A crack in a flat roof can be a direct route for water, but the visible crack is only part of the diagnosis. Before repairing it, check whether the defect is genuinely localised and whether the surrounding roof and deck remain sound.
What causes cracks in flat roofs?
Cracking can develop around joints, details, edges and areas affected by movement or ageing. The correct repair depends on the roof covering, the condition around the crack and whether movement or deterioration is continuing.
Why reinforcement matters
A reinforced liquid repair uses liquid waterproofing together with fleece reinforcement across an appropriate local defect. The reinforcement becomes part of the repair rather than simply painting a coating over the visible crack.
Before applying a repair
- Identify the likely water-entry point.
- Check the surrounding roof and deck for softness, sagging or widespread deterioration.
- Make sure the substrate is suitable and properly prepared.
- Use the correct primer where required and allow it to reach the specified condition before application.
- Do not work on a wet, icy, fragile or unsafe roof.
Can liquid repair bridge a crack?
On a compatible and correctly prepared substrate, a reinforced liquid system can span an appropriate local crack by incorporating fleece reinforcement into the repair area. Exact preparation, primer, application and curing requirements must follow the technical information supplied with the materials.
When not to treat it as a simple crack repair
Repeated movement, widespread cracking, a soft or sagging deck, structural concerns or an uncertain leak source should be assessed rather than covered over. Repairing the visible symptom without addressing the underlying cause can leave the actual problem unresolved.
SealForge reinforced local repair kit
For an appropriate localised defect, the SealForge Kit brings together polyurethane liquid repair material, separate fleece reinforcement, primer, catalyst and application tools. The kit is £129.99 plus delivery.
For more diagnosis help, visit the Flat Roof Leak Help Centre.