What is plinth extension?

Plinth extension is the enlarging or repurposing of a building’s plinth: the ground floor, which in many residential blocks is not used for living. In Dutch it is called ‘uitplinten’, from ‘plint’, the word for the ground-floor zone of a building. The term comes from Dutch housing renovation and is used, among others, by the knowledge network Platform31. English has no fixed equivalent; ground-floor conversion or activation describes the same idea.

Background

Many Dutch gallery-access and walk-up blocks from the post-war period have a ground floor filled with storage units, garages, entrances and plant rooms. Comparable blocks exist in other countries. With plinth extension that layer is enlarged, rearranged or converted into living space.

Why do it?

• More storage needed: after topping up a building, the new flats also need storage space.
• Storage becomes housing: if the storage zone is converted into homes, the storage has to be rebuilt elsewhere, often in a new extension at the base.
• Livelier streets: a blank wall of storage doors feels dead. Homes with windows and front doors at street level put more eyes on the street.
• Accessibility: ground-floor homes can be reached without a lift.

Application

Plinth extension is mainly found in large renovation and retrofit projects by Dutch housing associations, often combined with topping up and a redesign of the entrance and outdoor space. It can mean building outwards or simply giving the existing ground floor a new use.

Tips and points of attention

• Permission: a change of use from storage to housing and an extension usually need planning approval. Check local planning rules first.
• Building physics: storage areas are usually unheated. Living space needs floor and wall insulation, airtightness and ventilation, and sometimes more ceiling height.
• Privacy: design a buffer zone (front garden, raised floor or low wall) between pavement and living room.
• Fire safety: check the separation between new homes, storage and escape routes.
• Services: mains connections and meter rooms often sit in the ground floor and must stay accessible.

Related terms

• Topping up a building
• Urban infill
• Repurposing
• Facade plinth
• Gallery
• Renovation

Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.