Concrete patio – cracking
Determine the cause of the cracking as this affects the type of repair
Causes
Thermal expansion/contraction and a lack of movement control joints
Frost (on fresh concrete or where water is expanding within cracks during frosts)
Listed under: Exterior, concrete and cement, earthquakes, patios
Cause
Shrinkage cracking
Repair
- Drying shrinkage - too much water was used when the concrete was mixed
- Plastic shrinkage - crazed cracking that occurs if the surface is allowed to dry out before the concrete has gained sufficient strength
- If the cracking is not severe (if it is hairline or crazed cracking) it may be left or be resurfaced using a proprietary modified polymer concrete coating.
- Slightly larger cracking may be filled with a proprietary epoxy grout or modified polymer concrete coating: waterblast to clean the concrete surface before filling cracks, then grind the surface smooth after the fill material has cured if necessary
- If the cracking appears severe, monitor the width of a crack for a month; if it increases in size, obtain specialist advice from a chartered professional engineer
Cause
Thermal expansion/contraction and a lack of movement control joints
Repair
- If the cracking is not severe (if it is hairline or crazed cracking) it may be left or be resurfaced using a proprietary modified polymer concrete coating.
- Slightly larger cracking may be filled with a proprietary epoxy grout or modified polymer concrete coating: waterblast to clean the concrete surface before filling cracks, then grind the surface smooth after the fill material has cured if necessary
- If the cracking appears severe, monitor the width of a crack for a month; if it increases in size, obtain specialist advice from a chartered professional engineer
Cause
Frost (on fresh concrete or where water is expanding within cracks during frosts)
Repair
- If the cracking is not severe (if it is hairline or crazed cracking) it may be left or be resurfaced using a proprietary modified polymer concrete coating.
- Slightly larger cracking may be filled with a proprietary epoxy grout or modified polymer concrete coating: waterblast to clean the concrete surface before filling cracks, then grind the surface smooth after the fill material has cured if necessary
- If the cracking appears severe, monitor the width of a crack for a month; if it increases in size, obtain specialist advice from a chartered professional engineer
Cause
Building or land settlement
Repair
- If the cracking is not severe (if it is hairline or crazed cracking) it may be left or be resurfaced using a proprietary modified polymer concrete coating.
- Slightly larger cracking may be filled with a proprietary epoxy grout or modified polymer concrete coating: waterblast to clean the concrete surface before filling cracks, then grind the surface smooth after the fill material has cured if necessary
- If the cracking appears severe, monitor the width of a crack for a month; if it increases in size, obtain specialist advice from a chartered professional engineer
Cause
Earthquake - the concrete was not reinforced
Repair
- If the cracking is not severe (if it is hairline or crazed cracking) it may be left or be resurfaced using a proprietary modified polymer concrete coating.
- Slightly larger cracking may be filled with a proprietary epoxy grout or modified polymer concrete coating: waterblast to clean the concrete surface before filling cracks, then grind the surface smooth after the fill material has cured if necessary
- If the cracking appears severe, monitor the width of a crack for a month; if it increases in size, obtain specialist advice from a chartered professional engineer