Binder-stabilised glass-fibre preforms provide enhanced handling, shape retention, and dimensional stability during the manufacture of large-scale glass-fibre reinforced polymer (GFRP) structures prior to resin infusion. Despite these advantages, producing high-quality and repeatable preforms remains challenging because the final preform architecture is strongly influenced by time-dependent deformation and the quality of cohesion at inter-ply and inter-bundle interfaces developed during preforming. Typical processing routes involve fibre stacks being compacted either to a prescribed thickness or via application of vacuum. During preforming, the compaction is frequently carried out at elevated temperature to activate the binder and promote stabilisation, followed by a dwell period to allow consolidation [1]. During this dwell, the preform exhibits viscoelastic creep and stress relaxation, which drives gradual changes in thickness, fibre volume fraction (Vf), nesting between yarn layers. These directly affect permeability and resin flow during infusion by dictating flow paths to saturate the dry preform [2]. A further source of complexity arises from heterogeneity in local binder content and distribution [3], which leads to spatially varying interfacial bonding strength throughout the preform. This study investigates the coupled influence of thermo-mechanical loading conditions on the compaction response of binder-stabilised GFRP preforms. A series of experimental trials is conducted to quantify how temperature and processing windows affect creep and stress relaxation kinetics, the resulting Vf and thickness stability, and the evolution of fibre-bundle architecture across different stages of loading, holding and unloading. The relationship between binder stabilisation, interface cohesion, and the observed loading–unloading behaviour from experimental trials is modelled using a state-of-the-art viscoelastic framework proposed by [4]. Emphasis is placed on calibration of visco-elasto-plastic material models capable of predicting bundle-level deformation. By linking manufacturing parameters and time-dependent compaction behaviour, this work provides guidance for robust preform design and improved repeatability in binder stabilised GFRP composite manufacturing.