Roof Alterations: When Do You Need Planning Permission? (2025)
Re-roofing, changing roof tiles, adding felt or insulation, and most roof repairs don’t need planning permission. But changing the roof shape, adding dormers, or altering a listed building’s roof is a different matter.
Quick Answer
Repairs and like-for-like re-roofing: no permission needed
Repairing a roof or replacing tiles like-for-like is maintenance and doesn’t require planning permission. Changing the roof covering to a different material (e.g. replacing concrete tiles with clay pantiles) is generally permitted development for most houses — but can be restricted in conservation areas by Article 4 Directions. Changing the roof shape (raising the ridge, converting a hip to a gable, adding a dormer) is development and may need planning permission depending on size and location. Rooflights are permitted development subject to size and projection limits. Listed buildings require consent for virtually any roof alteration.
Repairs and Maintenance
Routine roof maintenance and repair does not constitute development and does not need planning permission. This includes replacing broken or slipped tiles, re-felting or re-battening the roof, repairing or replacing flashings, repointing ridge tiles or chimney stacks, replacing guttering and fascias, and adding or replacing roof insulation.
Even a full re-roof using the same materials doesn’t need permission — it’s maintenance of the existing structure. The question becomes more complex when the materials change significantly (particularly in conservation areas) or when the work goes beyond maintaining the existing structure to altering it.
Changing the Roof Shape or Pitch
Altering the shape of a roof — raising the ridge height, converting a hip-end to a gable (hip-to-gable), changing the pitch, or raising eaves — constitutes development and requires planning permission unless it falls within permitted development limits.
A hip-to-gable conversion is development and is only permitted development on a detached or semi-detached house where it’s combined with a rear dormer extension under Part 1, Class B of the GPDO 2015, subject to volume limits (not exceeding 40m³ on a detached house or 20m³ on other types). Raising the ridge height or changing the overall profile of the roof in a way not covered by Part 1 Class B or Class C requires a full planning application.
Dormer Windows
Dormer windows are permitted development under Part 1, Class B of the GPDO 2015, subject to conditions:
| Condition | Detail |
|---|---|
| Position | Not on the principal elevation (front) of the house |
| Volume | No more than 40m³ on detached houses; 20m³ on semi-detached and terraced |
| Height | Must not exceed the existing roof ridge height |
| Setback | Must be set back at least 20cm from the eaves |
| Materials | Must be clad in materials that match or complement the house |
Front dormers (on the principal elevation facing the highway) are not permitted development and require planning permission. They are often refused in traditional residential streets unless the design is very carefully handled.
If a previous owner has already built a rear extension or other work that used some of the permitted development volume allowance (40m³ or 20m³), this reduces what remains for a dormer. The cumulative total of all roof alterations under Class B must stay within the limit.
Rooflights and Skylights
Installing rooflights (flat to the roof, e.g. Velux windows) is permitted development under Part 1, Class C of the GPDO 2015, provided the rooflight does not protrude more than 150mm above the existing roof plane, no part of the rooflight is higher than the highest part of the roof, and rooflights on the principal elevation more than 1.7m above floor level must be obscure-glazed.
A standard Velux-type window that sits flush with the roof slope will normally be permitted development without any application needed.
Conservation Areas and Listed Buildings
In conservation areas, Article 4 Directions often restrict changes to roof materials and coverings that would otherwise be permitted. Replacing natural slate with concrete tiles, or changing clay pantiles to interlocking concrete tiles, might need planning permission in a conservation area where the Article 4 covers roof alterations.
Additionally, in conservation areas, any extension or alteration that would be visible from a highway — including a rear dormer that can be seen from the street — requires planning permission. For listed buildings, virtually any alteration to the roof requires listed building consent — the roof is often a significant part of a listed building’s architectural character.
Your council’s conservation area appraisal will describe what materials and roof forms are characteristic of the area. Pre-application advice from the conservation officer is worth seeking before committing to any significant roof alteration.
Frequently Asked Questions
More on Permitted Development Rights
Extensions, loft conversions, outbuildings, solar panels — our complete guide covers everything you can build without planning permission.
