The location, size, and condition of the hairline crack will best determing the best repair method for hairline cracks.
Cracks 1/32″ Or Less
If these cracks are not leaking, they are considered to be harmless. Typically you can repair them using the Armor L3000 concrete sealer.
Cracks 1/32″ Or More
If these cracks are leaking, you want to use a hydrophobic polyurethane kit which will require drilling.
If these cracks are not leaking, and are on the wall, you want to use a hydrophobic polyurethane kit which will require drilling.
If these cracks are not leaking, and are on the floor, you want to use of of the following:
- FS90, a rigid polyurethane, if the crack is in need of structural repair.
- JFX35, a flexible polyurethane, if the repair needs flexibility (expansion joint, coveseam, floor joint, joint).
