Expandify homes use 50mm-thick internal walls and 100mm-thick external walls, both made from rockwool-insulated sandwich panels.

Key features:

Internal walls: 50mm thick, with rockwool insulation (120kg/m3 density) and bamboo-finish internal panelling

External walls: 100mm thick, also using 120kg/m3 rockwool and finished with painted metal cladding

This structure provides excellent thermal and acoustic performance while keeping wall thickness to a minimum, allowing for more usable internal floor space.

There are no hollow cavity walls — all walls are solid, insulated, and fire-resistant as standard.