Hybrid Balcony


Designing, manufacturing and erecting concrete balconies applied in traditional multi-storey residential concrete buildings are painful if not impossible in some cases. Indeed, it may imply several constraints among which the need of steel reinforcement in the main structure to support the heavy cantilevered concrete slabs adding potential thermal bridges at the same time. Special insulated connections might be used to mitigate this, but it remains quite expensive. Focusing on a standard concrete balcony 2 meters wide by 3,5 meters long by using a wooden Kerto LVL Q-panel to replace the concrete slab would allow standards 1,8m – 2,4 or 2,5 meters wide balconies in link with Q-panels standard widths. Then having a timber massive panel supported on each side by a steel UPE 300 beams will make it easy to prefabricate by steel or wood offsite manufacturers. This LVL panel can also bring fire resistance or serve as a fire deflector from one storey to another. Surface underneath (meaning for the lower level) can be covered but may remain visible with appropriate coating and covering on top will include a waterproofing layer either liquid or solid (membrane or steel tray) + decking.

Key benefit

A hybrid balcony that can be prefabricated using a steel main structure and Kerto LVL Q-panel floor slab is 5 times lighter than a cantilevered concrete slab and reduces thermal bridges due to the need of reinforcement in the main structure.

Material list

- Peripheral metal Beams (UPE300) + Metal Ties

- Kerto LVL Q-panel on underside (63 to 75mm - Hold on 4 sides - Slope 3%)

- Waterproofing complex and Weep Holes

- Blocks supporting a Wooden Planking

- Railings and Decorative Panels

Ecological values

Hybrid constructions may open new ways to improve sustainability globally. Finding new elements or building systems integrating partly wood that suit traditional construction is an important topic for which we need to share local ideas and innovations. Reducing fossil based solutions by adding bio-based material such as Kerto LVL will enable faster, lighter and greener constructions. 1,5m3 of concrete slab replaced by min 0,4m3 of Kerto-LVL panel storing at least 315kg CO2 Hybrid balcony 5 times lighter than a standard concrete balcony : from 4 tons to 0,8 tons



  • Economical span (mm)
  • Thickness (mm)
  • Airbourne sound reduction factor (dB)
  • Impact sound transmission (dB)
  • Resistance to fire class
  • Thermal properties



Filename Size




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