Frequently Asked Questions

What is a mesh sleeve and why is it needed for the Lokfix RA system in hollow blocks?

A mesh sleeve (also called a screen sleeve) is a cylindrical tube made of metal or plastic mesh with an open lattice structure. In hollow block anchoring, the mesh sleeve is inserted into the drilled hole (which passes through the solid face shell of the block into the hollow core). When resin is injected into the mesh sleeve, the resin fills the sleeve and partially penetrates the mesh openings to contact the solid material of the block face shell and any webs. The mesh prevents the resin from flowing freely into the hollow core of the block and being lost. The result is a short column of resin-impregnated mesh that is bonded to the solid material in the drilled hole and provides adequate load transfer from the anchor to the block. Without the mesh sleeve, the resin would disappear into the hollow cell and the anchor would have no structural support.

Can Lokfix RA be used in wet masonry substrates?

The performance of the Lokfix RA resin anchor in wet masonry depends on the resin chemistry used. Standard polyester-based resins (similar to Lokfix E45T) have reduced performance in wet substrates. If the masonry is wet (for example, from rain or rising damp), an epoxy-based resin that is specifically formulated for wet-substrate anchoring should be used instead. Always drain the hole of any standing water before injecting the resin. For anchoring in permanently damp or underwater masonry, consult the Fosroc technical team through Space Arc Engineering for guidance on the appropriate resin system.

What loads can Lokfix RA anchors support in hollow concrete blocks?

The characteristic load capacity of Lokfix RA anchors in hollow concrete blocks depends on the block strength, the wall thickness, the anchor diameter, the embedment depth, and the anchor spacing and edge distance. Hollow block load capacities are significantly lower than the equivalent anchor in solid concrete — a typical hollow block anchor in a standard 200 mm hollow block might provide a design tensile load of 1 to 5 kN depending on the block quality. These are adequate for light to medium fixings such as pipe supports, light shelving, and conduit brackets, but are not appropriate for structural fixings, heavy equipment, or safety-critical applications (stairs, railings with fall protection requirements). For heavier loads in masonry walls, solid grouted cells with embedded anchors or structural steel backing plates should be used.