The financial aspects are becoming more and more important in the construction industry now-adays, hence the structures tend to be more economical, lighter and slenderer. Therefore, the stability of the large span structures is a typical key question. The main frame of hall structures is braced by the purlins on the upper flange of the beams. In the case of any uplifting load the loss of stability of the main beam still needs to be considered unless the lower flange is supported adequately. To solve this issue, which is an interesting design chal-lenge, rafterstays can be effective and convenient answer. The following thesis work discusses the consequences of the application of rafterstays regarding to the global structural behavior, through a steel industrial hall example. After finding an optimal geometry and size for these supporting elements, it was also the matter of thesis work how we can take their influence into account for sizing the adjacent structural members. The main beam of the frame has a corrugated web, therefore all verifications after the structural analysis were done according to the corresponding parts of the European Standards. In the relevant chapters a simplified method was developed to consider the effects of rafterstays on the stability of the beam. The method uses substitutional spring stiffness values for the rafter-stay-purlin system. Then the corresponding equivalent force on the lower flange was calculated on these models. The next chapter discusses the optimal geometry of rafterstays under design load. In order to find the suitable arrangement of the members, several configurations and variations were examined with different inclination, geometry of single- and double rafterstay system as well. The purlins and the rafterstays were sized for all configurations and I found the most ideal arrangement for them. To design and verify the purlins I followed the -Eurocode 3 - Design of steel structures - Part 1-3: General rules - Supplementary rules for cold-formed members and sheeting-. The rafter-stays are designed on a basis of common examples and they are assessed and verified by a method according to this standard.