The most common avoidable planning mistakes, and how to avoid them
Securing planning permission is one of the most important stages of any construction project. But new data obtained by Travis Perkins highlights how timelines can vary significantly across different parts of the country, depending on the complexity of applications and wider pressures on the system.
Data suggests that delays are not always down to the process itself, with avoidable issues within applications often contributing to longer decision times.
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Submitting incomplete or incorrect information
One of the most common reasons planning applications are delayed is because they are marked invalid at the point of submission.
Research from the Ministry of Housing, Communities and Local Government has found that insufficient or incorrect information is the leading cause of delays to planning applications, highlighting how avoidable administrative issues can significantly slow down the process.
Guidance from local planning authorities, including Cotswold District Council, also shows that applications are frequently held up due to missing documents, inaccurate plans or incomplete forms. Common issues include incorrect site location plans, missing ownership certificates and failing to include the correct supporting reports.
Even small administrative errors can cause delays. Missing a signature, submitting plans at the wrong scale or failing to include the correct fee can all prevent an application from being validated.
When an application is marked invalid, it cannot
progress until the required information is submitted, which can add weeks or even months to the process. In some cases, applications may need to be resubmitted entirely, restarting parts of the timeline.
Lee Jackson, Technical Director, Travis Perkins Managed Services at Travis Perkins, says, “Delays often start with relatively small issues at submission stage — missing documents, inconsistent drawings or incomplete supporting information. Taking the time to get the application pack right first time can prevent unnecessary delays further into the programme.”
Not aligning with local planning policies
Another common mistake is submitting proposals that do not fully consider local planning requirements or wider building regulations at an early enough stage.
Each council operates under its own planning policies, covering areas such as design, land use, environmental protection and infrastructure. Applications that conflict with these policies are more likely to be refused or require revisions, which can extend timelines and increase costs.
Industry guidance for small developers highlights that overlooking local policy requirements is one of the most frequent reasons schemes run into difficulty, particularly where proposals do not reflect local design standards or community considerations.
This is reflected in FOI findings, where some applications were rejected due to concerns around highways, landscape impact and ecology, showing how important it is to consider how a development fits within its surrounding area.
In some cases, this can also extend to the materials specified within an application, where elements such as bricks, external finishes or structural components like foundation blocks may need to align with local design and planning policies.
Failing to engage with neighbours and consultation early
Another issue that can delay planning applications is a lack of early engagement with neighbours and local stakeholders.
Once an application is submitted, it typically enters a consultation period where nearby residents and interested parties can raise objections or concerns. While not all objections will prevent approval, they can lead to requests for further information or changes to the proposal, which can slow down the decision process.
Planning guidance highlights that objections are usually considered based on specific factors such as:
• Loss of light or overshadowing
• Overlooking or loss of privacy
• Increased noise levels
• Traffic and access concerns
• The scale, height or design of the development
Jackson comments, “Engaging with neighbours early can help identify potential concerns before an application is submitted. Small changes to a design at an early stage can often prevent more significant issues later on.”
For developers and project teams, taking a proactive approach to consultation can help minimise objections and avoid delays once an application is under review. Understanding local sensitivities and addressing concerns upfront can lead to a smoother planning process and improve the chances of approval.
Applying for planning permission when permitted development would be enough
Another common mistake is applying for full planning permission when the work could fall under permitted development rights.
Government guidance highlights that many smaller projects, such as certain extensions, outbuildings and alterations, may not require full planning permission if they meet specific criteria. These permitted development rights allow work to go ahead without a formal application, provided limits and conditions are followed.
Submitting a full application unnecessarily can add time, cost and complexity to a project, particularly when the same outcome could be achieved through a simpler route.
However, confusion around what qualifies as permitted development means some teams take a more cautious approach and apply for planning permission regardless, which can slow down timelines.
Planning delays can have a significant impact on project timelines, but many of the most common issues are avoidable. FOI data gathered by Travis Perkins shows that while some applications can take months or even years to reach a decision, delays are often linked to incomplete submissions, misalignment with local policies or choosing the wrong application route.
Taking the time to prepare applications thoroughly, understand local requirements and address potential concerns early can help teams reduce the risk of delays and keep projects moving more efficiently.
