21 Chemin de Roscaroc, 29830 Ploudalmézeau

Parcel of 2,805 m² (recorded area) with 1 building. Planning document zones: N and Uhb.

Recorded area: 2,805 m²
Planning zone: N (63%) · Uhb (37%)Straddles 2 planning document zones.

Address from France’s national address register (BAN), associated with this parcel for information only. Addresses and how they are linked

The parcel (in colour) and its neighbours, from the cadastre; computed perimeter: 320 m. North is up; the bar gives the scale.

The cadastre is a tax record: it does not prove ownership. Why?

The cadastre is a tax record: it does not prove ownership and its boundaries have no legal force (only a surveyor's boundary marking does). Its plan is approximate: especially where it is old, it can be offset by a few metres from the buildings and the aerial imagery. The owner's name is not shown. Boundary marking (Service Public, in French)

At a glance

Computed area: 2,893 m²from the cadastral plan
Perimeter: 320 mcomputed from the cadastral plan
Buildings: 1 building
Height to the eaves: 4.8 m
Addresses: 1 linked address
Clay soils: Low exposure (100% of the parcel)
Risk prevention plans: Not recorded

This parcel’s figures, from the cadastre, the national address base (BAN), IGN’s BD TOPO and the risk databases. Missing data is not shown.

What this means for a project

Zone N: new buildings are in principle excluded; a measured extension of an existing home may be allowed where the rules provide for it. Guide: Turn the map finding into a specific question
Zone Uhb: before an extension, a shed or a division, read this zone’s rules (height, footprint, setbacks from the street and the boundaries). Guide: Turn the map finding into a specific question
The parcel is split between 2 zones: each part follows the rules of its own zone. Guide: Read the documents, not just the colour
2 prescriptions, information areas or easements touch the parcel (details below): they apply on top of the zone’s rules. Guide: Read the documents, not just the colour
Radon potential category 3: it appears in the information given to buyers and tenants; ventilating and, during works, sealing between the ground and the building reduce exposure. Guide: Prepare the formal risk statement

Points drawn from this parcel’s data. They tell you which questions to ask; they do not replace a certificat d’urbanisme or the official statement of risks.

Understanding the map information

Planning zoning

N – Natural and forest zone (N)

Protected natural areas, forests and landscapes: building is strictly limited.

63% of the parcel
Document: 29178_PLU_20241121

Uhb – Urban zone (U)

Urban zone family. This category does not establish permission to build: check the local code, applicable rules and parcel constraints.

37% of the parcel
Document: 29178_PLU_20241121

Addresses

Source: Base Adresse Nationale (national address register). “Linked by its position”: the address point lies inside the parcel. “Linked by its building (RNB)”: the building that carries the address in the national building register (Référentiel National des Bâtiments) stands on the parcel. “Linked by IGN (BAN PLUS)”: IGN matches the address to this parcel, the nearest one on the same side of the street, and the address point lies inside it. In these cases the Base Adresse Nationale declares no link.

21 Chemin de Roscaroc, 29830 Ploudalmézeau

All addresses in Ploudalmézeau

Local plan prescriptions

For guidance only, from the Géoportail de l'Urbanisme extraction of 15 August 2026; the linked document may have been replaced since. Only the planning document's regulations and annexes are binding. A missing item means “not recorded”, not “no constraint”.

National clay exposure (BRGM/Géorisques) and labels in the local planning document are separate sources: dates, methods and purposes may differ. Both values are retained; neither replaces the other. Check the national map and local rules with the authorities. Data versions: national clay layer 2026-07-02; GPU extraction 2026-08-15. Géorisques: soil studies and construction

Not recorded in the Géoportail de l'Urbanisme

Local plan information

Development tax sector: Secteur sousmis à la taxe d'aménagement au taux de 3% – 100% of the parcel
Urban pre-emption right: Droit de préemption urbain – 37% of the parcel

See the document on the Géoportail de l'Urbanisme

Public-utility easements

Not recorded in the Géoportail de l'Urbanisme

Buildings

Indicative data (IGN BD TOPO): buildings IGN links to the parcel (BAN PLUS) when they cover at least 20 m² of it, with information from the tax files (DGFiP), anonymised. An unknown height or number is not shown. Construction years are grouped into periods, because old buildings often carry an estimated round year (1800, 1900…). A building standing on several parcels is counted on each, with all its dwellings. Recent buildings may be missing: the tax files are updated with a delay.

On the parcel: 1 building
Height to the eaves: 4.8 m

Risks

This information is for guidance only and has no regulatory force: it does not replace the risk statement (état des risques, ERRIAL) to be attached to a sale or a rental, which anyone can produce free of charge on Géorisques.

Some clay soils swell when wet and shrink as they dry, which can crack buildings. The higher the exposure, the more building precautions are needed. A risk prevention plan (PPR) maps the areas exposed to a hazard (flooding, ground movement, an industrial site…) and sets building rules there. The Géoportail de l'Urbanisme does not list every plan yet.

Clay shrink-swell: Low exposure (100% of the parcel)
Risk prevention plan: Not recorded in the Géoportail de l'Urbanisme
Seismic zone: Zone 2 (low)
Radon potential: Category 3 (significant)

Produce the risk statement (ERRIAL) on Géorisques Risks near an address (Géorisques)

The parcel in its section

By recorded area, larger than 86% of the 559 parcels of section ZC whose area is recorded.
Median recorded area in the section: 835 m².
258 of the section’s 559 parcels have a linked building, 355 an address.
Ploudalmézeau has 9,606 parcels; this one holds 0.01% of their total recorded area.

Details

Cadastral reference: 29178 000 ZC 649 (29178000ZC0649)
Commune: Ploudalmézeau (29178)
Prefix: 000
Section: ZC
Number: 649
Recorded area (contenance): 2,805 m²
Computed area: 2,893 m² Computed from the plan, may differ from the recorded area.

Planning in this commune

Planning document: Local zoning plan (PLU) (29178_PLU_20241121)

Find the applicable document on the official GPU map

Document identified in the data, without assurance that it covers the whole commune or every parcel. Several documents may apply. Check coverage and the current version with the town hall or GPU. For guidance only, from the Géoportail de l'Urbanisme extraction of 15 August 2026; the linked document may have been replaced since. Only the planning document's regulations and annexes are binding. A missing item means “not recorded”, not “no constraint”.

Planning zones (share of parcel area):

Agricultural zone (A) (61%)
Natural and forest zone (N) (19%)
Urban zone (U) (18%)
Development zone (AUc) (2%)
Closed development zone (AUs) (0%)

Source datasets used on this page: 8. Their dates and reuse terms can differ.

Sources and versions used on this page

Plan cadastral informatisé (Etalab) 2026-06-01 — Licence Ouverte / Open Licence 2.0
Cadastre Etalab redistributes the French digital cadastral plan in simplified geographic formats, including parcels, sections and buildings. Mapped boundaries do not replace a boundary survey.
Géoportail de l’Urbanisme — extraction nationale 2026-08-15 — Licence Ouverte / Open Licence 2.0
The national Urban Planning Geoportal extraction brings together layers published by the GPU from documents supplied by municipalities, intermunicipal authorities and state services. The competent authorities remain responsible for the documents and their regulatory meaning.
Base Adresse Nationale (listes d’adresses et géocodage Géoplateforme) 2026-10-07 — Licence Ouverte / Open Licence 2.0
The Base Adresse Nationale brings together French addresses, including those published by municipalities. Address coordinates alone do not establish an administrative link to a cadastral parcel.
BAN PLUS (rattachement géométrique adresse → parcelle) 2026-06-15 — Licence Ouverte / Open Licence 2.0
BAN PLUS is IGN’s product linking Base Adresse Nationale addresses to reference geographic objects, including cadastral parcels, using geometric matching.
Exposition au retrait-gonflement des argiles 2026-07-02 — Licence Ouverte / Open Licence 2.0
The clay shrink-swell exposure map describes geological exposure at the map’s scale. It does not replace a site-specific geotechnical investigation.
Zonage sismique de la France (décret n° 2010-1255), liste version janvier 2015 2018-07-30 — Licence Ouverte / Open Licence 1.0
This vector layer published by wpd is based on the BRGM / planseisme.fr list of municipalities and seismic zones, January 2015 version. Municipal zoning does not measure the structural risk of an individual building.
Potentiel radon des communes (arrêté du 27 juin 2018) 2019-05-06 — Licence Ouverte / Open Licence 1.0
Radon potential zoning classifies municipalities according to their geological potential to emit radon. It does not measure the indoor radon concentration of an individual building.
BD TOPO® – bâtiments (usage, hauteur, niveaux, logements, année de construction) 2026-06-15 — Licence Ouverte / Open Licence 2.0
BD TOPO is IGN’s vector topographic reference dataset. Its building component describes footprints and available attributes such as use, height and selected construction information.