The conservation quango has dished out £325,000 in a bid to rescue 810 Tottenham High Road, a Georgian country house in the middle of one of London's most deprived areas.
The cash injection takes the total EH has spent on Tottenham High Road to £3.5 million, the largest amount of money it has invested in one single area.
The recipient of the latest handout, which is one of a pair of buildings, dates from 1715, when the Tottenham area was popular among the rich as a rural village in close proximity to London.
EH boss Simon Thurley emphasised that the history of the building's potential restoration had been troubled.
'I have visited this building many times,' he said, 'and until now it has always been to highlight the frustrating series of setbacks that have plagued attempts to restore and find a new use for it.
'Today I am delighted that the first major step has been taken to return it from a sad, neglected shell into a living building once again.
'Number 810, like its restored counterpart, number 808, is a rare, beautiful and important piece of London's heritage.
'The house tells the story of Tottenham's past - a country village where well-off merchants made their homes in the 18th century, a rapidly growing urban community gripped by industrialisation in the 19th century, followed by post-war economic depression and decline in the 20th.
'Importantly though, this building will now have a role in Tottenham's future and is something of which local people can feel justifiably proud,' he added.