Bostik Brushable Waterproofer - Black 5L

Uses

Brushable Waterproofer by Bostik delivers excellent water-resisting and sealing properties, formulated to form a water-repelling seal, aiding small bridge cracks that can cause small leaks in roofing spaces. This product is the perfect alternative for applications where the threat of frost or rain prevents the use of water-based waterproofers. Applied typically using a large brush, the surfaces that are suitable for application include;

• Mastic asphalt
• Roofing felt
• Corrugated iron
• Asbestos/Fibre cement
• Slates
• Lead
• Copper
• Zinc

Preparation

Ensure that the surface is free from contaminants that can hinder this product; these include dirt, organic growth, dust, oil, grease, rust and similar impurities. If you apply this to bitumen felt, ensure there is no moisture contained in the felt, any blisters existing should be split, allowed to dry, rebonded and sealed. Some surfaces may not allow all the contaminants to be removed, or they may be highly porous, if so, you should prime it first and allow it to dry before applying the brushable waterproofer. After this preparation, you should ensure the surface is structurally sound, clean and completely dry.

Application

1. Stir well before use; apply using a thick brush with a stiff, long handle. If the application area is smaller, use a smaller brush.
2. Apply two thin coats at a rate of 1.2 -1.5m² per litre, allowing each coat to dry before applying the other.
3. If the application requires a high build with extra reinforcement, apply a first coat. While it's still wet, place an open-woven glass fibre or an open-mesh polyester membrane into the first coat (ensuring a minimum of 50mm overlaps) and allow it to dry fully. Apply two more coats on top of this given between coats to fully dry. 

Limitations

• This product is only suitable for application if the surface is dry.
• Ensure that no moisture is present in the bitumen felt if that is the application area.