Character Of The Issue – Requirements

Waterproofing a metal roof is essential to mitigate vulnerabilities that may compromise its watertight integrity over time. Although metal is inherently durable, the assembly, which includes joints, fasteners, and protective layers, is susceptible to various environmental and mechanical stressors.

Preparation of the substrate

The surface designated for coating must meet the following criteria:

• It should be dry and stable.
• It must be free of any materials that could hinder bonding, such as dust, loose particles, and grease.
• It should be devoid of rust or any corrosion that may interfere with adhesion.

Depending on the substrate’s characteristics, appropriate preparation techniques such as brushing, grinding, or sandblasting should be employed. Subsequently, the surface must be thoroughly cleaned to remove any dust.

Rust Removal and Passivation

Rust Removal: Begin by applying PC-Rustproof® RC, a single-component liquid specifically formulated to eliminate rust and provide temporary protection against further oxidation. This product can be applied using either a brush or a spray. Allow the reddish corrosion to change to a near-black color, indicating effective removal.

Surface Priming

PC-Prime® EP 2C is applied in two layers using a roller, brush, or spray technique. The second layer should be applied after the first has dried, but within 24 hours. The recommended consumption rate is 150-200 g/m² per layer.

Following the application of PC-Prime® EP 2C, PC-Sealcoat® 220 should be applied within the next 24 hours.

It is essential to seal the edges where the metal roof meets vertical elements such as parapets and stairwell terminations, as well as pipe joints, ventilation joints, metal element joints, connection joints between metal sheets or panels, screws, and joints on the substrate wider than 1 mm. This sealing should be done using the polyurethane sealants PC-Sealants® PU 25, 12 to 24 hours after the application of the epoxy primer.