Below are the advantages and disadvantages of Expanding foams.

ADVANTAGES

• Provides thermal and acoustic Insulation
• Creates an air seal
• Easy to use and shape 
• Quick and simple
• Prevents moisture passing through, provided the outer skin is not damaged.
• Fills Holes/Gaps
• Can be painted
• Gorilla MS foam – Green Build option, isocyanate free foam

DISADVANTAGES

• Highly affected by UV 
• Difficult to remove once cured – only by mechanical means or Gorilla Expanding Foam Remover
• Need to fill voids by building layers
• Some Post Expansion (Soudal Expanding Foams are considered low post expansion foams)
• Propellants are high VOC, expect Gorilla MS Foam
• Low VOC only once cured – Not a product for Greenbuild Certification, except Gorilla MS Foam