Our modern society insists on the countryside reaching into the city. To make the urban environment more beautiful we make green roofs and improve the backyards by designing children's playgrounds and organizing recreational zones. We create a sustainable environment for future generations to have a comfortable life. However, one must not forget that the attractive green roofs of buildings are serious engineered structures. First and foremost the safety issues have to be taken into consideration during the construction and operation stages. On November 21, 2013 Maxima shopping center's roof collapsed in Riga, Latvia causing 54 deaths and creating international news. The collapse of the supermarket in the Latvian capital Riga has been described as "murder", by the country's president Andris Berzins. It is the deadliest disaster in Latvia since it regained independence in 1991. The causes of the collapse need to be studied in detail. This report is the authors' independent attempt to find the cause based on photographic evidence and literature observes. This article is based on a study conducted by the students and teachers of Latvia University of Agriculture. The article provides the reasons for this tragedy basing on the analysis. The author considers that the tragedy was the result of the coincidence of circumstances caused by mistakes in the calculation of building structures.

Abstract. The construction industry is considered to be a conservative industry, and, looking back into the history of the industry, modern digital tools have only started to play a role in a relatively recent period, but have already managed to significantly change the design, construction and management processes, their specifics, as well as the necessary competencies of the parties involved. This is mainly due to the third technological revolution, especially during the last two decades, when the extremely rapid development and availability of solutions of information and communication technologies has taken place. At present, in the private sector, companies operating in project supply chains (material manufacturers and suppliers, designers, builders) in the private sector can use the benefits of technology to increase their competitiveness and profitability. However, in Latvia, due to the public sector's order quantity and the fact that the demands on the project execution process are conservative in these orders, companies have so far been passive in introducing innovations. Companies in the supply chain of construction projects are not the only ones who can benefit from the use of new technologies. Among the winners are project contractors in both the private and public sectors. Therefore, it is necessary in construction study programs of universities to integrate BIM training by improving the content of the study program in accordance with the new demand. The research task is to find out the necessary knowledge, skills and competences of the graduates of university for working in so complicate managing process. It is also important to find out how to improve the study program according to the new and complex view from the first steps of construction to the operation of the building.

The aims of the research are to investigate the durability and compliance of patented innovative low or zero heat energy cons umption buildings constructions by Latvian construction standards. To develop and study high-quality, energy-efficient and long-lasting low-cost eco-buildings construction technology by using locally sourced building materials and involving local labo ur, using various low-cost recyclable ecological materials and their recycling residues as eco-thermal insulation. Because of the research, it was established that by using building materials of appropriate size cross-section -spruce boards and interconnecting them with screws, it is possible to make a sufficiently strong building construction frame where are in accordance with Latvian construction standards by using a significantly smaller amount of building materials. By filling the frame of the innovative construction building with thermal insulation in the appropriate thickness, it is possible to build up houses with high energy efficiency that correspond to the parameters of low or zero heat energy consumption buildings. In climatic zones, where for buildings have increased energy efficiency and thicker layer of thermal insulation requirements, it is expected that double windows and door s design solutions will be used to reduce heat loss of cold bridges, and the air gap between them increase the energy efficiency of buildings.

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.

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