How Do I Avoid Planning Permission Refusal? 7 Common Mistakes

Planning permission can feel opaque: evolving policies, strict validation rules, and lots of moving parts (heritage, neighbours, trees, flood risk…). However, most refusals and long delays are avoidable. If you tackle these common pitfalls early, you’ll save weeks and give your design the best chance of first-time approval.

• Most householder applications aim to be decided in ~8 weeks after validation — understand what actually starts that clock and how to avoid resets: How long does a planning application take?
• Make sure you have the correct fee How much does a planning application cost?
• Many small projects can proceed under Permitted Development (PD); learn the boundaries before you apply: What is GPDO?

Image above by Luke, architectural designer on Design for Me. See his full profile and shortlist him for your home project here.

Why do applications often stumble?

Local planning authorities assess proposals against national and local policy and the site’s specifics (design, scale, heritage, amenity, highways, ecology and more). Refusals commonly stem from one of the following:

• Submitting the wrong application type or a package that fails validation.
• Misjudging Permitted Development vs planning permission.
• Underplaying heritage/designated land (conservation areas, listed buildings, AONBs).
• Missing supporting reports (flood risk, trees, heritage, etc.).
• Poor neighbour/amenity outcomes (overlooking, overshadowing, overbearing scale).
• Trying to change the scheme mid-determination without the right route.
• Ignoring conditions and expiry once permission is granted.

Mistake 1: Applying when you don’t need to, or assuming PD covers you when it doesn’t

What goes wrong
Two extremes cause problems: (1) You apply for planning when the work is eligible under Permitted Development (PD), wasting time and fees; or (2) you assume PD and start work, only to discover a rule, designation or previous extension removes/restricts PD.

How to avoid it

• Start with a basic understanding of permitted development: What is GPDO?
• For extensions, many schemes fall under PD – check limits, height, depth and neighbour consultation triggers: See Do you need planning permission for an extension?
• Common project types with clear guides:
  • Side return extensions  – often PD if you meet the rules: Do you need planning permission for a side return extension?
  • Garden rooms/outbuildings – size/height/siting rules and “incidental use”: See – Maximum garden room size without planning and Can I build an outhouse without planning permission? (2025)
  • Porches: Do I need planning permission for a porch?
  • Lofts: Do you need planning permission for a loft conversion?
  • Fences/walls: Do you need planning permission for a fence or wall? and How high can you build a wall without planning permission?
  • Conversions (what can change use without planning): What can you convert to a house without planning permission?
• Designations matter. In a conservation area or AONB, PD is often restricted. Check these first: Planning permission in a conservation area and Planning permission in an AONB.
• Don’t confuse planning permission with building regulations. Many PD projects still require Building Regs approval: What’s the difference between planning permission and building regulations?

Neighbour Consultation Scheme – larger home extensions (PD, England)
If you extend beyond the usual PD depth (up to 6 m terraced/semi or 8 m detached), you’ll trigger the prior approval process (often called the Neighbour Consultation Scheme) in England. Key points:

• The council consults neighbours for 21 days.
• The council has 42 days to issue a decision.
• As of 2025, the prior-approval fee for larger home extensions is £240 (England).

Details and examples: Do you need planning permission for an extension?

Pro tip: If you’re going the PD route, consider a Lawful Development Certificate for extra certainty when selling or insuring (see the PD articles above for context).

Mistake 2: Failing validation (wrong form, wrong drawings, missing certificates)

What goes wrong
The eight-week clock only starts after validation. Using the wrong form (e.g., Full Planning instead of Householder), submitting incomplete drawings, or skipping ownership certificates can cause invalid status and weeks of drift.

How to avoid it

• Match the application type to the project: most domestic works to a single dwelling use the Householder route; flats, changes of use or new dwellings often require Full.
• Follow a clear prep checklist: What do I need for planning permission?
• Drawings that typically pass validation: location plan, site/block plan, existing and proposed floor plans/elevations (to recognised scales), and roof plans/sections where relevant – see: Do you need drawings for planning permission?
• Don’t forget Ownership Certificates and serving notice where required (your local validation checklist explains exactly what’s needed).

Timing reality check: Validation itself can take a few days to a couple of weeks, depending on council workload and whether your package is complete. The 8-week target starts after this.

Pro tip: Professional presentation reduces queries. If you plan to DIY, use our drawing guide above; otherwise bring in expert help early (see Mistake 3).

Mistake 3: Underestimating design quality and neighbour impact

What goes wrong
Refusals often cite overbearing massing, loss of light/overshadowing, overlooking, or poor materials/detailing. Even if you “fit the numbers”, a scheme that harms neighbour amenity or lacks sensitivity with the site can be refused.

How to avoid it

• Sense-check scale and massing relative to your street and garden context.
• Anticipate overshadowing/overlooking concerns. Small adjustments to heights, window positions, or roof forms can be decisive.
• Talk to neighbours before submission; it can help inform sensitive design decisions, reduce objections and help your case officer.
• Consider professional design support from an architect. You’re not legally required to hire one, but it often pays for itself in time saved and stronger outcomes: Do I need an architect for a planning application?

Mistake 4: Skipping pre-application advice when your site is sensitive

What goes wrong
Submitting “cold” on a tricky site means the first meaningful feedback arrives during public consultation – when time is tight and objections are live.

How to avoid it

• Use pre-application advice to test ideas, confirm information requirements and gauge likely reaction, especially for heritage, tight urban sites or bigger moves. See: Should I pay for planning pre-application advice?
• Take the feedback seriously – revise drawings before you go live to consultation.

Mistake 5: Missing reports or proof for site constraints

What goes wrong
Applications near protected trees, in flood risk areas, or in conservation settings can be refused simply because the supporting evidence isn’t there.

How to avoid it

• Use your council’s validation checklist and what you learned at pre-app to scope reports early (e.g., tree constraints/ARB advice, drainage, ecological impact assessments, heritage statements).
• Revisit our heritage and PD articles for what’s commonly needed in conservation areas/AONBs:
  • Planning permission in a conservation area
  • Planning permission in an AONB
• If in doubt, your designer or planning consultant can advise exactly what to commission: Do I need an architect for a planning application?

Mistake 6: Trying to reshape the scheme mid-determination (or picking the wrong amendment route)

What goes wrong
Big design changes during determination can force re-consultation, increasing the 8 week target.

How to avoid it

• Keep in-determination tweaks genuinely minor. For modest post-approval changes, explore your amendment routes here: Can I change my planning permission?
  • Non-Material Amendments (s96A) — for very small changes.
  • Minor material changes via Section 73 — varies conditions and issues a fresh permission that sits alongside the original (you can only implement one version).
  • Important nuance: Section 73 can be used for permissions in conservation areas, but it cannot be used to vary a listed building consent (that has its own process).
• For meaningful redesigns, a fresh application is often cleaner (and faster) than trying to retrofit major change late in the process.

Mistake 7: Ignoring conditions, timings and expiry after approval

What goes wrong
Homeowners get their decision notice, then start on site without discharging pre-commencement conditions, or let permission expire assuming it can be extended.

How to avoid it

• Read every condition on your decision notice. If any are pre-commencement (materials, construction management, drainage, tree protection, etc.), apply to discharge them and wait for approval.
• Understand expiry and “keeping a permission alive”, including what counts as lawful commencement (e.g., foundation trenches as part of the permitted works, done in the right sequence). Start here: Can you extend planning permission?
• Plan your programme and budget, including the admin costs: How much does a planning application cost? (England, 2025).

Conservation areas: demolition wording (England)

If your project involves demolition in a conservation area in England, note the precise wording: separate “conservation area consent” no longer exists — you now need planning permission for relevant demolition in a conservation area (with familiar thresholds, e.g., buildings ≥ 115 m³ and certain walls/fences at 1 m/2 m). See our overview: Planning permission in a conservation area.

Also remember that Listed Building Consent is a separate consent from planning permission; unauthorised works to a listed building are a criminal offence.

A simple, refusal-proof process (step-by-step)

1. Establish your route
   Confirm PD vs planning permission and check for designations (conservation area/AONB). Read:
   • What is GPDO?
   • Planning permission in a conservation area
   • Planning permission in an AONB
2. Set expectations on time and cost
   Get realistic about validation, consultation and decision periods, plus fees.
   • How long does a planning application take?
   • How much does a planning application cost?
3. Assemble the right package
   Follow the validation checklist and submit clear, scaled drawings and the right forms:
   • What do I need for planning permission?
   • Do you need drawings for planning permission?
4. De-risk with pre-app (where helpful)
   If your site is sensitive, use pre-app to agree principles and identify the right supporting reports:
   • Should I pay for planning pre-application advice?
5. Submit and monitor
   Once validated, track progress and respond quickly to any queries. If you’re curious about how to view other local decisions for precedent/inspiration:
   • How to find a planning application
6. Decision and next steps
   If approved, read and discharge conditions in the correct order before starting work:
   • Can you extend planning permission?
   If refused, don’t panic. A targeted re-submission or the right amendment route can be faster than an appeal:
   • Can I change my planning permission?

FAQs

How long does a planning decision really take?
Councils aim for ~8 weeks after validation for most householder cases, but that goal assumes you’ve provided everything up front and there’s no need for re-consultation. Get the full picture here: How long does a planning application take?

Do I need an architect to apply?
No – but most refusals stem from weak drawings, policy blind spots, or poor neighbour outcomes. An architect or technologist can sharpen the proposal and shorten the journey: Do I need an architect for a planning application?

What does planning permission cost?
Beyond the application fee, budget for drawings, any supporting reports, and potentially condition discharge fees. See the current fee landscape: How much does a planning application cost? (England, 2025).

What if my project is in a conservation area or AONB?
Policies are tighter and design/heritage evidence carries more weight. Start with these guides and plan for higher-quality materials and detailing:
• Conservation areas
• AONBs

Is planning the same as building regs?
No – they’re entirely separate. Many PD projects still require Building Regulations approval: What’s the difference between planning permission and building regulations?

Can I alter my plans after approval?
Yes, within limits. For small tweaks, look at Non-Material Amendments; for minor material changes, a Section 73 application is the usual route. Bigger changes typically need a new application: Can I change my planning permission?

Need a hand?

The surest way to avoid refusal is a thoughtful, policy-aware design backed by the right documents, and a calm, tactical approach to the process. If you’d like expert help, Design for Me connects homeowners with the right residential architect or designer for their brief and budget.