A contextual design is sensitive when a new construction wants to add within historic district or areas contain a significant number of historic buildings. Intervention to historic contexts especially addition and infill design have always been a big issue in the preservation field. For the new addition into urban historical context there are no simple rules for achieving quality of design   in the new addition, although a clear and coherent relationship of all the parts of the new work to the whole, as well as to the setting into which it is introduced is essential. New work should aspire to a quality of design and execution related to its setting, which may be valued both now and in the future. In shaping the built environment it is important to have a responsibility to past, present and future generations. Therefore, Infill work or design in a historic context should be linked the past to the present and projects into the future. This neither implies nor precludes working in traditional or new ways, but demands respect for the significance of a place in its setting. 
In the contemporary architectural addition and designs in Iran’s historical context, it is not seen a favorable interaction between historical sites and new parts. Until about 50 years ago, these interactions were less damaged by and protected against the effects of new interventions and constructions, due to the presence of traditional architects and the continued use of some deep-rooted architectural patterns, but the damage to historical buildings and collections gradually increased over time by moving away from genuine social and physical patterns. Part of this process, due to the lack of theoretical foundations and a holistic and principal approach, has practically made our historical cities disturbed and greatly distorted their historical and architectural identity. The contextualist approach, therefore, states that historical buildings, in addition to reaching a suitable appearance for living, should reflect the delicacies of traditional Iranian architecture. 
This study is an applied, descriptive and analytical research that is carried out based on the case study using data collection, desktop study, and field research, referring to historical documents and performing qualitative analysis. Moreover it is intended to provide clear and objective recommendations for the restoration or rehabilitation of structures, as well as new construction on vacant parcels or additions to existing buildings within the city’s old and historic districts. While portions of it are dedicated to other topics such as repair, maintenance and fascinating architectural history. 
After data collection and review of the physical and visual factors involved in such interventions of historical buildings and complexes, European countries such as Germany, Austria, and the Czech Republic, have been examined. While visiting them, different aspects of intervention, including the used materials, the relationship between historical and modern elements from the general and partial perspectives, the joints between new and old sections, etc. have been explored. Finally, it was attempted to provide some design guidelines that would physically organize the interventions performed in historical buildings and collections. 
These guidelines are to encourage redevelopment that is compatible with the existing character of the city’s core as well as continue to preserve the character of the existing neighborhoods. Continued regional growth has increased developmental pressures in the city’s core. These guidelines are targeted, but can also apply to new development outside of the area. The design guidelines serve as a reference for property owners, developers, residents, and public officials responsible for reviewing development plans within the area. 
The criteria are meant to address the exterior appearance of buildings. The guidelines are not intended to prohibit creative approaches to individual building designs, or to promote architectural uniformity. It is the intent of this document to foster collaboration between the Context and the developer/builder early in the design process of a redevelopment project. 
The goals of redevelopment projects is for them to reflect an understanding of the immediate site surroundings and context character. The projects should consider existing features including massing, height, setbacks, proportions, scale, roof forms, materials, articulation, lighting, signs and awnings while creating appropriate architectural design. It is a particularly useful resource for property owners, occupants, landlords, members of the design and construction professions and anyone wishing to alter a property within an old and historic district.