Slab-edge fixed subframe

In a slab-edge, or inter-floor, system the main vertical rails are fixed to the floor slabs and not to the wall between them. Wind load and cladding weight are carried by reinforced concrete, which is much stronger than light masonry or hollow blocks. This is why the scheme is chosen for high-rise buildings, framed structures with infill walls and facades where anchoring into the wall is unreliable.

How it works

Heavy brackets, of reinforced series with larger projections, are anchored into the slab edge. Box-shaped or U-shaped rails then run from floor to floor to form a vertical frame, and the cladding is hung on this frame, sometimes with an intermediate light grid. The infill wall, thermal insulation and ventilation cavity sit behind the frame, free of load.

Advantages

Fewer fixings into weak wall materials
Clear transfer of loads to the structure
Good for large projections and thick insulation
Allows bigger distances between supports with deeper rails
Suited to cassettes and larger-format panels

Design points

Floor-to-floor height controls rail depth and weight.
Thermal and structural movement between floors must be absorbed by sliding joints.
Slab edges must be surveyed, as their tolerance is usually larger than that of finished walls.
Anchors are placed with edge distances and reinforcement in mind.
Fire stops at each floor are easier to arrange, since the rail passes close to the slab.

For buildings above 12 m, Georgia's Chapter 14 of the Building Safety Rules (Resolution No. 41 of 2016) applies, and the system is designed with this in mind. Tbilisi's seismic zone also adds load checks.

Pricing is on request. Send us your section drawings and we will prepare a calculation.

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