 His church building St. Wendel, Frankfurt (1957) has been compared to Le Corbusier in terms of materials and flow of light.In 1962 he built the Klaus-von-der-Flüe Friedenskirche in Wörsdorf.In 1965 Krahn created a variation on the interplay of stonemasonry, glass and concrete of St. Wendel in St. Martin, Idstein.