Anchoring resin, also known as a chemical anchor, is a two-part bonding system made up of a resin and a hardener. The two components mix as they are injected into a pre-drilled hole via an applicator gun. A threaded stud, bolt or bar is then inserted into the filled hole. As the resin cures, it bonds chemically to both the substrate and the fixing element, creating a hold that is typically stronger than the surrounding masonry itself.
Chemical Anchor Resins for Concrete, Brick and Masonry Fixings
Anchoring resins, also called chemical anchors or bonded anchors, bond steel studs, threaded bars and bolts directly into concrete, brick, stone or blockwork using a two-part resin and hardener. The resin is injected into a pre-drilled hole, the fixing is inserted, and once cured the result is a bond that often exceeds the strength of the surrounding material itself. MacBlair stocks a range of injection resin cartridges suited to a variety of substrates and load requirements.
Choosing the right resin type matters. The three main options are polyester, vinylester and epoxy, each suited to different conditions. Polyester suits general, non-structural fixings in dry conditions. Vinylester handles damp substrates and is the better choice for outdoor or wet-hole applications. Epoxy takes longer to cure but delivers the greatest bond strength, making it the go-to for structural work. Common applications include:
- Gate posts and hinges into brick or stone
- Steel beam bearing plates and structural brackets
- Handrail and balustrade fixings
- Satellite dish mountings and antenna brackets
- Rebar connections and post-installed anchors
Unlike expansion anchors, resin fixings place no outward stress on the substrate. That makes them well suited to fixing close to edges, into hollow block with a mesh sleeve, or into masonry of uncertain quality. Hole preparation is critical: dust and debris left in the hole will prevent a proper bond, so always blow out and brush the hole before injecting. For complementary mechanical anchors and fixings, MacBlair stocks those separately within the fixings range.
Curing times vary by resin type and temperature. Fast-setting formulations can be ready to load in as little as 15–30 minutes, while epoxy resins may need 24 hours or more at lower temperatures. In Northern Ireland's climate, working in cold or unheated spaces will extend cure time significantly, so always check the manufacturer's data sheet before loading a fixing. Pair anchoring resins with threaded bar and the right nuts and washers to complete a full fixing assembly.
Anchor Resin FAQ's
Polyester resin is the most economical option and works well for general, non-structural fixings in dry conditions such as gate posts or bracket anchors in solid brick. Vinylester resin performs better in damp or wet conditions and is suitable for outdoor applications and hollow block with a mesh sleeve. Epoxy resin offers the highest bond strength of the three, with slower cure times, and is typically specified for structural applications such as steel beam bearing plates or rebar connections where maximum load capacity is required.
Yes, but a mesh sleeve must be inserted into the drilled hole first. The sleeve contains the resin within the void and prevents it from being lost into the hollow core of the block. Without a sleeve, the resin will simply fill the cavity and there will be no solid bond. Check the manufacturer's data sheet for the correct sleeve diameter for your chosen stud size. Polyester resin is not recommended for this application; vinylester is the better choice for hollow substrates.
Cure time depends on the resin type and the ambient temperature. Fast-setting polyester resins can be ready to load in as little as 15 to 30 minutes in warm conditions. Epoxy resins may need up to 24 hours or longer, particularly in cold weather. Temperature has a significant effect: the colder the substrate, the slower the cure. Never load or stress a fixing until the manufacturer's stated cure time has fully elapsed at the actual temperature on site, as premature loading is one of the most common causes of anchor failure.
This is one of the most critical steps in the installation process. If dust and drilling debris are left in the hole, the resin bonds to that contamination layer rather than to the masonry itself, resulting in a weak fixing that can pull out under load. Always blow out the hole with a pump and scrub it with a cleaning brush, repeating the process at least twice before injecting the resin. Also discard the first small bead of resin squeezed from a new nozzle, as the two components may not be fully mixed at the very start of the cartridge.