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definition strict definition

horizontal addition begins construction

Continuous work starts on a new addition at the side of an existing structure.

A horizontal addition to a built object begins construction when continuous work starts on a significant extension at the side of the existing object, abutting it while resting on new foundations. If the addition is built on top of the existing object, it should be classified as a vertical addition.

The extension must adjoin the existing object and have new foundations beside it. Construction of a detached object on neighboring land is not a horizontal addition.

The event is the start of continuous construction on the extension. Horizontal addition completed records when the same extension is physically finished and ready for use.

Related definitions

Definition
strict definition
Key
timeline.horizontal-addition-begins-construction
Last updated
Sep 10, 2026