Étanchéité sur supports humides : à quoi faut-il faire particulièrement attention ?

Pourquoi l’humidité est critique

Moisture beneath a waterproof layer can turn into vapour as temperatures rise. If that vapour cannot escape, pressure may build beneath the membrane. The result can range from local blistering to complete adhesion failure.

This is why ‘suitable for damp substrates’ never means ‘suitable everywhere without assessment’. Hidden moisture, leaks from below and structural moisture sources must first be understood.

ONE® et conditions humides

Winkler positions ONE® specifically for demanding application conditions. According to the product information, the system can be applied to damp or wet surfaces and at temperatures from 0°C. The membrane is also vapour-permeable.

This can make renovation planning more flexible where perfectly dry conditions are difficult to guarantee. The substrate must still be clean, stable and free from substances that could impair adhesion.

2.0 et humidité résiduelle

For 2.0, Winkler states that application is possible on substrates with up to 8% residual moisture. At the same time, the manufacturer explicitly warns that hidden moisture must be assessed to prevent vapour-pressure build-up.

That distinction is essential: moisture measured at the surface does not necessarily describe conditions deeper in the roof or floor build-up.

Points de contrôle pratiques

• Determine the source of moisture: construction moisture, leakage, condensation or rising damp.
• Remove loose and contaminated material completely.
• Check the strength and cohesion of the substrate.
• Measure moisture where possible and use a test area.
• Use the reinforcement, primers and accessories specified by the manufacturer.
• Take processing temperature and weather forecast into account during application and curing.

Sources

• Winkler ONE®
• Winkler 2.0