The Government has proposed extending Class CB of Part 4 of the GPDO, the temporary permitted development right introduced for schools affected by reinforced autoclaved aerated concrete (RAAC).
Class CB currently operates until 24 October 2026. The proposal would extend that date by two years to 24 October 2028, while retaining the existing limitations and conditions. The consultation closed on 5 August 2026 and the extension has not yet been made.
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What is Class CB?
Class CB of Part 4 was introduced in October 2023 to help schools continue operating while RAAC-affected buildings are vacated, repaired or replaced.
The right allows temporary school buildings subject to detailed limitations and conditions.
What are the existing limits?
The current Class CB rules include:
- Temporary floorspace generally limited to 125% of the floorspace vacated because of RAAC
- No more than two storeys
- A maximum height of 9 metres
- No part of the temporary building within 5 metres of land in residential use
- No increase in the school’s published admission number
- Temporary buildings to be removed when the right no longer applies
The Department for Education says the right has supported more than 50 schools in England.
What would change?
Only the expiry date is proposed to change.
Government says not every school will have completed remediation before 24 October 2026, principally because of delays delivering replacement permanent accommodation and because a small number of RAAC-affected buildings were identified later.
The consultation therefore proposes keeping Class CB available until 24 October 2028.
Has Class CB already been extended?
No. The legal expiry date remains 24 October 2026 unless and until the GPDO is amended.
Our Class CB guide explains the current right, while Part 4 of the GPDO contains the other temporary building and temporary use rights.
Read the consultation
You can read the full MHCLG consultation on GOV.UK.
Published: 21st August 2026
