The rules mean properties can no longer be converted into what is classed as a house in multiple occupation (HMO) for up to six people without planning permission.
Mayor Chris Cooke and his Executive voted to back the change following concerns over an increase in HMOs, the standard of accommodation sometimes offered and the impact the properties can have on local areas.
The ‘Article Four’ direction, which came into effect on February 8, gives the Council the opportunity to consider plans from landlords and others and refuse permission where necessary.
Middlesbrough is the first local authority in the Tees Valley to bring in the change.
It covers the whole town except the area which is now governed by separate planning rules overseen by the Middlesbrough Development Corporation.
Mayor Cooke said: “It’s a real positive that the majority of Middlesbrough is now covered by this change.
“Obviously there is a need for single person accommodation, but we want to ensure people can live in affordable, good quality homes with appropriate space.
“In the past we’ve been powerless to act when that hasn’t been the case.
“From now on landlords wishing to convert what were family homes into lots of single rooms will have to apply for planning permission and stand up to scrutiny.
“Too many of the wrong sort of HMOs can change the fabric of the area and we need to uphold proper standards for the benefit of everyone.”
The policy contributes to the Council’s priority of supporting strong and resilient communities.
A HMO is defined as being a property occupied by at least three people who are not classed as being from the same household or family. HMOs generally offer several bedrooms and shared kitchen and bathroom facilities.
HMOs for seven people or more already require planning permission.
Separately to this month’s changes to planning requirements, all HMOs of five or more people are subject to mandatory licensing under separate legislation.