Stropy

Stropy is the plural form of strop in Polish and is used in architecture and construction to refer to the horizontal structural elements that form the floor and ceiling assemblies between storeys of a building. In English-language contexts these elements are typically described as floor slabs and ceilings. The strop transfers loads from the upper structure to vertical supports and provides horizontal stiffness and separation between levels.

Stropy can take several forms depending on the building method. Traditional wooden construction uses timber joists with plaster or lath coverings. Modern construction typically employs reinforced concrete slabs, including solid slabs, ribbed slabs, or hollow-core slabs, sometimes with a concrete topping or finishing layer. Precast concrete stropy and steel decking systems are also common in multi-storey buildings and parking structures. The choice of system depends on factors such as span, architectural requirements, fire resistance, and cost.

Key design and performance considerations for stropy include load-bearing capacity, fire resistance, acoustical isolation between levels, thermal performance, moisture protection, and durability. Maintenance may address cracking in concrete, moisture damage, or timber decay. Proper detailing at joints, openings, and connections to walls, columns, and stair or elevator cores is essential for overall structural integrity and occupant comfort.

While the term is chiefly used in Polish-language contexts, the underlying concept—horizontal floor/ceiling assemblies that separate building levels—exists in all building traditions under different terminology. Stropy thus describe a fundamental element of structural design and interior organization in many constructions.