Building safety backlog grows as new levy prepares to make developers pay for remediation

The latest figures show that 4,697 residential buildings of 11 metres and over were being monitored for unsafe cladding at the end of July, up from 4,191 at the end of January. This represents an increase of 12.1% in just seven months, highlighting the continuing scale of the remediation task despite years of work to identify and address unsafe buildings. Part of this increase reflects more of the buildings already expected to need work being brought into government programmes. MHCLG now estimates it is monitoring 64–81% of the buildings it expects to be remediated, up from 49–73% in January. 

The increase has been seen across both mid-rise and high-rise buildings. The number of buildings between 11 and 18 metres being monitored has increased by 13.7%, while the number of buildings measuring 18 metres and above is up by 10.8%. 

There has also been progress among buildings that have moved beyond monitoring and into the remediation process. The number of buildings where remediation is underway has increased by 3.3% since January, while the number where remediation has been completed has risen by 22.2% (including buildings still awaiting building control sign-off). The number of buildings waiting for remediation to commence has also increased by 7.5%, demonstrating that even as more projects reach completion, a significant pipeline of work remains. 

Every remediation project comes with a significant financial cost, and one of the central questions throughout the building safety crisis has been who should ultimately pay for putting unsafe buildings right. 

Introducing the Building Safety Levy 

From 1st October 2026, the Building Safety Levy will introduce a new charge on qualifying residential development in England, with the money raised intended to contribute towards the cost of remediating building safety defects on older buildings, including those where a developer cannot be held responsible or identified. The levy will apply to relevant building control applications and notices submitted from 1st October, with the charge generally applying to developments creating 10 or more dwellings or 30 or more purpose-built student accommodation bedspaces, subject to exemptions.* 

The levy will be calculated according to the chargeable floorspace of a development, with different rates set for each local authority area. The amount payable varies according to location and whether or not the development is on previously developed land. 

Kensington & Chelsea has the highest levy rate, at £50.17 per square metre for residential development on previously developed land, and £100.35 per square metre on previously undeveloped land. Westminster follows at £49.01 and £98.01 respectively, while Hammersmith & Fulham has rates of £45.94 and £91.87 per square metre.* 

Outside London, Epsom and Ewell have the highest rate at £56.62 per square metre for previously undeveloped land, followed by Cambridge at £50.87 per square metre. 

The introduction of the levy represents an important shift in how the cost of historic building safety defects is funded, but the scale of the remediation backlog means that funding is only one part of the challenge. The industry must also have the capacity to assess buildings, carry out remediation works, and secure the necessary approvals and sign-off once those works are complete. 

Sián Hemming-Metcalfe, Operations Director at Property Inspect, commented: 

“The Building Safety Levy marks an important step in addressing one of the biggest challenges to emerge from the building safety crisis, because it creates a dedicated mechanism for the development sector to contribute towards the cost of putting unsafe buildings right. 

However, money alone will not clear the backlog. The latest figures show that the number of buildings being monitored for remediation continues to grow, while thousands of buildings remain somewhere in the remediation pipeline. We need to make sure that the funding, skills, and capacity required to move these buildings through the process are available at the same time. 

Delays can arise at both ends of the process. Before remediation work on a high-rise building can begin, it needs approval from the Building Safety Regulator, and the latest BSR data shows remediation applications are taking a median of 33 weeks to approve. That's a significant improvement on the 43 weeks seen a year ago, but it still means many months can pass before work even starts. And one of the less visible challenges is what happens after the physical work has been completed. A building can have undergone significant works and still be waiting for the necessary inspections, evidence, and building control sign-off before residents can have full confidence that the process is complete. 

We are already seeing significant investment and reform aimed at addressing shortages in building control and other building safety professions. But the industry needs to keep building that capacity if we are going to turn completed works into fully signed-off, demonstrably safe buildings. The faster we can assess applications, verify completed works, and provide the necessary sign-off, the faster residents can have certainty that the work has been completed properly. 

The ultimate measure of success should not simply be how much money is raised or how many remediation projects are started. It should be how quickly buildings can move from being identified as unsafe, through assessment and remediation, to a point where the work is properly evidenced, signed off, and residents can move forward with confidence.” 

Data tables and sources

• *Building Safety Levy info sourced from the UK government

• *Building remediation data sourced from the UK government (1) and (2)

• *Levy rate information sourced from the UK government

• Full data tables can be viewed online here