Water Ingress (Damp)

Water ingress is moisture that has worked its way into the sandwich panels, seams or floor of a van or motorhome body, usually through a perished seal, a cracked panel or a loose fitting rather than a single obvious leak. Left unresolved it soaks into the panel's core, which is what eventually causes delamination — the layers of the panel separating.

A habitation check tests for it with a damp meter. Industry practice (not a legal threshold) treats a reading of up to roughly 15% as normal; higher readings call for investigation, and a re-test around three months after any repair is the standard way to confirm it has been fixed rather than just dried out. Because a documented annual habitation check is commonly a condition of a manufacturer's water-ingress warranty (often 10 years), catching ingress early is as much a financial question as a structural one.