Abstract
The subject of the paper is an analysis a new building investments impact on the already existing buildings in a tight, compact city construction. The problem was discussed in two ways in the paper. Firstly, by identifying a group of factors that are caused by a new construction investments which could effect on neighbouring objects. Secondly, by correct technical condition assessment of existing buildings, methods for improving it or using technologies, that are also aimed to minimising the neighbouring investments impact. The issue was discussed based on a pre-war building located in the Praga Północ District in Warsaw.