In the UK since 2016 there has been a law that Councils hold a register of households wanting to self/custom build and to ensure that enough 'serviced plots' receive planning permission to meet that demand. The registered demand has been a fraction of what has been shown in opinion polling and even then the supply of plots has been derisory. At the same time we have millions of under-occupied homes owned by households who would downsize-in-place. So custom -splitting would be a way to accommodate more of the smaller households coming down the line and allow people to create their own home. The physical division of one into two does unfortunately require planning permission.
In the UK since 2016 there has been a law that Councils hold a register of households wanting to self/custom build and to ensure that enough 'serviced plots' receive planning permission to meet that demand. The registered demand has been a fraction of what has been shown in opinion polling and even then the supply of plots has been derisory. At the same time we have millions of under-occupied homes owned by households who would downsize-in-place. So custom -splitting would be a way to accommodate more of the smaller households coming down the line and allow people to create their own home. The physical division of one into two does unfortunately require planning permission.