This paper examines the cost impacts of roof constructions of storage tanks, which are designed and built in accordance with EN 14015. After an introduction about the origin of the EN14015 and related standards, the technical content of those standards will be discussed, and appropriate solutions will be developed. Afterwords 280 different tank roofs will be statically computed and evaluated using a pre-calculation cost model. The influence of the various technical choices on the project costs will be investigated. The result of this work is primarily for manufacturers who want to use a cost-effective design to get a benefit against their competitors.