Oakwood, a new living area for those in the advanced stages of dementia, is the latest stage in the redevelopment of Manchester welfare charity The Fed's Heathlands site.
The facility, opened by charity vice-chaiman David Eventhall, increases Heathlands' mental health nursing capacity from nine to 12, in line with the rising need for specialist dementia care.
Mr Eventhall and The Fed's chief executive, Karen Phillips, planted an oak sapling in the adjoining wooded area.
"For me it summed up why I am involved in the Fed," he said. "To be part of the growth of an invaluable communal organisation and help build enduring services for the benefit of its members."
Chief operating officer Mark Cunningham added that clients would benefit "from living in smaller, domestic-style settings where they can be involved in household tasks such as meal preparation or folding laundry. This gives people a sense of purpose and identity and increases well-being and confidence."
The Fed spent £250,000 on the building work.