A shortage of well-designed family homes could undermine the government's plans to revitalize the UK's inner cities, a report has warned.
Manchester was among areas studied for the report
The Joseph Rowntree Foundation found developers were more keen on building flats, making it harder for schools and services to improve.
The think tank's report looked at four mixed income new communities (MINCs) in London, Glasgow and Manchester.
It said MINCs must attract better-off families to reach their renewal goals.
The researchers, from the Institute of Education and London School of Economics, found that these families were attracted to MINCs by safe, clean neighbourhoods with open spaces for children to play in.
They said the areas needed to attract these families to achieve their renewal goals and be sustainable in the long term.
The foundation also said the communities needed to be able to give couples without children the chance to stay where they were when they started a family.
But it found developers were often failing to build sufficient numbers of family homes for private ownership, or the homes were poorly designed or too small.