Two key issues in the Swedish construction industry are to increase productivity and improve safety. Productivity in the Swedish construction industry is considered low in comparison to other industries. Previous studies have shown that 30-35% of buildings' total production cost can be categorized as waste, since the activities are non-value-adding for customers. The safety is important because the Swedish construction industry has twice as many serious work accidents than other industries. This combined with that many companies create products that are not based on customers' needs has led to the creation of a model named ‘Developed value stream mapping’. The models objective, which consists of four steps, is to generate product development suggestions based on a set of parameters (Customer needs, P2, P3,..., Pn). The core of the model is to analyze the relation between product characteristics and the parameters. The researcher chose, depending on the study’s background, to analyze the relation between product characteristics, customer needs, waste at the construction site and safety for construction workers. The model was tested on the company BAC Såg och Hyvleri products; roofing board and the newly developed roofing board with an integrated membrane. After choosing products, a current state was identified through interviews with customers and two site observations, where one product was used at each site. This step is performed to gain understanding of the products purpose and how the product is being processed on site. Main findings in identifying customer needs were that roofing boards should stabilize the roof and be adapted after distances between roof trusses. It was also found that customers wanted the company to manufacture customized roofing boards for each project and develop products that reduce dangerous time on roofs for construction workers. A number of quality-related issues were observed at the second observation where roofing board with an integrated membrane were used, of which the largest problem was that membranes were not sealed in the splices. In terms of assembly time, roofing board with an integrated membrane, depending on roof characteristics, is approximately 2,7-6,0 % shorter than roofing with the traditional roofing board. The time saving only applies if membranes are sealed in splices, which was not the case in this study. In the third step product characteristics are analyzed against waste at the construction site, safety for construction workers and customer needs. Roofing boards with the standard dimension of 3600x540 mm weighs 23 kg and the newly developed product weighs 24,6 kg, which means that managing roofing boards can lead to repetitive strain injuries in a short and long term perspective. Further, roofing boards' standard dimension results in that construction workers spend about 70-80 % of their working time on activities that are non-value-adding for customers. Waste at construction sites would with the customer proposal for customized roofing boards shorten the assembly time up to 50 %, increase customer satisfaction and reduce the risk of work-related injuries. Thus, BAC Såg och Hyvleri has great potential to improve efficiency in construction sites by developing roofing boards. The recommendation for the company is to stop the current development of roofing boards with an integrated membrane since it increase waste on construction sites. Product development suggestions are, amongst others to start producing customized roofing boards and improve roofing board fitting. Furthermore, the study shows that ‘Developed value stream mapping’ works since product development suggestions have been generated.