Work has begun at the former Ely Paper Mill, where there's been a £100m investment to create a housing development with up to 800 affordable homes.
The site, on the old Arjo Wiggins Teape paper mill on the banks of the Ely river, aims to address the shortage of affordable housing in Cardiff.
Around 60% of the homes will be available at below-market level rents.
Welsh building society, Principality, with a commercial loan from the Welsh Government, is behind the project.
The company says the site, which spreads over 53 acres, will be closely linked to a proposed primary school, existing health centre and community hospital.