Abstract. One of the most important parameters that is currently used in public and private procurement in building process is the lowest price. The legislation of Latvia permits that an estimate forming process does not include criterions of quality, durability, and the potential high cost of maintaining the building during the exploitation time. That allows the constructor to reduce the cost estimate by using cheaper construction product or technology and does not let to provide the highest possible quality and the basic principle of sustainable construction. One of possible construction cost reduction solutions is the replacement of building material with equal building material, at the same time assessing the quality and replacement impact on the direct costs of estimate. The tasks of the research are:(1) to do literature review on what is an estimate, what an estimate includes and the basis of estimate; (2) to analyse the existing construction estimate, to evaluate the used construction materials and to study technical characteristics of materials, to explore a specific construction junction; (3) to replace the selected construction materials with analogous, thus reducing the direct costs of estimate; (4) to evaluate the affect of the price of the construction material on quality; (5) to compare the obtained cost estimate with the current cost estimate; (6) to implement laboratory research and to compare technical characteristics of the construction materials and analogue materials in order to check if they are the performing parameters that are defined in the declaration of performance. After comparing of the obtained direct costs of construction and analysing the quality of construction materials it is possible to provide the most appropriate offer of the direct costs of estimate to satisfy the customer's interests.