He told Building that he had been "mulling over" his departure from Bovis for some months. "I wanted to find a role that would be most useful to the company, and for me," he said.
He added that the move would give him the chance to devote more time to his hobbies, which include reading, opera and travelling.
His consultancy role will include advising on strategic issues and maintaining client relationships. Lampl said his future relationship with Bovis would be loose. He noted: "If we had made a strict agreement I don't think I would have done it."
Lampl took more of a back-seat role in the firm last July, moving from chairman to president. He first became chairman in 1985, and was instrumental in turning the firm from a UK-centred contractor into one of the world's top 10 construction companies.
David Higgins, Lend Lease's worldwide managing director, praised Lampl's contribution to the growth of Bovis. He said:
"Sir Frank has played a pivotal role in the successful transition of Bovis into the wider Lend Lease group.
"We wish Sir Frank well in his retirement and we are delighted that he will continue his association with Bovis Lend Lease."