ePrivacy and GPDR Cookie Consent by Cookie Consent Amending planning permission: Can you make changes? | Resi

Amending planning permission: Changes you CAN and CAN'T make after approval

6 min read
Feb '26 • by Jodi Nicholls

Quick summary

After planning permission is granted, you can make small, non-material changes like adjusting windows or interiors without needing a new application, but major alterations such as enlarging your extension or moving structures require a fresh planning application or reapplication. Always check with your local authority to avoid costly breaches or refusals.

Before your home improvement hopes and dreams become a reality, you need to secure the green light, thumbs up, and go ahead at various stages. Whether it’s surveying, architectural drawings, planning approval, building regulations or sourcing contractors, it’s hard to know when changes to your design can and can’t be made.

The stage that often causes the greatest amount of confusion is the one after planning approval. You’re likely sorting out your building regulations and gearing up to start construction, but wait a minute, wouldn’t that window look better over there? Maybe a sliding door would work instead of a bi-fold? Could the kitchen work better if it was further to the back?

To better understand what’s possible, we asked our architects to break down your post-planning options.

How much can I change plans after planning permission is granted?

If you’re dying to change up your project’s design, we’re afraid to say you’re limited. Councils generally don’t allow major design changes; however, they do allow room for alterations that fall under ‘non-material amendments.’

Small changes under this banner might include:

  • Amendments to windows/doors/openings that don’t overlook neighbouring properties
  • Reducing the size of your building/extension
  • Changing your interior layout
  • Adding a patio no higher than 30cm

It’s important to note there’s no statutory definition of what falls under this category, so it’s often up to your local authority to make a subjective decision.

To help offer some clarity, we recommend talking through potential changes with your case officer or asking your architect to do this on your behalf. However, before you go down official channels, ask your officer for informal advice on the likelihood of your proposed changes being approved.

If you do decide to go ahead with your alterations, you’ll need to make a formal ‘non-material amendment’ application, which will incur a small fee.

Contents