Exposure to sunlight, particularly to ultraviolet-A (UVA) radiation, can quickly change the appearance and surface quality of timber. This study examines how different wood species, surface orientations, and protective coatings influence discoloration in small glued-laminated timber (glulam) specimens. The intent is to better understand how to maintain the natural color and extend the service life of engineered wood products used in exposed or daylight-rich environments.
Test panels made from selected hardwood and softwood species were conditioned at 23 ± 2 degrees Celsius and exposed to controlled UVA radiation according to the procedures outlined in ASTM G154. Both coated and uncoated samples were placed edge-wise and face-wise to represent typical orientations found in construction. Surface color change (Delta E) was measured using spectrophotometric methods to compare the extent of discoloration among species, orientations, and coating treatments.
Previous studies on maple and bamboo have shown that species composition and surface treatments play key roles in how natural materials react to prolonged ultraviolet exposure. Building on this foundation, the present work investigates material and coating combinations that offer greater resistance to color fading. The findings will help guide design and material decisions for glulam applications where durability and visual consistency are critical.