The implementation of Universal Design in design practice requires a number of tools that provide support to designers throughout the design process. In recent years, several studies have been carried out, determining methods to help designers select appropriate design support tools (DSTs), looking for desired data representation characteristics, or focusing on involving a wide range of users in the design process. This paper discusses how architects, as end-users of the DST, are involved in the development process of a new web-based tool based on the Universal Design Patterns concept. The Universal Design Pattern concept was developed based on Christopher Alexander's Pattern Language, and looks at the possibility of using patterns to describe existing barriers in the built environment (conflicts), as well as design characteristics that may be implemented to make new designs more inclusive (resolutions). Through Universal Design Patterns, users can contribute new insights about the existing built environment, while architects can discuss the inclusive qualities of new design solutions or find useful design guidance. Involving the architects in developing the Universal Design Pattern concept into a web-based design tool is essential to establish a structure for the Universal Design Patterns that is compatible with the designers way of thinking about design problems. Using the specific structure of Universal Design Patterns allows for the grouping of information into appropriately themed units on different levels of the design in a clear and uniform way. Building on the results of a survey involving 406 architects and a comparative study of existing DSTs for Universal Design, this paper first focuses on the results of a series of interviews that provided the basis for a first data-structure for the Universal Design Patterns tool. In addition to this, case-studies were carried out to ensure the new tool can easily be incorporated into the architects design process. The results from both the interviews and the case-studies were combined in a preliminary model for the web-based tool. Finally, the methodology for testing this model with architects is discussed. In conclusion, some thoughts are given on the potential benefits of not only testing new DSTs with designers, but involving them actively from the early stages, or, in other words, the benefits of tools not only designed for architects, but with them.