Due to the increasing use of fibre composites in the construction industry, wooden beams reinforced with composite elements in various forms are becoming a popular solution. In order to repair the existing structure or to increase the load capacity of new elements, various types of reinforcing elements in the form of tapes and bars are introduced into the cross-section. For unconventional methods to have applicational significance, it should be possible to estimate the deflection of the designed structural element (it is necessary to check SLS with the use of non-complex analytical methods. The method used to estimate the deflection of wooden beams reinforced with composites gives good results for elements reinforced with bars and several tapes glued to the lower lamella.