Lattice Girders for Precast & Filigree Slabs
Lattice girders (Gitterträger) are precision-welded 3-D truss reinforcement elements that give precast concrete filigree slabs, double walls, and insulated panels the stiffness, shear transfer, and erection strength they need — all to DIN 488-5 and EN 10080.
What Is a Lattice Girder (Gitterträger)?
A lattice girder is a continuous, factory-welded three-dimensional truss made from reinforcing steel wire or rod. It consists of three longitudinal chords connected by a zigzag diagonal: one top chord (the compression element during handling) running at the apex of the truss, and two parallel bottom chords that sit on the formwork or precast shell. A continuously welded diagonal wire runs from top chord to each bottom chord in alternating V-patterns, creating a rigid spatial frame.
In German precast practice the term Gitterträger is used interchangeably with “lattice girder.” The element is produced in standard lengths (typically 1.0–12.0 m) and cut or ordered to the exact panel length required. Standard steel grade is B500A or B500B per DIN 488 / EN 10080 — the same compliant reinforcing steel used throughout German construction.
Typical Geometry Ranges
Lattice girders are specified primarily by their overall height (h) — the distance from the bottom-chord centre to the top-chord centre — and by the chord diameters. Common height designations run from approximately 60 mm to 200 mm (labelled h60 through h200 in many producer catalogues). Chord diameters range from ø 5 mm to ø 12 mm depending on the height class and structural requirement. The bottom-chord spacing (truss width) is typically 100–150 mm. This range of geometries means a single product family can serve thin 60 mm precast shells up to thick double-wall panels or heavily loaded composite slabs.
| Height label | Approx. girder height (mm) | Typical use case |
|---|---|---|
| h60 – h80 | 60 – 80 | Thin filigree slab shell (≥ 50 mm precast layer) |
| h100 – h120 | 100 – 120 | Standard Elementdecke, residential & commercial |
| h150 – h160 | 150 – 160 | Heavier-span composite slabs, industrial floors |
| h180 – h200 | 180 – 200 | Double walls (Doppelwand), deep composite elements |
Structural Functions of Lattice Girders
Three critical roles in every precast element that contains them.
Handling & Transport Stiffness
A filigree precast shell is only 50–80 mm thick — far too flexible to lift off the casting bed without cracking. The lattice girder acts as an integrated spine: its truss geometry converts bending forces into axial chord loads, keeping the thin panel rigid during demoulding, transport by flatbed, and crane erection on site.
Composite Shear Connection
Once the in-situ concrete topping is poured over the precast shell, the lattice girder’s top chord and diagonals project into the topping layer and become the primary shear connector between precast and cast-in-place concrete. This composite action allows the combined slab to behave as a monolithic section under imposed loads — meeting the requirements of Eurocode 2 (EN 1992-1-1) for composite slabs.
Supplementary Flexural Reinforcement
The bottom chords of the lattice girder contribute directly to the tensile reinforcement area of the finished slab. Engineers can account for this cross-section when calculating the required mesh reinforcement (reinforcing mesh), often reducing the mesh specification and overall steel tonnage in the element.
Products and Systems That Use Lattice Girders
Filigree Slab / Lattice-Girder Slab (Elementdecke)
The Elementdecke (filigree slab or lattice-girder slab) is the most common application. A thin reinforced precast concrete shell — typically 50–80 mm — is manufactured in the factory with bottom-mesh reinforcement and lattice girders cast in at regular centres (usually 200–600 mm apart depending on span and load). On site the panels are placed on temporary props, additional top reinforcement is laid, and a structural concrete topping is poured. The result is a fully composite floor slab combining factory precision with site flexibility. Lattice-girder slabs are used throughout Germany and the EU in residential, commercial, and industrial construction.
Double Wall (Doppelwand)
The Doppelwand (double wall or twin wall) consists of two parallel precast concrete leaves — typically 60–80 mm each — held apart by lattice girders that bridge the cavity between them. The cavity is filled with in-situ concrete on site to create a monolithic load-bearing or shear wall. Taller lattice-girder heights (h150–h200) accommodate the required wall thickness. Double walls offer fast erection, good acoustic mass, and an excellent surface finish on both faces.
Insulated Sandwich Panels
In thermally insulated precast sandwich panels, modified lattice-girder connectors bridge the insulation layer, connecting the outer architectural leaf to the inner structural leaf. Stainless steel or coated variants are specified where corrosion resistance across the insulation gap is required.
Relationship to Reinforcing Mesh
Lattice girders work in conjunction with — not instead of — reinforcing steel mesh. Bottom mesh provides the primary flexural reinforcement in the precast shell; top mesh in the topping controls shrinkage and provides the upper compression zone reinforcement. The lattice girder links the two layers and provides the shear transfer between them. For precast concrete applications requiring a complete reinforcement package, Steel Rebar Germany can supply both mesh and lattice girders to the same order.
Standards & Certification
Lattice girders for use in the German/EU market are governed by the following standards:
- DIN 488-5 — Reinforcing steels; Part 5: Reinforcing steel mat and lattice girder. Specifies material requirements, geometry tolerances, welded joint strength, and marking.
- EN 10080 — Steel for the reinforcement of concrete. Weldable reinforcing steel. Applies to the rod and wire material used in manufacturing the chords and diagonals.
- EN 1992-1-1 (Eurocode 2) — Design of concrete structures. Governs how engineers use lattice girder contribution in structural calculations for composite slabs.
- DIN EN ISO 17660 — Welding of reinforcing steel. The resistance-spot or flash-butt welds joining diagonals to chords must comply with this standard.
Material traceability is documented via EN 10204 Type 3.1 Mill Test Certificates, available with every consignment. Full export documentation — Certificate of Origin, packing list, and CE/Declaration of Performance where applicable — is supplied as standard. See our Standards & Certification page for further detail.
Frequently Asked Questions
What is a lattice girder and how is it different from a rebar spacer?
A lattice girder (Gitterträger) is a structural, factory-welded 3-D truss with a top chord, two bottom chords, and continuous welded diagonals. It serves active structural functions: handling stiffness during transport, composite shear connection between precast and in-situ concrete, and supplementary flexural reinforcement. A rebar spacer is a passive positioning device that holds reinforcement at the correct cover depth — it carries no structural load. Lattice girders and spacers are used together in a precast element, not instead of each other.
What is a filigree slab (Elementdecke) and why does it need lattice girders?
A filigree slab (Elementdecke or lattice-girder slab) is a semi-precast floor system: a thin (50–80 mm) factory-made reinforced concrete shell is erected on temporary props, then completed with an in-situ concrete topping poured on site. Without lattice girders, the thin precast shell would be too flexible and fragile to crane-lift and handle without cracking. The lattice girder’s truss geometry gives the shell sufficient stiffness for demoulding, transport, and erection. Once the topping is cast, the projecting top chord and diagonals lock the two concrete layers together into a composite slab — eliminating the need for separate shear connectors.
Which standard governs lattice girders in Germany and the EU?
The primary product standard is DIN 488-5, which covers both reinforcing steel mat (mesh) and lattice girders. It specifies material, geometry, welded joint performance, and marking requirements. The base steel material must comply with EN 10080. Structural design using lattice-girder slabs references EN 1992-1-1 (Eurocode 2). Weld quality is governed by DIN EN ISO 17660. All lattice girders supplied by Steel Rebar Germany are accompanied by EN 10204 Type 3.1 Mill Test Certificates confirming compliance.
What heights and chord diameters are available?
Standard height designations (centre-to-centre top to bottom chord) range from approximately h60 to h200 — that is, 60 mm through 200 mm in standard steps (h60, h80, h100, h120, h150, h160, h180, h200). Chord diameters are typically ø 5 mm to ø 12 mm for the top chord and ø 4 mm to ø 8 mm for the bottom chords and diagonals, depending on height class. Lengths are available from approximately 1.0 m to 12.0 m and can be cut to order. Contact us with your panel dimensions and structural specification and we will confirm available sections and pricing.
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