ADACON UK

    Do Modular Buildings Need Planning Permission?

    It depends on how the building is used, how big it is, where it sits and how long it stays there. Many domestic garden rooms fall under permitted development, temporary buildings on construction sites are often covered by the site's existing consent, and commercial buildings in public or business settings usually need an application. Always confirm with your local planning authority before ordering.

    Adacon Technical Team · Published

    Domestic garden rooms and garden offices

    In many cases a single-storey outbuilding in a rear garden is permitted development, subject to conditions on height, proximity to boundaries, the proportion of garden covered, and whether the property is listed or in a designated area. Sleeping accommodation is normally treated differently from an office or gym.

    Construction site offices and welfare

    Temporary accommodation for the duration of construction work is frequently dealt with under the consent for the works themselves. Longer-term or public-facing installations are more likely to need their own permission.

    Commercial, education and leisure buildings

    Classrooms, clubhouses, cafés, retail units and permanent office buildings generally require a planning application, and may also engage building regulations depending on use and occupancy.

    Two-storey buildings

    A two-storey configuration is more likely to require permission than a single-storey one, because height and overlooking are material considerations.

    What we can help with

    We can supply dimensions, elevations and specification information for your application. We do not submit applications on your behalf and we do not give planning determinations — that decision rests with your local authority.

    Worth knowing: Planning rules differ across England, Wales, Scotland and Northern Ireland, and are affected by conservation areas, listed status, national parks and site history. Treat this as orientation, not a determination.

    Where to go next

    P300 / P400 / P600 range

    P300 unit
    2.9m × 2.2m externally; approximately 2.7m × 2.0m usable internally
    P400 unit
    3.9m × 2.2m externally; approximately 3.7m × 2.0m usable internally
    P600 unit
    5.9m × 2.2m externally; approximately 5.7m × 2.0m usable internally
    Configuration
    Mix P300, P400 and P600 units to create tailored footprints and shapes
    Unit height
    2.40m external / 2.16m internal
    Storeys
    Up to two storeys, subject to final project design
    Delivery
    UK mainland and Northern Ireland — transport quoted separately

    Adacon modular buildings use P300, P400 and P600 units with external lengths of 2.9m, 3.9m and 5.9m, a common 2.2m width and 2.40m external / 2.16m internal height. The sizes can be combined to create more tailored floor areas and building shapes, joined side by side or stacked to two storeys subject to the final project design.

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