<p>Timber, as a kind of bio-based building material, will experience distinctive charring (pyrolysis) and combustion behavior under fire exposure. Thus, ensuring sufficient fire resistance is the primary concern on buildings using timber material. Apart from inherent char-layer fire protection, adopting transparent intumescent coatings is a promising approach of passive fire protection for timber structures. However, the related research in this field is still very limited, especially on the influence of transparent intumescent coatings under different fire exposure. In this study, a series of fire experiments were implemented to investigate the fire performance of glued laminated timber (GLT) protected with transparent intumescent coatings under ISO 834 standard and typical large-space fire exposure. Two different coatings including water-based coating and water-oil hybrid coating were developed and used. The experimental observations about key parameters of fire performance including time to ignition, temperature profiles and charring rate were presented. The influence of transparent intumescent coatings on the charring and combustion behavior of GLT under different fire exposure was clearly quantified. The research in this paper demonstrated that two transparent intumescent coatings are able to effectively delay the ignition time and reduce the charring rate under different fire exposure. Moreover, the influence of transparent intumescent coatings became more significant exposed to large-space fire. The maximum ratio of reduced average charring rate under large-space fire exposure was over 30%.</p>