How long does damp proofing last?

A properly installed chemical damp proof course is designed to last the lifetime of the building, because the silicone-based cream forms a permanent water-repellent barrier within the masonry. Our treatments carry long-term guarantees, typically 10–30 years depending on the treatment and property, and the guarantees are insurance-backed so they survive even if the installing company doesn't.

What keeps it working

• Keep external ground levels below the DPC line: flower beds and paving built up against a wall will bridge any DPC, however good
• Maintain gutters, downpipes, and pointing so the wall isn't being soaked from outside
• Fix plumbing leaks promptly
• Don't seal treated walls with impermeable paints or renders that stop them breathing

If damp comes back

Recurrence is usually caused by a new moisture source rather than treatment failure: a raised patio, a leaking washing machine, or blocked gutters. Diagnose before assuming the worst: a survey identifies whether it's the old problem or a new one, which also determines whether a guarantee claim applies. Keep your guarantee documents with your property papers; buyers' solicitors will ask for them when you sell.