Braintree-based John M. Corcoran and Co. will break ground at the end of the month on an $18.2 million, 72-unit addition to a Weymouth apartment complex, The Commons At South Field.

The first phase of the $60-million, 226-unit development was completed last year. Construction on the second phase is due to be completed in summer 2014.

"We are excited to begin the second phase of development at The Commons at SouthField Highlands," Richard J. High, president of John M. Corcoran and Co., said in a statement.

The new development features a roof deck, a WiFi Café with outdoor patio, a saltwater swimming pool, fitness center and game room.