Mistakes that make applications invalid or delayed
A planning application can't move to determination until it's valid. Local authority pages often explain that missing fee or information prevents validation and registration.
Common 'invalid' triggers that stop your application in its tracks:
- Wrong application form/type (householder vs full vs prior approval)
- Missing location/site plan
- Missing supporting documents the council expects
- Fee not paid or incorrect fee (fees vary by type and rise annually)
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Try it nowMistakes that cause planning refusal
Refusals are usually about policy conflict and adverse impacts. The NPPF states that planning law requires applications to be determined in accordance with the development plan unless material considerations indicate otherwise.
Key drivers of refusal:
- Ignoring the development plan context—if your proposal conflicts with local policies on design, amenity, parking, heritage, or countryside, you need either revisions or a clear justification
- Underestimating neighbour amenity impacts—neighbour consultation is a formal part of the process; comments that raise material planning matters (privacy, overbearing effect, light, noise) can influence officer assessment
- Misusing permitted development assumptions—permitted development rights vary by property type and location and can be restricted on designated land; Article 4 directions can remove PD rights
How to reduce objection risk
Pre-empt neighbour concerns: show elevations, window positions, boundary distances, and any mitigation (screening, obscure glazing, stepped design).
Use the planning register to see what has been approved/refused nearby and why—councils publish plans and decisions.
Design to policy: the closer your proposal aligns with local design guidance, the less discretionary risk remains.
Want to stress-test your application before submission?
PlanWiser's Mock Application tool gives you an AI-powered assessment with approval likelihood, policy compliance analysis, and suggestions to strengthen your case.
Try it nowCommon expensive mistakes
These mistakes cost applicants time, money, and sometimes the project:
- Submitting without checking constraints first—Article 4, designations, and previous conditions can change the whole approach
- Skipping pre-application advice on borderline sites—typically £200–£600 and can save months of rework
- Assuming neighbour objections don't matter—they do when they raise material planning issues
- Using vague or inconsistent drawings—officers need clear plans to assess impacts
Check constraints and planning history before you apply.
PlanWiser's Property Checker shows designations, Article 4 directions, and planning history for any UK address in seconds.
Try it nowReal-world costs and timelines
Planning fees: A typical householder application costs around £258; full planning for a new dwelling costs £578 per unit (subject to annual indexation from April 2025).
Pre-application advice: Expect £200–£600 for written feedback from most councils.
Professional help: Planning consultants typically charge £1,500–£5,000+ depending on complexity.
Decision times: Most applications are decided within 8 weeks (13 weeks for unusually large/complex).
Step-by-step: what to do next
Follow this checklist to avoid refusal:
- Check planning history and constraints (designations, Article 4, previous conditions) using PlanWiser's Property Checker
- Choose the correct route: PD, prior approval, householder, full, etc.
- Build a clean submission pack: location plan, site plan, elevations, short planning statement linking to policy
- Validate assumptions with an LDC where appropriate
- Use PlanWiser's Planning Advisor and Mock Application tools to test your approach before submission