Cracks and subsidence: building the file before the expert arrives

A crack photographed and dated is worth infinitely more than a crack described from memory three years later.

Cracks appear on the façade, widen in summer, partly close in winter. A door stops closing, a tile lifts. In clay areas this pattern often means shrink-swell of the soil: clay contracts in dry spells and swells with rain, and the building moves with it.

This kind of damage falls under a particular regime: it can be covered as a natural disaster, provided an official order has recognised that status for the area and period. For a building, the whole difficulty lies in deadlines and proof.

Telling cracks apart

• Shrinkage micro-cracks in render, superficial and structurally harmless — the most common.
• Stepped cracks following the masonry joints, signalling movement.
• Through-cracks, visible on both sides of a wall.
• Cracks that change with the seasons: the most characteristic sign of ground movement.
• Associated defects: sticking doors, uneven floors, corners pulling apart.

The board does not classify these — that is a professional’s job. But it has an irreplaceable role: observe early and document, as described in the incident log.

What to do from the first crack

The quality of the file depends almost entirely on what was recorded before the survey. Four simple habits, repeated every year:

• Photograph each crack with a scale reference and a visible date.
• Note the exact location: façade, floor, orientation, proximity of a tree or a service run.
• Measure the opening at the same point each time, marking the measuring spot discreetly.
• Record interior defects reported by occupants, flat by flat.

Photographic tracking over three seasons is worth more than a survey with no history. These readings belong in the annual walk-through.

Declaration and its deadlines

Natural disaster recognition is sought at local authority level, and compensation requires a declaration to the insurer within a short period after the order is published. That deadline is the most frequent trap: a building that misses it loses the benefit of the cover, however real the damage.

The board should therefore ask the manager to watch for orders concerning the area, and to declare without delay. The file then follows the logic in handling a claim and the building policy’s cover.

What can make it worse

Some factors amplify ground movement: a large tree too close to the building, a leak on a buried pipe, rainwater badly drained at the foot of the façade, or conversely ground made entirely impermeable.

The board can check these, and dealing with them is routine upkeep: see grounds and tree work and leak detection.

Without a dated photo, a three-year-old crack is indistinguishable from yesterday’s: that is where files are lost.

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