This guide explains boundary rules affecting dormer extension projects in Tonbridge and Malling, Kent.
| Maximum Height | 4m pitched roof / 3m flat roof |
| Eaves Height | Maximum 2.5m |
| Boundary Rule | 2m distance required for full height |
| Coverage Limit | 50% of total land around house |
Understanding boundary rules is important when planning a dormer extension project in Tonbridge and Malling. National planning rules set limits on size, height and location of developments that may be built under permitted development rights.
Local planning policies, conservation areas and Article 4 directions may also affect whether planning permission is required.
Many developments fall under permitted development rights.
Yes, Article 4 directions can remove permitted development rights.
Yes, additional planning restrictions may apply.
Last updated March 2026