Architecture is one of the types of arts, which is distinguished by its special nature by expressing the era in which it is present, including political, economic and intellectual variables, in addition to its visual physical reality that affects man, in modern architecture on its various schools and philosophies we see that architecture is characterized by fixed structures that have the characteristics of sterility and lack Flexibility, does not allow addition or deletion of them, and that is inconsistent with the concept of sustainability, which aims to meet the needs of users and the ability to develop to cover renewable requirements that arise in the future after construction, so we find a breath in front of buildings that need expansion in the spaces or to add ml S of the original building as in museums or theaters and hospitals, hence the design solutions that allow the addition of a building or internal or external floors or voids by using light materials such as wood and metal structures inspired by the same spirit of the building to reach design solutions that have the character of compatibility with the original building and are complementary For the general shape of the building, and express the characteristics of the era in it with a new formula to link the old with the modern. Problem of the research: 1. The problem lies in the contradiction between what is old and what is new and it is an eternal contradiction that does not have a single solution, as the old still has its fragrant and still has talk of charm, dazzling and beautiful, and achieving complementarity between them is a problem that must be solved by consensus or contrast. Objectives: 1. Achieving complementarity between emerging formations and existing ones that carry a certain identity and character. 2. Reaching a comparative analytical approach through which we can measure the success of the reciprocal relationship between the existing and the new. Major results: 1. The compatibility in the architectural formation between the existing and the new comes in several forms, which are symmetry, similarity, overlap and camouflage, while the difference between what is existing and what is emerging is in two forms, namely the total contrast and partial contrast. Integration can be achieved between what is existing and what is emerging by studying the formal characteristics of the old and trying to simulate them on the proposed design treatments with the creation of new patterns that enhance the visual taste of the old formation