Assessment and Monitoring of Aesthetic Appearance of Building Biomaterials During the Service Life

Abstract

Bio-based building materials offer a wide range of outlooks, from traditional rustic to modern design products. Recent development in the science of materials significantly improves their functional performance. However, when considering the use of bio-materials in outdoor environments, materials will deteriorate due to processes like weathering, oxidation, biodegradation, wear, and decay. Consequentially, biomaterials may lose 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 aesthetic appearance of materials. However, it possesses a high degree of subjectivity when performed by an untrained 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 opens a new possibility to perform measurements in-situ. Colour-, gloss-, or spectro-photo-meters allow non-destructive measurements without particular sample preparation. Since all of the above techniques provide 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.

Visual appearance of unpainted wood: mould coverage, lightness and uniformity

“…When exposed to sunlight, varying moisture levels and fungi, wood changes colour and may check or crack (Evans 2012). Most of these changes are mainly surface phenomena, but as they affect the visual appearance, these changes can be crucial for the service life (Sandak and Sandak 2017). If unwanted aesthetic changes occur, a building component might be replaced even though it is not mechanically damaged or has reached the end of its technical service life.…”

“…(2015) proposed a multisensory approach to objectively evaluate surface weathering, and as illustrated by Sandak et al. (2017), evaluation of aesthetic attributes should include more than pure colour analysis, for example, surface criteria such as pattern, roughness and gloss. A uniform appearance of weathered wood is often desired, especially concerning colour.…”

Numerical investigation of mould growth risk in a timber-based facade system under current and future climate scenarios

“…The results show that there is a risk for mould growth due to the exterior climate and in particular the combination of air temperature, relative humidity and solar radiation [7,8]. Various models have been developed to predict the hygrothermal performance of wooden facades and claddings [9], while probabilistic-based methodologies have been suggested [10,11]. The surface treatment of the facade or cladding plays a central role for ensuring the durability of the material and consequently the resilience of the facade system and building.…”

Effect of a Thermal Catalyst on Organosilanes Treatment to Improve Durability and Stability of Canadian Wood

“…The service life of wood products used in exterior applications is based on both functional criteria, such as mechanical performance, and aesthetic criteria, such as checking, warping, or surface discoloration. It is often the aesthetic criteria that define the product's service life [1]. While maintaining resistance to biodegradation is essential for maintaining mechanical performance, different approaches are needed to extend aesthetic service life.…”