Transforming old concrete patios to stylish paver surfaces is a popular project that can revitalize your outdoor activities at home. However, if your patio is small enough, you might be wondering if you can add pavers without using mortar.
The good news is that it is possible, and the process is nearly identical to laying a paver patio over ground. However, the installation will only work under the right circumstances, and doing it the wrong way can lead to nasty consequences.
Benefits and Challenges of Laying Pavers Over Concrete Without Mortar
There are a number of reasons why you might want to install pavers over your existing concrete rather than starting from scratch. Here are just a few of them:
- It’s more cost-effective: Instead of demolishing and disposing of the old concrete, this method takes advantage of the existing surface. That saves you money both on materials and labor.
- It’s faster to do: By leaving the existing concrete in place, you can enjoy your new surface sooner.
- It provides a stable base: The existing concrete lessens the chance of shifting and settling in the future.
- It’s easily customizable: You can choose from a wide variety of paver styles and patterns to find something that suits your taste and complements the rest of your home.
You may be intrigued by those benefits, but you’ll also want to keep these drawbacks and risks in mind:
- Risk of drainage issues: Inadequate drainage can lead to water pooling that damages the paver surface. Don’t forget to add a sand layer below the pavers, and make sure that water has a path to drain properly.
- Slight patio height increase: Adding the pavers will elevate the patio up to 3″ higher, so you may need to make accommodations in other areas to account for the height change.
- Risk of settling or cracking: If the pavers aren’t installed properly, there’s a chance the new surface could settle or crack.
- Not great for driveways: A mortarless paver installation isn’t a good idea for driveways. The underlying concrete doesn’t allow the pavers to give, so they’re more likely to rock and crack under the heavy weight of a car.
Materials and Tools
Gather these materials and tools to install pavers over concrete yourself:
- Pavers of choice
- Coarse sand
- Polymeric sand
- Edging materials
- Level
- Rubber mallet
- Plate compactor
- Drill
The Installation Process
Before you start, check the existing concrete patio’s condition. The surface should be relatively level and free from major cracks or damage. If there is severe damage or deterioration, it might be better to remove the concrete and start affresh.
You should also plan for accurate drainage across the surface. The existing concrete should have a slight slope away from your house to prevent water from pooling. Drill small drainage holes through the concrete as necessary so water can seep into the ground below.
- Clean and prep: Clean the concrete surface of dirt, debris, and vegetation, and repair any minor cracks or damage to create a smooth base.
- Install edging: Edging materials around the patio’s perimeter will help contain the sand and pavers. Be sure that the edging is firm and allows for proper drainage. If it’s watertight, your patio could turn into a bowl of water when it rains.
- Make a sand base: Spread a 1/2″ to 1″ thick bed of coarse sand over the concrete surface. Use a level and screed board to check for evenness.
- Lay the pavers: Place the pavers in your desired pattern, starting from one corner of the patio. Tap each piece into place with a rubber mallet and make sure it is level with the others.
- Fill the joints: When you’re finished laying the blocks, firm them up by filling the joints with polymeric sand. Sand joints are still permeable, but if they’re set properly, they can help excess water run off the surface rather than puddle.
- Compact and finish: Use a plate compactor to set the pavers into the sand base. Add more polymeric sand if necessary to fill any remaining gaps.
- Let the surface get settled: Give the surface a few days to set before you move heavy furniture or equipment onto it.
Later on, you can extend the size of your patio by digging out the soil around it. Install a proper gravel and sand bed, then screed and tamp the sand across both the old and new areas. However, keep in mind that the non-concreted areas will be more likely to settle, and over time your patio may become uneven.
If you’re new to these types of projects, don’t be intimidated by the prospects of mortaring a permanent paver patio. Sometimes, using mortar makes for less work.
Maintaining Your New Paver Patio
To keep the new paver surface looking great, follow these maintenance tips:
- Pressure wash the surfaces periodically to remove stains and dirt.
- Refill the joints with polymeric sand to keep them firmly packed.
- Seal the pavers to extend their lifespan.
- Address any settling or shifting issues promptly.
