Frost destruction of porous building materials is a big problem in the Scandinavian countries, and in many other countries inside and outside Europe, such as U.K., Germany, countries in eastem Europe, U.S.A., Canada, etc. Much research has been devoted to solving the frost destruction problem, especially conceming the destruction of concrete, but also conceming the destruction of clay brick, roofing tile, cellular concrete, natural stone, etc. Nordic researchers have made important contributions in the past; names such as Poul Nerenst in Denmark, Sven Gabriel Bergström and Birger Warris in Sweden, and Jukka Vuorinen in Finland can be mentioned. Previously, frost damage was in most cases of type internai damage occurring when the "stone" was frozen in a more than critically saturated condition. During the last decades, surface scaling of concrete is a growing problem in many countries. The reason is an increased use of deicing salts on roads and bridges. Maybe, surface scaling is a rising problem also for other mineral materials, such as natural stone and renderings. In this case, the reason might be that air pollution causes deposition of substances at the stone surface. Eventually, these interact with moisture and frost to cause surface scaling. The mechanisms behind internal frost damage is fairly weIl understood due to work done in the fourties, fifties and sixties, primarily in the U.S.A. by T.C Powers, R.A. Helmuth and others. The mechanisms behind surface salt scaling is however still largely unknown, But as can be seen in these proceedings, much work is now being done in order to clarify the salt scaling mechanism. A very important step has also been the development of salt scaling test methods, that can be used for a rationaI selection of durable concrete. The purpose of this Nordic research seminar was to get a general view of research going on in the Nordic countries on frost destruction. Naturally, most papers deal with concrete, but there are also some papers on other materials. Researchers from Finland, Denmark Norway and Sweden took part in the seminar. This seminar was the second in order. The first took part in 1993 with only a few participants. Hopefully, there will be a third seminar within a few years time summarizing all the frost research which is now going on in the Nordic countries, or that will start in the near future.