Joints and seams are natural places to investigate when a flat roof starts leaking. A local opening, split or failed junction can allow water beneath the covering, but the correct response depends on the roof type and the condition of the surrounding area.
Signs a joint or seam may be involved
- A visible split or opening along a joint.
- An edge that has lifted or separated.
- Cracking beside a change in material or direction.
- Damp that repeatedly appears after rain near the same roof detail.
- Local deterioration while the wider roof remains serviceable.
Check the surrounding roof
Do not inspect only the obvious line. Check for nearby ponding, movement, damaged detailing and signs that the deck beneath the covering may be soft. Water can track beneath the roof surface before it appears inside.
Repairing an appropriate local seam defect
Where the defect is genuinely localised, the surrounding roof and deck are sound and the substrate is compatible, a reinforced liquid repair can provide a way to span the affected local area. Correct cleaning and preparation are essential, and the specified primer should be applied where required before the reinforced liquid layer.
The SealForge Kit — £129.99 plus delivery packages polyurethane liquid repair material with separate fleece reinforcement, primer, catalyst and application tools for an appropriate local repair.
When not to cover the seam
Multiple failed joints, continuing structural movement, widespread deterioration, trapped moisture, soft decking or an uncertain source indicate that a simple local repair may not address the problem. Seek professional assessment where those conditions are present.
Not sure where the water is entering? Read How to Find a Leak in a Flat Roof or use the Flat Roof Leak Help Centre.