Maintaining Concrete Driveways and Sidewalks

Concrete driveways and sidewalks are a staple in front yards and neighbourhoods across the country. They provide a sturdy, smooth surface for walking, driving, and parking vehicles. Properly maintained concrete increases curb appeal, makes homes more welcoming, and prevents safety issues like tripping hazards.
However, concrete is still susceptible to damage over time from weather, physical impacts, ground movement, and improper installation. Without preventative maintenance and repairs, concrete surfaces can become cracked, stained, uneven, and hazardous. The average lifespan of a concrete driveway or sidewalk is about 20-30 years. With diligent care, that lifespan can be extended significantly.
Causes of Damage
Concrete driveways and sidewalks are durable, but over time, they can develop cracks, scaling, stains, and other damage. The following are a few of the most typical reasons why concrete ages:
- Settlement: As the ground underneath shifts and settles over time, it can cause the concrete to crack and sink unevenly. This often happens if the base layer under the concrete is not compacted thoroughly during installation.
- Tree roots: Nearby trees can cause damage as their roots grow under and around the concrete. The growth pressure of the roots will crack and uplift sections of the concrete. Trees that are close to a driveway or sidewalk should be monitored and root barriers installed if needed.
- Improper joint spacing: Concrete expands and contracts with temperature changes. Control joints are cut into concrete to guide this movement into controlled cracks instead of random ones. If control joints are spaced too far apart (over 10-15 feet), temperature changes will likely cause cracks between the joints.
Concrete Cracks
Cracks are one of the most common issues with concrete driveways and sidewalks. There are a few different types of cracks that can occur:
Hairline Cracks
Hairline cracks are very thin cracks that tend to be superficial and only affect the surface layer of the concrete. Typically, their width is smaller than 1/8 inch. Hairline cracks are typically caused by:
- Minor settlement or movement of the ground underneath
- Shrinkage of the concrete as it cures
- Minor thermal expansion and contraction
Hairline cracks are generally not structurally significant. However, water can seep in and cause further damage when left unrepaired. Filling and sealing hairline cracks is usually sufficient.
Structural Cracks
Structural cracks are wider cracks, typically over 1/4 inch wide. They often run deeper through the concrete slab. Structural cracks are caused by:
- Improper installation of reinforcement or joints
- Significant ground movement or settlement
- Freezing and thawing cycles
- Tree roots underneath the slab
Structural cracks indicate a stability issue that will continue to worsen over time if not addressed. They require repairs like injecting epoxy, routing and sealing, or slab jacking. The underlying cause also needs to be fixed.
Random Cracks
Random cracks appear without a set pattern and are caused by improper concrete curing or finishing. They allow moisture penetration, like hairline cracks. Sealing and filling random cracks prevents further deterioration.
Proper crack repair starts with cleaning out loose debris and dirt with a wire brush. The crack is then sealed with a concrete filler or sealant. For wider cracks, a backer rod may be inserted first to control the depth and prevent overfilling. The key is to keep water out and stop additional damage.
Concrete Stains and Discoloration
Concrete driveways and sidewalks are susceptible to a variety of stains and discolorations that can detract from their appearance over time. Common causes include:
- Oil stains: Oil that drips from cars can leave unsightly stains on concrete. These stains occur because oil penetrates the concrete. To remove oil stains, try using an industrial degreaser or emulsifier specifically designed to break down oil. Scrub it into the stain and let it soak for 10-15 minutes before rinsing thoroughly. For tougher stains, you may need to apply a poultice (an absorbent material mixed with a solvent) to draw out the oil.
- Rust stains: Rust stains occur when metal items sitting on the concrete corrode and leach iron oxide into the surface. Rust stains can be stubborn, but they can often be removed with an acidic cleaner like muriatic acid. Wet the stain, apply the cleaner, scrub with a brush, and rinse thoroughly. Be sure to follow safety precautions when using acidic cleaners.
- Efflorescence: This whitish, powdery deposit is caused when water evaporates from the concrete, depositing salts and minerals on the surface. While harmless, it can be unsightly. Efflorescence can be removed by scrubbing with water, a wire brush, or an efflorescence cleaner. But it will likely reappear until the internal moisture problem is addressed.
Concrete Resurfacing
Resurfacing a concrete driveway or sidewalk should be considered when the surface is badly damaged or deteriorated beyond repair with basic maintenance. There are a few different methods for resurfacing concrete:
Overlay
Applying a new layer of concrete over the existing surface is the most common resurfacing technique. This involves pouring fresh concrete over the old surface to create a new top layer. Overlaying is best for concrete with extensive cracking, crumbling, or holes that cannot be patched. It provides a smooth new surface. Overlaying costs $3-7 per square foot.
Topping
Topping entails spreading a layer of new concrete mix on top of the old concrete surface. The new concrete is troweled to create a finish. Topping costs slightly less than overlaying at $2-5 per square foot but does not last as long. It is best for minor resurfacing of worn or slightly damaged concrete.
Micro-Topping
Micro-topping involves troweling a thin cement-based mix on the surface to create a new finish. This method is the least expensive, at $1-3 per square foot. It does not add significant structure or thickness. Micro-topping works to update the appearance of dated, worn concrete.
The cost of resurfacing depends on the size of the area, access, site conditions, and preparation work needed. In general, resurfacing costs less than a full replacement. It can extend the life of concrete for 5-15 years. Thorough cleaning and repair of the underlying slab is key to successful resurfacing.
Patching Concrete
Patching concrete driveways and sidewalks involves repairing small, damaged areas by filling them in. It is a cost-effective solution when only minor repairs are needed.
When to Patch
- Small cracks or holes less than 2 inches wide
- Spalling or chipped areas less than 4 inches across
- Localized damage from impacts, freezing, salt use, etc.
- Minor faults that have not compromised overall integrity
Patching is ideal for minor imperfections. It restores appearance and prevents further deterioration in isolated spots.
Patching Methods
There are two main approaches:
Dry-Pack Method
- Chisel out the damaged section to a depth of 1 inch.
- Brush away all loose material.
- Mix dry-pack mortar (1 part Portland cement, 2 parts sand).
- Pack mortar into the hole and compact it in 1/2 inch layers with a trowel.
- Allow at least 48 hours for curing.
Concrete Resurfacer Method
- Chisel out the damaged section to a depth of 1/2 inch
- Sweep and clean the area thoroughly.
- Mix concrete resurfacer with water per manufacturer’s instructions.
- Fill and pack the resurfacer into the hole.
- Smooth it off flush with the surrounding surface.
- Allow at least 24 hours for curing.
The dry-pack method uses basic materials, while resurfacer products are proprietary mixes. Both work well for patching small faults.
Patching Materials
- Dry-pack mortar: Portland cement, sand, and water
- Concrete resurfacer mixes
- Bonding agents and acrylic adhesives
- Trowels, chisels, and brooms for surface prep
Use materials designed for concrete repair. Ensure patches bond effectively by cleaning surfaces first. Follow all product instructions carefully.
Preventative Maintenance of Concrete Surfaces
Regular maintenance and care are key to extending the life of concrete surfaces like driveways and sidewalks. The following advice relates to preventative maintenance:
Cleaning
- Sweep or blow leaves, dirt, and debris off the concrete regularly using a broom or leaf blower. This prevents buildup that can lead to staining.
- Wash down the concrete with a hose every so often. Avoid using a pressure washer, which can damage the surface.
- Use a concrete degreaser or cleaner to remove oil and grease stains. Scrub with a stiff bristle brush.
- To remove mould and mildew, use a bleach solution or an oxygen bleach cleaner. Rinse thoroughly.
Sealing
- Apply a concrete sealer every 1-3 years to protect against water damage, stains, salt, and freeze/thaw cycles.
- Choose a penetrating acrylic sealer for driveways and a water-based sealer for sidewalks.
- Thoroughly clean and dry the concrete before sealing. Apply it with a paint roller.
- Reapply as needed when the concrete looks faded or worn.
Inspection
- Routinely check for cracks, spalling, and other damage.
- Inspect the drainage and grade around the concrete to ensure water flows away properly.
- Look for low spots or settling that can lead to standing water.
- Fix small problems right away to stop further damage.
- Have the concrete evaluated by a professional every 3-5 years.
Regular cleaning, sealing, and inspections will extend the life of concrete and minimize the need for costly repairs down the road. Addressing problems early is key.
Final Analysis
Concrete driveways and sidewalks contribute to curb appeal and provide durability, but they can deteriorate over time due to weather, physical impacts, and improper installation. Common issues include cracks, stains, and uneven surfaces, which can be mitigated through regular maintenance like cleaning, sealing, and timely repairs.
Addressing hairline, structural, and random cracks promptly prevents further damage, while resurfacing techniques can restore heavily damaged areas. Preventative maintenance, including regular inspections and sealing, extends the lifespan of concrete surfaces.
For Edmonton homeowners needing expert concrete care, The Concrete Doctors offer professional services to keep driveways and sidewalks safe, attractive, and long-lasting. Reach out to them for a consultation and ensure your concrete stays in top condition.