Easier, faster and dry – adding another story with precast concrete floor slabs

Building plots are scarce in many towns and communities. But new living space can also be created with an additional story. “In many buildings there is literally still room for expansion upward,” says Christof Wirth, Executive Manager at Dennert Baustoffwelt. His suggestion: With precast concrete floor slabs, adding an additional floor is faster and easier than using half-finished precast floor slabs that must be topped with an additional layer of in-situ structural concrete and supported for about four weeks from below until they reach required bearing capacity.

As an example, the precast specialist from Schlüsselfeld in the Upper Franconia region of Germany cites the DX precast floor slab. Whereas precast slabs with in-situ structural concrete topping weigh approx. 550 kg/m², the DX floor slab weighs only 330 kg/m². Because it has a thickness of only 20 or 24 cm and features a system of hollow cores that can be used for installing supply and cable channels. The low weight, moreover, noticeably relieves the existing masonry.


Simply add one

Another critical advantage – in particular, when adding a floor to residential buildings – is the fast erection involved. Every floor slab is prefabricated 100 % in the plant, can dry on the building, is erected nearly without any support and can be immediately walked on. Dennert executes erection with its own team within a few hours. In this way, the workflow can be reliably planned; the structural shell is quickly closed and rainwater has no chance to penetrate.

 “With half-finished precast floor slabs, in contrast, the factors concerning working hours, manual work, time and materials expenditure on site are markedly higher. They can be walked on not before approximately two days after installation and must be supported for four weeks until they reach bearing capacity”, explains Christoph Wirth.

Subsequent ring-anchor and joint grouting is also easier to handle with the DX floor slabs from Dennert. They require approx. one-tenth of the concrete quantity needed by half-finished floor slabs.

Their hollow-core system allows DX floor slabs still more additional options. Fitted with a pipe system containing circulating water, the false floors can heat the apartment below. With a high share of heat radiation, they ensure comfortable warmth without stirring up dust. Filled with cold water, they keep rooms comfortably cool.

With DX floor slabs, single- and two-family homes can by extended by an additional story, and garages with flat roofs, as well as supermarkets, can become building space. Extension by an additional floor is also possible on industrial buildings.


Dennert Baustoffwelt
GmbH & Co. KG

Veit-Dennert-Straße 7

96132 Schlüsselfeld/Germany

+49 9552 71-0


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