceptional tensile and shear strength along with excellent cost efficiency. However, if your installation will be exposed to moisture, coastal air, or harsh industrial chemicals, you must upgrade to corrosion-resistant Stainless Steel Throughbolts to prevent material fatigue over time.

Because a throughbolt relies on an expansion clip biting into the substrate as the nut is torqued, proper hole preparation is absolutely vital to the safety of the fixing. Always use an industrial masonry bit that precisely matches the diameter of your bolt, and drill down slightly past the required embedment depth. Before hammering the anchor home, use a blow-out pump or wire brush to remove all leftover concrete dust from the hole. If you leave dust trapped inside, the wedge sleeve won't grip cleanly, which can significantly lower the anchor's maximum load rating. For close to edge applications where the expansion pressure of a throughbolt risks splitting your concrete masonry, we suggest browsing our Ankerbolts Collection for a low-stress, self-tapping alternative.