Adding storeys and extensions with modular construction
Pacarada Modular Building Systems, Kelkheim (Taunus), Germany · Last updated: September 2026
Adding storeys creates new living or working space without additional land. Modular construction is particularly well suited to this: components are prefabricated in the factory, the work on the existing building takes less time, and the comparatively light construction with steel or timber puts less load on the existing structure.
Why added storeys are in demand
Building land in cities is scarce. On many existing buildings, whether residential blocks, offices, supermarkets or car parks, additional storeys can be built. Roads, utilities and often stairwells are already in place and are shared. No additional land is sealed.
Why modular construction works on the roof
- Less time on site: The modules are made in the factory while the roof is prepared. Assembly on the existing building is quick, so residents and tenants are affected for less time.
- Lower weight: Steel and timber modules are lighter than solid construction with concrete and masonry. That improves the chance that the existing building can carry the additional storeys.
- Dry construction: Bolted and plugged instead of poured and bricked, with very little wet work.
- Adapting to the existing building: In the Pacarada system columns and beams (1D), wall and floor elements (2D) and room modules (3D) can be combined, so the new structure can follow the grid of the existing building.
- Stairs, lifts, facade: The system also includes stair and lift modules, facades and roofs.
What has to be checked first
Every added-storey project starts with a survey of the existing building. Can the structure and foundations take the additional load? Does the building class change, and with it the requirements for fire protection and escape routes? Are stairwell, lift and building services sufficient? Then there are the local development plan and the required distances to site boundaries. The structural engineer, architect and building authority clarify these questions before production starts.
Examples from our projects
Darmstadt, Holzhofallee 36: A vacant office building was converted into 197 homes, with bathroom modules in the existing building, an extension and added storeys. Construction took 18 months, 44% faster than conventional construction; the building meets the KfW 55 standard.
Liederbach am Taunus, Höchster Straße 1C: 30 apartments from 33 modules were built above a refurbished supermarket. Columns and beams, wall and floor elements and room modules were combined in one building. Shopping below, living above: the same plot is used twice.
Frequently asked questions
How many storeys can be added?
That depends on the load-bearing capacity of the existing building, planning law and fire protection. A structural survey of the building gives a reliable answer. The Pacarada Modular Building System itself is designed for buildings from 1 to 50 storeys.
Can residents stay in the building while storeys are added?
That depends on the project, above all on the work on the roof, stairwell and building services. Because the modules are prefabricated in the factory, the construction time on the occupied building is usually shorter than with conventional construction.
Do added storeys need a building permit?
As a rule, yes. In Germany the building code of each federal state defines which documents are required. Plan the permit early, ideally in parallel with the structural survey of the existing building.
More articles in the modular building guide
- Modular or conventional construction? A comparison
- Modular schools and nurseries
- Steel modular and hybrid construction: steel, timber and concrete combined
- What drives the cost of modular construction
- Back to the overview: modular building guide
Planning a project? Send us your enquiry, ideally with drawings. You will find all system data on our Facts and figures page.