PROS

• Whirlwind fast on-site construction.
  
• Factory quality control.
  
• Certainty of price.
  
• Bespoke designs, with a variety of styles and materials available.
  
• High performance of energy efficiency, with impressive levels of insulation and double or triple glazing as standard.
  
• No hiring – and maybe firing – of builders.
  
• No drying time.
  
• Healthy buildings with non-toxic materials and 'breathing' membranes.
  
• Immune to skills shortage for the building trades.

CONS

• No tweaking the look once you have settled on your design.
  
• It’s hard to mix materials in prefab.
  
• Not the cheapest option for the self-builder. Prefab is subject to the economics of scale.
  
• Not ideal for small sites.
  
• Prefab still carries a low-quality stigma for some, which may affect insurance, mortgage and saleability.