Extension planning approval in Cardiff
Based on decisions in the last 5 years, as of 2 Jul 2026.
Of 327 extension planning applications decided by Cardiff in the last 5 years, 97% were approved. This is the council's track record for this kind of work. It is a useful gauge before you apply, not a guarantee for any one application.
Other work in Cardiff
- Rear extension : 97% approved (222 decided)
- Loft conversion : 94% approved (102 decided)
- Side extension : 96% approved (89 decided)
- Demolition : 96% approved (70 decided)
- Change of use : 94% approved (65 decided)
- Two-storey extension : 98% approved (41 decided)
Method
Approval rate = approved ÷ (approved + refused) over the public planning decisions we hold for Cardiff, matched to a type of work from the application description. We lead with the last few years so the figure reflects how Cardiff decides today, with the longer record as context. A rate is only shown once there are enough decided applications for it to be reliable. We publish aggregate figures only, never an individual application or applicant name. Read the full method and limits.