Glazed grid shell - Villers-Cotterêts castle
The Renaissance castle of Villers-Cotterêts has been designated by the French president to host the Cité internationale de la langue française. The renovation and transformation project, developed by Olivier Weets Architecte and studio projectiles, has been opened to the public in October 2023 after three years of construction work. Centrepiece and emblematic symbol of the castle is the fully glazed, free-form grid shell covering the interior courtyard. The cushion-shaped, 16x36m roof consists of a rhombic grid structure of custom-welded, single curved steel profiles glazed with 2x2m, diagonally curved insulating glass units. The geometry and tesselation have been form-found to be clad with thermally bent, single curved glass to reduce cost. The shallow rise of 1.3m combined with a low glass curvature of 25m, the structural node geometry, the irregular courtyard shape, the incapacity of the old masonry to absorb horizontal forces and rainwater drainage were key challenges to be met.