Steel-Frame vs Traditional Garden Rooms: Which is Better in 2025?

Steel-frame garden rooms (iFrame, Ultraframe) cost £38,000-£52,000 vs £28,000-£38,000 for traditional timber frames (4m x 3m room). Engineering advantages: spans up to 6m vs 3.5m for timber, 40+ year lifespan vs 20-30 years, 80% glass possible vs 60% maximum, zero dimensional movement. Steel enables larger bi-fold spans, cantilevers, green roofs (300kg/m²+), and contemporary minimal-frame designs. However, timber is "good enough" for 80% of projects. Choose steel for complex designs, large glass areas, or long-term investment. Choose timber for budget-conscious, traditional aesthetics, or standard rectangular rooms. Real Cobham, Virginia Water, and Weybridge case studies included.