Before you have any concrete work done, it's a good idea to inform and prepare yourself.
If you're an installer or a DIYer in need of some tips, this information could help your concrete jobs perform well and last for decades without serious maintenance issues. If you're a property owner, don't be afraid to ask your installer questions about the concrete they're using for your property, and their finishing techniques. A reference check could also help you make sure your installer has a good record before they do any work on your property.
Blisters are bubbles of air or water trapped just beneath the surface of concrete. They are most often caused by improper or hasty finishing techniques.
- Apply proper levels of vibration and compacting
- Allow adequate time for excess air and water to escape before finishing
- Ensure that trowel is held flat
- Use wood or magnesium floats on the first pass
Concrete cracking can occur for a number of reasons, including freeze and thaw cycles, drying shrinkage, and heavy traffic.
- Use an appropriate concrete mix for anticipated traffic
- Use concrete and additives suited to extreme temperature changes
Crazing takes place when a series of small surface cracks connect, giving the surface a spiderweb appearance. Crazing is most often caused by rapid drying due to heat or high winds, overworking the surface during finishing, or use of dry cement to absorb excess water.
- Use concrete and additives suited to hot, dry, or windy conditions
- Use proper finishing tools and techniques
- Begin curing immediately
Discolouration can happen for a number of reasons, including fading, colour differences between batches, and stains from oil and other products. Calcium chloride added to cold concrete or in improper conditions can may fail to mix properly and cause spots of discolouration as well.
- Maintain consistent pouring, finishing, and curing conditions
- Avoid pellet calcium chloride
- Apply a new seal every year
- For coloured concrete, increase the amount of pigment to account for fading
A fine layer of concrete dust sometimes appears on a concrete surface. This is usually due to premature finishing and and curing, or damp conditions.
- Do not proceed with finishing until all water has evaporated out
- Allow adequate time for curing
- Choose a concrete and additive mix suitable for high-condensation conditions
Plastic shrinkage appears as small cracks on a concrete surface. They are typically caused by rapid evaporation of water from the concrete surface due to heat, high winds, or other environmental conditions.
- Select a concrete and additives well suited to dry, hot, or windy conditions
- Minimize pouring and finishing time
- Use windbreaks to protect concrete while setting
Scaling occurs when small pieces of concrete are chipped away from the surface, leaving a rough or bumpy texture. This may be cause by salting, freeze/thaw cycles, or poor finishing techniques.
- Select concrete and additives that are suited to a cold climate
- Ensure that concrete is finished smoothly and carefully and not rushed
- Avoid salting the surface for one year
- Ensure the concrete is cured at least 30 days before freezing conditions are expected