Poradnik
Filigree or in-situ slab? A comparison for designers and investors
A filigree floor is a composite slab: a precast slab more than 5 cm thick acts as permanent formwork, and the structural whole is only created by the in-situ topping poured on site. An in-situ (monolithic) floor is built entirely on site — on formwork that has to be erected, propped and, once the concrete has matured, struck.
What you gain with a filigree floor
- No formwork. The slab arrives from the factory with the bottom reinforcement and lattice girders already in place. What remains on site is laying the top reinforcement and pouring the concrete — the most labour-intensive stage of an in-situ floor disappears.
- A ceiling ready for finishing. The underside of the slab is formed on a steel production table, so it is smooth. Filling the joints is usually all that is needed, with no plastering of the whole ceiling.
- Openings cut in the mould. Service penetrations and the stairwell opening are in the slab from the start — there is no breaking out after the concrete has been poured.
- A shorter storey cycle. Laying the slabs proceeds at the pace of the crane, and propping is sparser than the full support formwork requires.
When the advantage disappears
Filigree slabs need a crane on site and sensible delivery logistics — on a plot that a vehicle carrying slabs up to 12 m long cannot reach, an in-situ floor may be the only option. With highly irregular floor plans the number of non-standard slabs grows, and the price with it. A composite floor also has to be dimensioned earlier: changing the wall layout after the slabs have been ordered is costly.
Parameters worth knowing
Our filigree slabs are up to 2,50 m wide and up to 12 m long, with a total floor thickness of 14–40 cm. A 5 cm slab weighs around 125 kg/m², concrete up to C35/45, and the minimum bearing on the wall is 20 mm. The full technical data can be found on the filigree floor slabs page.
If you are comparing offers for a specific project, send your floor plans through the quote form — we will calculate the floor in both thickness variants and select the spans.