The money was raised to refurbish an existing Victorian building in Hampstead with the final development consisting of 12 luxury apartments and two houses.
Cogress partnered with developer Paul Godfrey to complete the project, the third time that they had worked together on a venture.
The project is due to be completed by November 2018 with the development projected to sell for a combined £21.9m.
The expected range of the annual returns will be from 21.56% to 23.11%.
Cogress has enabled qualified backers to start with a £20,000 investment.
Tal Orly, CEO of Cogress UK, said: “The speed at which our community, of more than 3,000 qualified investors, funded the development illustrates the ongoing desire to invest in strategic and profitable investment opportunities.
“Despite initial industry fears over Brexit, our equity success here demonstrates that its business as usual for London’s property market.
“This success demonstrates the potency of our investor's appetite and confidence in Cogress to insulate them during uncertain market times.”