I decided to take my topic of designing of reinforced slabs for a residential building from a little different angle. At the time I started with thesis I had only very little idea about how design decisions influence final price of project. I decided to model four simple solutions and estimate the price. Based on this results and combination of other factors I would choose the best solution and perform detailed calculation to obtain proper design of horizontal load bearing structure for building. Finally I would like to go back to simple design and compare the accuracy of methods. This way we could see if our assumption were based on valid data. My general goal for the thesis is to get better understanding of design solutions and final costs, accuracy of preliminary design as well as the work load for such activity.