Softens, stains and loses paper bond when repeatedly wet.
What changes first
Look for water staining, softened edges and paper damage. The pattern and location usually matter more than color alone.
Moisture and movement behavior
Record whether the material changes after rain, water use, heating cycles or seasonal humidity. A material can display the damage while the source is somewhere else.
Before repair
Determine whether the material is the source, a pathway or only the final surface. Correct the controlling condition before replacing finishes.
Observe→Distinguish→Control source→Verify
Living dossierPublished knowledge is connected and improved as new cases, images and outcomes are added. Updated 2026-07-20.
