WLS Knowledge Base

Waterproofing damp substrates: what needs extra attention?

Moisture in a substrate is a common cause of adhesion problems and blistering. Some modern systems can tolerate moisture, but diagnosis remains essential.

Waterproofing damp substrates: what needs extra attention?

Why moisture is critical

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® and damp conditions

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 and residual moisture

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.

Practical checkpoints

Note: waterproofing is a system solution. Substrate, primer, reinforcement, detailing, coverage and weather conditions must always be assessed using the current technical documentation and actual project conditions.

Sources

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Natasha Customer Service
Natasha
Customer Service