The situation on the construction market is difficult. One way to improve it can be to implement modern methods and techniques related to the lean management in construction. The article presents an algorithm supporting the selection of appropriate Lean Management tools and techniques for construction companies using AHP method. The efficiency of the proposed algorithm is illustrated by a case study consisting of a small construction company performing insulation works in a multifamily house. The presented approach is part of the broader research work carried out by the authors in the field of improving construction processes and verifying the efficiency and effectiveness of Lean Management methods and techniques construction works.

Article presents the results of the effect of humidity on early shrinkage of normal concrete with variable W/C ratio. As known for a long time, shrinkage is dependent of many factors. One of them is the W/C ratio and the quantity of water which is located in the concrete mix. In article there were discussed changes taking place in the concrete mix, the methods of research and the partial results obtained by the authors of the paper. Shrinkage is a phenomenon well known and studied by various research centers. The total amount of shrinkage may depend on various factors such as humidity, temperature, composition of the concrete mix, the W/C ratio, the size of the item. The study was conducted to determine the amount of shrinkage in its early stages. It is very important for concrete floors contractors, precast manufacturers to start at the right time finishing work and prevent the formation of shrinkage cracks.