Yes, but coordinate with neighbors and HOA. Walls between units typically have STC (sound) requirements that closed-cell foam helps meet. Get HOA approval; some condos restrict foam due to fire-code interpretation.
More detail
Multifamily foam considerations. (1) HOA approval: required for any work that affects shared structural elements (party walls, building envelope, roof). Submit a written proposal listing the foam product, R-value, applicable thermal-barrier compliance, and a copy of the local installer's credentials. Most Cincinnati HOAs approve foam upgrades when the documentation is clear. (2) Fire-code: party walls between units have specific UL-listed assembly requirements; foam can fit into approved assemblies but only with verified thermal-barrier coverage. (3) Sound (STC) ratings: open-cell foam in party walls helps meet STC requirements (typically STC 50 minimum for newer condo construction). (4) Disturbance: spray-day work creates noise (compressors, sprayers) and odor that affects neighbors; coordinate timing in advance. Cincinnati condo and townhome stock generally allows foam upgrades when the HOA process is followed. Detached single-family within HOA-governed neighborhoods (some Mason, West Chester, Liberty Township subdivisions) usually require less coordination. Cincinnati condo-association coordination: most older Cincinnati condo associations require board approval for any work that affects shared structural elements, including foam upgrades on party walls or attic spaces. Submit the foam-product spec sheet, R-value documentation, and Cincinnati-area installer credentials with the request. Approval typically takes 30-60 days. Smaller condo buildings (under 12 units) often have simpler approval processes than larger complexes.