Is mould always a leak?

No. It can be ventilation, condensation, cold surfaces or a leak. The pattern matters.

When should bathroom sealant be replaced?

When it has gaps, lifting edges, heavy staining or loss of adhesion.

Yes. Wet edges can damage boards, skirting and nearby cabinetry if left.

Bathroom repair guidance covering sealants, leaks, ventilation, flooring edges, mould prevention and practical bathroom maintenance.