LONDON—After the U.K.'s Heritage Lottery Fund denied a grant request from the Sir John Soane's Museum in June, trusts endowed by the late Simon Sainsbury and Paul Getty are donating money to the museum, Bloomberg reports.

The Sir John Soane's Museum was the house of its namesake, the architect of the original Bank of England building and a Royal Academy professor of architecture. Before he died in 1837, he specified that the house — a maze of rooms with lunettes, concave mirrors, and skylights that houses an Egyptian sarcophagus and works by Canaletto, among other treasures — should be kept open to the public for free.

The museum has drawn up a renovation plan that includes opening Soane's and his wife's bedrooms to the public and redoing the exhibition galleries. Staff offices will be moved to the building next door. In recent years, the museum received about £1.25 million ($2.49 million) from the U.K. lottery for purchasing the adjacent house and restoring the courtyards, as well as an additional £29,800 last August to help the museum create renovation plans.

But this year, the Heritage Lottery Fund rejected the Soane's £3.3 million grant request, and the museum has been forced to look elsewhere for funding. Sainsbury's Monument Trust has pledged £1 million, and the J. Paul Getty Charitable Trust has given £125,000.