Task / Solution:
The task was to plan an extension of a 2-story commercial building.

The solution is actually somewhat unusual, as the extension cantilevers about 2.10 m over the existing building. The simple reason for this was that the existing two-story building could only be structurally
could "tolerate" an additional floor, but the legal distance requirements were still not exhausted.

With the cantilevered extension, we were able to increase the gross floor area from 695 m2 on the existing floors to 960 m2 (i.e. by around 37%) and utilize the clearance areas that were approved under building regulations.

Result:
A lightweight wooden construction!
The new, 26 cm thick cross-laminated timber ceiling rests on new ring beams above the existing, 18 cm thick reinforced concrete roof ceiling, which, although it would not have been able to withstand additional traffic loads, now serves well as a fire barrier below.
However, the facade and roof loads of the extension are transferred to the existing building via a steel girder grid. The new cross-laminated timber floor slab only supports itself and the traffic load of the
Extension. It is doweled to the ring beams and secured with inserted springs and
Equipped with X-fix connectors for thrust transmission.

All walls of the extension - with the exception of the two stiffening stairwell cores - are simple post and beam constructions that were delivered pre-tied and then timbered and installed.

The roof deck consists of prefabricated, approximately 18 m long, 2.49 m wide "Pi panels", consisting of two supporting ribs made of GL75 beech and a ceiling mirror made of 39 mm thick KERTO-LVL panels.

For the shear resistance between these KERTO panels, very flat X-fix connectors are used, which were specially designed for this construction project and approved by the manufacturer within a very short time !