A useful design comment describes what would change and why that matters in this particular place. “I do not like the extension” gives the council little to assess. A clearer concern identifies a roof form, building proportion, material, street relationship or heritage feature, shows the proposed change and points to the relevant policy.
This guide concerns planning applications in England. It helps you prepare factual observations; it does not provide a professional heritage assessment or predict a decision.
What do design, character and street scene mean?
Design includes how a building is arranged and how its scale, shape, roof, openings, materials and details work together. Character concerns the features that make a place recognisable: perhaps repeated narrow plots, a varied roofline, consistent building heights, brickwork, gaps or a particular relationship between buildings and open space. The street scene is the way buildings and spaces are experienced along a street.
Start with what is actually there. A street may have a consistent pattern or considerable variety. Neither description should be assumed from one photograph.
Current national policy asks development to respond to its context, including history, character and heritage, while allowing appropriate innovation and change. It does not require every proposal to copy its neighbours. Read NPPF design policy DP3 alongside the applicable local policies.
Is “out of character” a planning argument?
It can describe a relevant concern, but it needs an explanation. Which characteristic matters, where is it evident, and how would the proposal affect it?
For example, you might identify a repeated roof form and explain how the proposed dormer would replace most of its visible slope. Give drawing references and a photograph showing the existing pattern. Avoid saying that every dormer is unacceptable, or that a different material is necessarily harmful.
Separate your preference from the planning effect. Disliking grey cladding is a preference. Explaining how a proposed cladding treatment would affect a documented architectural feature gives the council a specific issue to assess. The conclusion still depends on the proposal, evidence and policy.
A nearby permission may be useful context. Check its approved drawings, date and reasons before calling it comparable. A smaller dormer, a different elevation or a building outside the relevant conservation area may explain a different decision.
Scale, roof form, materials and visibility
Describe scale through the relationship between the addition and its host building or surroundings. Height alone may miss the effect of width, depth, roof shape or a change in building line. Distinguish measurements on current plans from estimates.
Matching materials can help a design fit, but they do not automatically resolve a disproportionate roof addition. Conversely, contemporary materials can be acceptable in an appropriate design and context. Our roof, dormer and extension evidence includes contrasting historical decisions.
Visibility helps explain an effect. Identify a lawful public viewpoint and what it shows. A rear alteration may be less prominent from the street without being irrelevant to the building's character or a heritage assessment. Do not treat a view from your garden as a protected private view.
If your concern is how a wall dominates a room or garden, explain that separately using the privacy, outlook and overbearing examples. A design criticism does not establish a harmful living-condition effect, or vice versa.
Conservation areas and listed buildings are different
A conservation-area designation concerns an area's special architectural or historic interest. A listed building is an individually designated heritage asset. An unlisted building can contribute to a conservation area's character; being in the area does not make every building individually listed.
For planning decisions involving listed buildings or their settings, section 66(1) requires special regard to the desirability of preserving the listed building, its setting or relevant special features. Section 72(1) requires special attention to preserving or enhancing character or appearance when the relevant planning functions concern buildings or land in a conservation area. These are distinct duties: see section 66 and section 72.
Conservation-area status does not automatically prevent extensions or alterations. Check the boundary and the relevant adopted appraisal. Identify the particular feature that the document describes and how the application might change it. Avoid assuming that every existing feature makes a positive contribution.
Use Historic England's official List to check listed status. A planning application affecting the setting of a nearby listed building is not itself a grant of listed-building consent. If more than one application is involved, check which proposal and consent your comment concerns.
Heritage significance and setting
Heritage significance means the value arising from an asset's archaeological, architectural, artistic or historic interest. It can arise from the asset and its setting. Setting is the surrounding context in which an asset is experienced; it is not a fixed-distance circle. See the national policy glossary.
A neighbour can identify an observable relationship, such as a proposed addition appearing beside a listed building from a particular viewpoint. That observation does not establish the building's significance or a level of heritage harm.
Read the application's heritage information. Does it identify the asset, explain relevant significance and address the part of the setting affected? Current heritage policies HE4–HE6 require proportionate consideration of significance and effects, including setting. An effect on significance is not determined simply by the size of the proposal. If information appears missing, identify the question rather than supplying an invented expert conclusion.
Historic England's setting guidance can help explain the concept. Its 2017 second edition is under review following national policy changes; use the current framework for current policy tests.
What does an Article 4 direction change?
An Article 4 direction can withdraw specified permitted-development rights within a defined scope. It can mean that a planning application is needed for work that would otherwise use those rights. It does not itself determine whether the application should be allowed: see official planning guidance, paragraphs 036–040.
Do not infer coverage from a conservation-area boundary. Check the council's current direction, map, affected development classes, properties and relevant dates. This guide makes no claim that a particular property is covered.
A practical evidence checklist
- Record the application reference, proposal description and latest drawing numbers/revisions. Keep existing and proposed elevations distinct.
- Note your location in relation to the proposal. Describe the affected elevation, roof or street section.
- Take your own dated context photographs from places you may lawfully use. Show enough of the surroundings to support the pattern you describe, rather than selecting only the nearest matching building.
- Identify recurring features: roof slopes, plot widths, building lines, proportions, materials or gaps. Explain any important variation too.
- Check the official conservation-area boundary and relevant appraisal. Note its title, adoption date and exact paragraph or page.
- If relevant, identify the official listed entry and the particular relationship with the proposal. Do not infer that everything nearby is listed.
- Read available design/access and heritage statements. Identify an apparent factual discrepancy by document and page; distinguish an unanswered question from a proved error.
- Match each concern to a relevant current policy and observable change. Ask the council to assess it; avoid predicting a harm classification.
Do not enter private land to gather evidence. Use your own photographs carefully, avoiding unnecessary people, interiors or identifying details. Refer to application drawings by number rather than copying third-party illustrations into public posts.
Turn observations into a clear comment
A fictional example: “The existing rear elevation drawing shows a continuous sloping roof above the extension. Proposed drawing P02 shows a dormer occupying most of that slope. My photograph A shows the same roof form repeated along this group. Please assess the change against the adopted design policy and the appraisal's discussion of this roofscape.”
Use that structure only where your documents support it. Do not invent an appraisal passage or a photograph. An honest qualification—such as not knowing the material behind an existing coating—is more useful than an unsupported assertion.
Keep property value, personal dislike and the applicant's motives out of the design argument. Explain amenity effects separately. See material planning considerations and how decisions weigh neighbour comments.
Use the right local documents and next step
Start with your council's adopted plan, relevant policy map and any applicable design guide or appraisal. The Islington resource and Kensington & Chelsea resource show different local starting points. Their policies do not apply elsewhere.
Use the application and evidence checklist to organise your notes. Check the comment-deadline guidance and the notice for your application rather than waiting for perfect photographs. The free eligibility check is a useful next step if you need help identifying the service route; pricing and toolkit details explain the paid option.
Sources and corrections
National policy references above are to the framework published on 17 August 2026. Sources checked for this guide: 26 October 2026. Historical appeal examples use the policies applicable to their decisions, not today's framework. If a source or sentence needs correction, contact us with the page and wording concerned. Explore related resources in the Planning Information Hub.