The foundation type is determined by site geological conditions and load-bearing requirements. Options include independent foundations, strip foundations, and pile foundations (for soft soil layers).

Excavate foundation pits 100-200mm larger than foundation size (depth 0.5-1.5m). Pour concrete cushion (100mm thick, C15 grade). After curing (≥70% strength), install reinforcement (HRB400 grade steel), formwork, and pour foundation concrete (C30-C35 grade) with proper curing (≥7 days).

Install foundation embedded parts (steel plates, anchor bolts) with precise positioning: ±2mm plane position, ±1mm elevation deviation. Anchor bolt verticality ≤1/1000, top elevation ±2mm. Ensure reliable connection to foundation reinforcement.

Position crane and use specialized spreader for stable lifting. Adjust module to ≤2mm/m levelness and ≤1.5mm/m verticality. Connect modules with high-strength bolts (200-300N*m torque). Weld or bolt to foundation embedded parts with quality control.

Install temporary hoisting bracket on lower module. Clean connection surfaces before lifting upper module. Align corner pieces precisely and connect with high-strength bolts. Install expanded space components (terraces, canopies) simultaneously.

Install lightweight insulated composite panels (50-100mm rock wool sandwich panels) with tongue-and-grove joints and sealing strips. Roof panels fixed with self-tapping screws (300-400mm spacing) and waterproof gaskets. Apply waterproof rolls and sealants at lap joints.

Check opening dimensions and clean debris. Secure frames with expansion bolts/nails. Fill gaps with foam rubber and seal with weatherproof sealant for flexible operation and optimal sealing.

Install prefabricated steel stairs (30°-45° slope, ≤2mm/m levelness) with proper corrosion protection. Railings (1.05-1.2m height, ≤110mm vertical spacing) welded/bolted to structure with corrosion treatment.