Within the market taxonomy, spray foam sealant is classified primarily by cell structure and chemistry. Open‑cell foam, representing about 55 % of volume, offers low density and superior vapor permeability, making it suitable for interior wall cavities and acoustic sealing. Closed‑cell foam, the remaining 45 %, provides higher compressive strength and moisture resistance, preferred for exterior sheathing, roof decks, and structural reinforcement. Sub‑categories further differentiate the products: low‑expansion variants (≤30 psi) target precise gap‑filling in HVAC ducts, while high‑expansion grades (≥60 psi) are deployed for rapid cavity fill in wall assemblies. Additionally, water‑based and solvent‑based chemistries address occupational‑health considerations; water‑based emulsions reduce volatile organic compounds, whereas solvent‑based systems deliver faster cure times in low‑temperature environments. The relative adoption of each type is governed by cost, performance requirements, and regional building codes, collectively shaping the total addressable market.