Radon reduction techniques for Finnish small houses

The general principles and design methods of developed radon gas reduction techniques for Finnish small houses are discussed. Most of these methods have been worked out since 1984 in the Laboratory of Structural Engineering and Building Physics at the Helsinki University of Technology in cooperation with the Ministry of the Environment, the Finnish Centre of Radiation and Nuclear Safety and private building material companies. This work has concerned basic research and some practical development projects concerning radon gas reduction methods for existing dwellings and new detached houses. The results have been very encouraging. As a result of this research, project reports and guidebooks have been published in which the developed reduction techniques are presented. Also a design method of groundbased structures based on radon classification of soil has been developed. This article is a review of the results achieved. (author)