Garden shed planning rules: Michel must act quickly after receiving a letter

A simple garden shed erected in a garden can raise planning issues. Michel must now act quickly, with supporting documents.

The letter Michel has received does not necessarily mean that his garden shed will have to be dismantled. However, he should not put it aside and wait. The structure’s actual size, local rules and the reply deadline stated in the letter will all carry significant weight as the process continues. Before responding, he should check the measurements again, review his local authority’s planning documents and gather accurate information.

The garden shed’s size could determine the outcome

For small garden structures, a few square metres can make all the difference. Planning rules are not always based on how large the shed appears to be. A cabin that looks modest may exceed the threshold set by planning regulations, particularly if it has a canopy, roof overhang or enclosed section added later.

Michel must first establish what the planning authority may take into account. Floor area relates to enclosed, covered spaces and is measured from the inside of the walls. Ground coverage, meanwhile, is the vertical projection of the structure’s volume onto the ground. A roof extending well beyond the walls may therefore matter, depending on the layout and local rules.

Before giving any reply, Michel would be well advised to measure the shed’s external length and width, record its height and photograph every elevation.

As a general rule, a very small garden shed may not require any formal planning process. Between certain thresholds, prior notification becomes necessary. Above those limits, planning permission may be required. The rules also differ in protected areas, near a listed historic monument, on certain designated sites, or in areas where the local development plan imposes particular restrictions.

What to measure without relying on the manufacturer’s label

The reference shown on an invoice or packaging is not always enough. A model advertised as being under 5 m² may have a different ground coverage once assembled, especially where it includes overhangs or an additional structure. Michel can draw up a simple dated record.

• The shed’s external length and width;
• The ridge height and wall height;
• Whether it has a floor, concrete slab or support pads;
• Roof overhangs, lean-tos and canopies;
• The distance between the shed, property boundaries and the house;
• The approximate installation date;
• Photographs showing the whole plot.

This information will allow the local authority to understand the actual position. It will also help Michel avoid an overly vague response that could delay consideration of his case.

Local planning rules go beyond national thresholds

The local development plan, often known in France as the PLU, sets out the rules that apply in each area of the municipality. It may regulate a shed’s height, external appearance, roof colour, position and the distance it must maintain from neighbouring land. A structure with a small floor area can therefore still cause difficulties if it stands in the wrong location.

Michel can visit the local authority’s planning department with his cadastral address, or at least his plot’s exact address. He can ask which zone his land falls within and which requirements apply to garden outbuildings. The written policy matters, but so do zoning plans and supporting appendices.

A shed that complies in terms of size may still be challenged if it is too close to a fence, too tall or located in an area subject to a special rule.

In some municipalities, for example, the rules require a structure to be built on the property boundary or, conversely, to be set back by a minimum distance. Others prohibit certain materials that can be seen from the street. Being close to a heritage area may also require consultation with an Architecte des Bâtiments de France, sometimes resulting in longer timescales.

What Michel can ask the planning department specifically

Simply asking whether the shed is “authorised” is not enough. A detailed enquiry will often produce a more useful answer. Michel can ask the planning reception team about the following points:

• The PLU zone that applies to his plot;
• The procedure required for his shed, based on its dimensions;
• Height and boundary-setback requirements;
• Restrictions connected with a protected site or particular designated area;
• Whether the situation can be regularised if a required procedure was missed.

A verbal discussion may guide Michel, but a written reply or submission receipt provides stronger evidence. He can also request a copy of the exact rule referred to in the letter he received.

Reply to the letter before the deadline, even if the file is incomplete

The most pressing issue remains the deadline shown in the letter. Michel should not wait until he has every answer before getting in touch. A brief, courteous and factual response shows that he is taking the request seriously. It can state that he is checking the shed’s dimensions and reviewing local planning rules.

He should retain a copy of the letter he sends, along with proof of submission or posting. If the local authority requests specific documents, such as a location plan, site plan or photographs, it is best to list them individually and indicate which items will be sent later.

Action to take	Practical purpose
Read the letter line by line	Identify the deadline, requested documents and reason for the inspection
Measure the shed	Check its area, height and actual ground coverage
Review the PLU	Understand the rules specific to the plot
Reply before the deadline	Prevent a lack of response from making the case more difficult
Keep every document	Maintain a clear record for any later correspondence

Regularisation may still be possible

If Michel finds that prior notification or permission should have been sought, the position is not necessarily final. An application to regularise the work may be possible if the shed complies with the applicable rules. The local authority will then assess the proposal as it would have done before the work began, while taking account of the fact that the structure is already in place.

If the shed breaches a rule on height, distance or appearance, alterations may be required. This could involve moving the structure, removing a canopy, changing the roof or reducing the enclosed section. Every case depends on the PLU and the precise wording of the letter.

Be aware of development tax

Another issue may arise where the shed exceeds 5 m² and reaches a sufficient height. Development tax applies to certain structures requiring authorisation. Its amount varies according to the area used for calculation and locally set rates. It is not a fine, but it may increase the cost of a regularised project.

Michel would therefore be wise to treat the letter as an administrative matter that needs resolving, rather than a simple observation. Reliable measurements, careful reading of the PLU and a timely reply will give him a sound basis to support his case or correct whatever needs to be corrected.