Bio-based building materials offer wide range of outlooks, starting from traditional rustic to modern
design products. Recent development in materials science significantly improve their functional performance. However, when considering use of bio-materials in outdoor environment, materials will deteriorate due to several processes: weathering, oxidation, biodegradation, wear or decay. In consequence biomaterials may loss visual appeal leading to a perceived need for replacement even if the material is far from reaching functional failure.
Visual assessment is the most direct method for evaluation of the aesthetics appearance of materials. However, it possesses high degree of subjectivity while performed by a not trained person. On the contrary, measurement of surface properties with dedicated sensors provides objective values that might be related to the current state of the material in use. Recent developments in field of optics and electronics open new possibility to perform measurements directly in-situ. Colour-, gloss-meters or spectrophotometers allows non-destructive measurements without particular sample preparation. Since all of above techniques provides complementary information the multi-sensor approach is more frequently suggested for applied research. The material state can be assessed regularly during service life. In this case such measurement turns into monitoring. The paper illustrates examples of assessment and monitoring of biomaterials degradation due to weathering. Direct implementation of various sensors is demonstrated. A proposal for the approach of combining data provided by various sensing techniques with data mining is also presented.