Preventing Basement Leaks

Main measures

• Exterior waterproofing coating
• Drainage around foundations
• Proper grading of surrounding soil
• Sealing penetrations

Gilsonite coatings form part of a complete system.

Finding the source

Before choosing a repair, find where water enters: cracks in walls, the wall–floor joint, pipe penetrations, window wells or poor drainage outside.

Exterior solutions (best)

• Excavate, clean and dry the wall.
• Apply gilsonite-based primer and two coats of waterproofing.
• Add drainage board and a perimeter drain at footing level.
• Regrade soil so it slopes away from the building.

Interior solutions

Interior coatings and drainage channels can manage water but do not stop it entering the wall. They are useful where excavation is impossible.

Maintenance

Keep gutters and downpipes clean and discharge water at least 1.5–2 m from the foundation. Many basement leaks start with poor surface drainage.

See waterproofing grade gilsonite and foundation waterproofing.