Tying Wire for Rebar Fixing

What Is Rebar Tying Wire?

Tying wire (Bindedraht in German) is a soft, annealed steel wire used to fix reinforcing bars at their intersections before concreting. It does not contribute structurally — it simply holds the cage in the designed geometry while concrete is placed and vibrated. Once the concrete has set, the wire’s job is done, though it remains permanently embedded in the structure.

Despite its seemingly minor role, inadequate tying leads to cage distortion, bar movement during vibration, and loss of the specified cover — directly undermining the structural and durability performance of the finished element.

Wire Specifications and Gauges

Standard rebar tying wire is made from low-carbon steel, annealed (softened by heat treatment) to give it the flexibility to be twisted tightly without breaking. The most common specifications are:

Wire is supplied in pre-cut and twisted loop form (pre-formed ties, ideal for automatic tying guns) or in raw coil form for manual twisting with a hook tool. Pre-cut ties in lengths of 150–250 mm are standard for tying gun use.

Tying Methods and Patterns

Several tying patterns are used depending on the element and access:

• Single wrap: one loop of wire around both bars, ends twisted together; quick but lower holding force — adequate for mesh intersections where bars are in contact.
• Double wrap: wire looped twice before twisting; stronger grip, used on larger bars and at critical positions (ends of laps, column corners).
• Cross tie (figure-of-eight): wire crosses between bars before twisting; prevents the bars from rotating relative to each other; preferred at stirrup corners and for columns.
• Saddle tie: wire bent into a U, placed over the crossing bars and ends twisted underneath; fast and reliable for slab mat assembly.

For large projects, automatic rebar tying guns (e.g. MAX RB series) using pre-loaded wire reels dramatically increase productivity — a trained operative can tie several hundred intersections per hour with consistent pull-out resistance.

Corrosion Considerations

Plain annealed iron wire begins to corrode once exposed, but once encased in concrete the alkaline environment (pH 12.5–13.5) passivates the wire and corrosion essentially ceases. However, the wire tie ends must be bent inward — away from the concrete surface — to ensure they are not within the cover zone. Wire ends close to the surface can act as initiation points for rust staining and surface cracking.

In aggressive exposure classes (XD, XS) some specifications require galvanised or stainless steel tying wire. Galvanised wire (zinc-coated) provides short-term protection during cage assembly and delays corrosion initiation; stainless wire (typically grade 304 or 316) is specified for the most aggressive environments (XS3, tidal/splash) and for architecturally exposed concrete where surface staining is unacceptable.

Tying Wire vs. Welding at Bar Intersections

Welding rebar intersections (instead of tying) is possible and used in precast and prefabrication environments, but requires compliance with DIN EN ISO 17660 (welding of reinforcing steel). B500B is weldable when carbon equivalent (Ceq) is within limits — the MTC confirms this. Tack-welding at intersections in general structural work is generally not required and may even be prohibited by the structural engineer if it affects the parent bar properties. Tying wire remains the standard for on-site cage assembly.

Ordering Tying Wire with Your Rebar Package

Steel Rebar Germany can include annealed tying wire coils in the same export consignment as B500B bars, coils, mesh, and accessories. Standard supply is 1.2 mm or 1.6 mm annealed black wire in 1–5 kg coils, or pre-cut ties for gun use. This consolidates logistics and ensures you receive a complete reinforcement package at one destination port with one shipping document set. See also our guides on spacers and chairs for concrete cover and welded mesh lap requirements. To request a combined quote, visit our quote page.