Black mould in UK bathrooms can be eliminated permanently with a simple £1 product, according to experts, who say the key is stopping moisture at the structural level rather than relying on surface cleaning or bleach.
Why Mould Returns Despite Cleaning
Guy Chapman, silicone seal specialist at United Silicones, explains that the root cause of recurring black mould is microscopic water penetration behind the sealant. 'Standard bathroom sealant looks solid, but over time it shrinks, stiffens and pulls away from the bath edge by fractions of a millimetre,' he says. 'Moisture gets trapped behind it, creating the perfect dark, damp environment for mould spores to grow. Once that happens, surface cleaning is pointless – the mould just keeps coming back.'
This means that by the time black stains become visible, mould is frequently already thriving behind ageing sealant. Consequently, simply wiping away what you can see does not address the underlying problem.
The £1 Solution: Self-Adhesive Silicone Bath Strip
Instead of removing old sealant or continuously treating mould with aggressive cleaning products, Chapman recommends using a self-adhesive silicone bath strip, which can be purchased for as little as £1. 'This works because it doesn't rely on chemical resistance. Instead, it creates a physical barrier over the vulnerable joint, stopping water from reaching the damaged sealant underneath and preventing mould from taking hold,' he explains.
Silicone strips outlast traditional sealants because they do not shrink, crack or deteriorate as readily over time. Once applied, they form a waterproof seal that helps keep moisture at bay and stops mould from developing beneath the surface. Unlike conventional sealants, which cure, age, and break down, silicone strips stay flexible indefinitely, even when constantly exposed to hot water. The outcome is a lasting fix rather than an endless cleaning routine.
How to Apply the Silicone Strip
For best results, after cleaning the bath edge, allow it to dry out completely for at least 12 hours, as any lingering moisture can compromise how securely the strip adheres. Instead of stripping out the old sealant, simply apply the silicone strip directly on top of it, pressing down firmly along the joint to create a seamless, waterproof seal.
Chapman concludes: 'For less than the cost of a coffee, you're stopping mould at the structural level. It's one of the simplest preventative fixes in the home, and one of the most effective.'
