Addition and existing house: differential settlement at the junction
A new foundation and an older house may not move the same way. Plan soil, support, joint, enclosure and services at the transition.
Decision triage
VERT / GREEN · JAUNE / YELLOW · ROUGE / RED
What the professional checks
The professional checks soil, old/new foundations, load transfer, movement accommodation, junction waterproofing and service connections.
Official sources
- SCHL — rénovation de maisons anciennes et fondations d’agrandissement
- SCHL — tassement et conditions de sol
Sources checked: 2026-08-24
Related path
Continue with the right tools
These links connect this page to the next useful checks and decisions without repeating the full content.
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V16
Advanced diagnostics to cross-check
V16 connects water, soil, climate, safety, materials and seasonal use to existing projects.
V17
Specialized systems to cross-check
V17 completes gas, soil, water, fire, climate and structural interfaces.
V27
Project risks and overlooked interfaces
V27 connects payment, water, envelope, ventilation and jobsite details that often create costly surprises.