Extensions for Resin are threaded extension rods designed to lengthen the embedment of a resin-injected anchor without changing the original fixing procedure. They are used when the standard anchor or threaded rod is too short for the required depth, when accessing deep or restricted holes, or when extending installed anchors to take plates, rails or fittings after the initial resin has cured.

These extensions are supplied as male-to-male threaded studs manufactured in either carbon steel or stainless steel. Carbon-steel options are available in property class 8.8 to BS EN ISO 898-1; stainless options are offered in A2 (AISI 304) and A4 (AISI 316) grades to EN ISO 3506-1. Threads use ISO metric coarse form (M8–M24) to ISO 261/965, available as fully or partially threaded lengths depending on requirement. Finishes include bright passivated stainless, zinc plated electroplate and hot-dip galvanised to BS EN ISO 1461 for enhanced exterior corrosion protection.

In typical use the extension is screwed into the exposed thread of a chemically anchored stud, effectively transferring load through the cured resin body. They are compatible with the majority of injection resin systems and accessories used in post-installed anchors and are suitable for use with systems assessed under ETAG/ETA and current EAD guidelines when used according to the resin manufacturer’s installation instructions. Because extensions maintain the original thread profile and mechanical class, designers can predict load behaviour in accordance with the parent anchor’s design guidance.

Common applications include structural fixings in concrete and masonry, balustrade and handrail installations, facade anchoring, heavy machinery baseplates, installation of signposts and street furniture, and retrofit projects where deeper embedment or adjustments are required. The availability of stainless grades makes them suitable for coastal, marine and corrosive environments where long-term corrosion resistance is necessary.

Duchy Fasteners holds a practical stock range of resin extensions in M8 to M20 diameters and lengths from 50 mm up to 300 mm, supplied singly or in trade packs to suit site and workshop needs. If you require alternative lengths, materials or special thread classes, contact Duchy Fasteners for bespoke options.