Sustainable insulation of historical wooden and stone buildings with lime-hemp
In this multidisciplinary project lime-hemp is studied as a thermal insulating material for the renovation of historic timber and brick buildings*). Focus is on buildings in the historic city of Visby on the Swedish island of Gotland in the Baltic sea. Many historic buildings in Visby have over the past decades been thermally insulated with materials such as mineral wools and polystyrene. Due to this, damage caused by moisture and microbial growth has increased. As a consequence, cultural and historical values have been damaged. Lime-hemp is a sustainable building material that consists of hemp shiv and building limes. It works differently than conventional insulating materials; in addition to good thermal insulation properties, it also has good thermal mass and moisture buffering capacity. This project will study the durability of the lime-hemp, especially microbial growth and moisture problems, and opportunities for renovation of historic buildings, while creating a good indoor climate and preserving historical values. Labstudies as well as full-scale studies are conducted. The aim of the project is to sustainably improve energy efficiency while preserving historical values, without durability problems. *) The project started in September 2016 and results are not expected until earliest autumn 2017. The article will therefore give an outline of the project and some preliminary findings.