North American Breweries has begun construction on its $2.6 million Brew House Project.
Company engineer Mark Minunni says workers knocked out windows and removed wooden planks from the ceiling and floor of 25 Cataract Street.
The work is in preparation for a museum, microbrewery, restaurant and souvenir shop.
Thirteen Cataract Street is currently undergoing asbestos removal before being torn down.
Earlier this month, the City Planning Commission rejected requests by preservation groups to designate the building as a landmark.
The Brew House is expected to open in August.