▽ +09.00Problem · Concrete & walls
Cracks in the concrete
Cracks in walls, slabs or columns — some hairline, some widening or letting water through.
What you see
- Hairline map cracking on the surface
- Straight cracks across slabs or walls at regular spacing
- Cracks along the reinforcement with rust stains
- Diagonal cracks near openings or supports
- Cracks that leak water
Possible causes
Shrinkage
Early drying, poor curing and hot weather cause shrinkage cracks.
Thermal movement
Restrained expansion and contraction build stresses that crack the concrete.
Reinforcement corrosion
Rust expands and splits the concrete cover.
Settlement or overload
Structural causes that need an engineer’s assessment.
How it is diagnosed
The diagnosis confirms the cause before any repair is chosen.
Map and measure
Width, length, pattern and location of each crack.
Monitor movement
Tell-tales or gauges show whether a crack is still active.
Check for moisture and rust
Leaks and rust stains change the treatment.
Engineer’s assessment
For structural patterns: diagonal, wide or growing cracks.
- Packer
- Crack
- Injected resin
- Surface seal
Possible solutions
The fix follows the diagnosis; these are the common options and their systems.
Injection
Epoxy for dormant cracks that need bond; polyurethane for wet or leaking ones.
Systems
Concrete repair
Where corrosion has split the cover.
Systems
Protective coatings
Elastomeric anti-carbonation coats bridge fine cracks.
Systems
Crystalline treatment
For fine cracks in water-retaining structures.
Systems
What not to do
- Filling with plaster or paint only
- Injecting before the cause is known
- Rigid fillers in moving cracks
General educational content; final values and requirements follow the manufacturer’s TDS and the approved project specification.
Common questions
Are hairline cracks dangerous?
Most are shrinkage cracks with no structural concern, but they can leak in water-retaining structures, and any crack that grows needs an assessment.
What causes concrete to crack?
Plastic shrinkage during placing, drying shrinkage, thermal movement, settlement, overloading and rusting reinforcement. The pattern and location of a crack point to its cause, which decides the treatment.
Technical inspection
Need a diagnosis for your case?
Send photos, a description and the location; our engineers identify the cause and the fix after an inspection.