Composite deck cost in Massachusetts runs $40 to $80 per square foot installed in 2026. A typical 300–400 square foot Trex or TimberTech deck costs about $15,000 to $32,000, including framing and railings, while premium lines like TimberTech AZEK reach $60 to $100+ per square foot. Most online estimates use warm-climate prices. Here, deck footings…