Performance of Excavated Finnish Clay in renderings under Finnish Cold-Climate Conditions : A Study of Four Traditional and Cross-Cultural Techniques
Ovitigamuwa Pathiranage, Thavisha (2026)
2026
Arkkitehdin tutkinto-ohjelma - Master's Programme in Architecture
Rakennetun ympäristön tiedekunta - Faculty of Built Environment
Hyväksymispäivämäärä
2026-05-27
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202605135575
https://urn.fi/URN:NBN:fi:tuni-202605135575
Tiivistelmä
The potential of exterior rendering applications based on clay for Finnish cold-climate architecture was explored in this thesis. The study focused on how to adapt and improve traditional clay plastering methods to increase the longevity of clay renderings in the harsh winter climate of Finland. Shrinkage, cracking, moisture behavior, freeze-thaw resistance, and breathable surface protection have received particular attention.
The topic was selected because of the significant volume of excavated clay produced by construction projects in Finland, as well as the growing interest in locally accessible and low-carbon building materials. Despite Finland's long tradition of using clay in construction, inadequate information exists about how clay renderings work over the long term in Nordic conditions.
The study included practice-based experiments, interviews with Finnish clay builders, precedent studies, and literature review. Utilizing locally accessible Finnish materials, four rendering systems that were influenced by traditional methods from Finland, Estonia, Sweden, and Japan were developed. From January to May 2026, eight test panels were built, subjected to outside winter conditions in Tampere, Finland and observed every week.
The outcomes demonstrated that rendering durability was enhanced by breathable surface treatments, flexible fiber-reinforced mixes, and wind-driven rain protection. Throughout the observation period, the Japanese Shikkui-based system and the Swedish cross-batten system demonstrated the most reliable performance.
The topic was selected because of the significant volume of excavated clay produced by construction projects in Finland, as well as the growing interest in locally accessible and low-carbon building materials. Despite Finland's long tradition of using clay in construction, inadequate information exists about how clay renderings work over the long term in Nordic conditions.
The study included practice-based experiments, interviews with Finnish clay builders, precedent studies, and literature review. Utilizing locally accessible Finnish materials, four rendering systems that were influenced by traditional methods from Finland, Estonia, Sweden, and Japan were developed. From January to May 2026, eight test panels were built, subjected to outside winter conditions in Tampere, Finland and observed every week.
The outcomes demonstrated that rendering durability was enhanced by breathable surface treatments, flexible fiber-reinforced mixes, and wind-driven rain protection. Throughout the observation period, the Japanese Shikkui-based system and the Swedish cross-batten system demonstrated the most reliable performance.