LeakSeal® FibreSeal
Blue Caulk
A water-based, fibre-reinforced hybrid polyurethane waterproofing sealant for exterior roofing seams, gaps and penetrations, providing durable, flexible waterproofing and strong tensile reinforcement.
LEAKSEAL® FibreSeal BLUE CAULK is a one-component, thixotropic, fibre-reinforced hybrid polyurethane waterproofing sealant formulated for filling and reinforcing gaps up to ±6 mm on roofing and exterior building substrates. The brush-applied paste forms a flexible, durable and highly waterproof sealing layer, delivering excellent tensile strength and crack-bridging capability across seams, edges, curbs, fasteners and penetrations.
Features & Benefits
- Excellent Waterproofing – Seals and protects against water ingress in exposed roof details
- Fibre-Reinforced Strength – Improves durability over gaps, seams and penetrations
- High Tensile Performance – Provides structural reinforcement at weak points
- Flexible & Temperature-Resistant – Accommodates movement and thermal cycling
- Water-Based Formulation – Low-odour, easy clean-up and environmentally considerate
- Thixotropic Paste Consistency – Ideal for sealing vertical and horizontal details
Intended Uses
LEAKSEAL® FibreSeal BLUE CAULK is designed for detail-repair, reinforcement and waterproof sealing of roofing gaps and junctions typically between 3–6 mm, including:
- Sealing seams, joints and overlaps
- Reinforcing curbs, roof edges and terminations
- Sealing around fasteners, fixings and penetrations
- Repairing detail cracks and localised waterproofing defects
The product is suitable for use on metal roofs, modified bitumen and single-ply membranes, concrete surfaces and roofing tiles, and is typically used as a reinforcing gap-sealer prior to the application of LEAKSEAL® FibreSeal BLUE CAULK coating systems and a UV-stable topcoat.
Compatible with:
- Metal roofing
- Modified bitumen and torch-on membranes
- Single-ply membranes
- Concrete substrates
- Clay and cement roof tiles
It is generally used before overcoating with a UV-stable waterproofing topcoat as part of a complete LEAKSEAL® system.
