The production of a concrete floor constitutes a remarkable share of the production costs of a concrete-framed apartment building and tasks in the frame construction stage. The right choice of the structure affects the pro-ject’s completion schedule and sales revenue. The purpose of this thesis was to examine and compare two most common used concrete floor struc-tures i.e.a hollow-core slab floor and cast-in-situ floor. The thesis was commissioned by Jatke Uusimaa Oy.

The aim was to find a more profitable floor structure for modern apartment buildings. The primary purpose was to discuss the production methods and costs of the floor structures and the schedule of the frame phase when building a typical one-staircase-apartment building. An actual apartment building site was chosen for this study to represent a typical one-staircase-apartment building in construction. The example building was built of a hollow-core slab floor. It was examined how the production methods, costs and schedule would have changed if the building’s floor structures had been built as a cast-in-situ floor.

The costs caused by the floor structure were calculated with an Excel-based program. In the calculations were used the tender calculation and post calculation information commonly used by Jatke Uusimaa Oy. Assis-tance was also received from the staff of Jatke Uusimaa Oy. Information on production methods and schedule was acquired from the example building, by interviews and from written and electronic sources.

As a result of the thesis, hollow core slabs were concluded to be a better choice for a floor structure in one-staircase-apartment building projects. Based on the results hollow-core slabs would be at least 9 €/m² cheaper and the frame phase schedule would be one week briefer.