Paving Over Concrete Patios: A Step-By-Step Guide

Laying pavers over an existing concrete patio is a great way to enhance your outdoor space without the hassle and expense of demolishing the old concrete. This guide will teach you how to install pavers over concrete, covering everything from preparing the concrete slab to laying the pavers and finishing the surface.

First, it's important to calculate the number of pavers needed and ensure there is sufficient space for the thickness of the pavers on top of the existing slab. Then, prepare the concrete slab by cleaning it and checking for cracks or unevenness. Fill any cracks wider than 1/8 inch with polymer-based filler.

Next, install a paver border using a polyurethane-based construction adhesive. This will require careful planning to ensure the pavers fit inside the border. After the border is complete, lay landscaping fabric over the entire slab to contain the levelling sand. Spread a thin layer of sand over the fabric, using a deck broom to get an even coating.

Now, it's time to lay the paving stones. Start in one corner and work your way towards the opposite corner, using a rubber mallet to make adjustments as needed. If partial pavers are desired at the edges, use a circular saw or angle grinder to cut the pavers to the correct size.

Finally, lock in the pavers with polymeric sand and wet the patio with a hose to activate the silica, which binds the sand together. You may also want to seal your pavers to protect them from dirt, moisture, and stains.

Prepare the concrete slab

First, prepare your existing concrete to ensure it's level and adhesive can be applied to it.

Use a level to check that the entire surface is relatively flat. Your slab should slope away from your home's foundation in all directions to direct runoff towards your yard, not your house. The ideal slope is one inch for every eight feet.

Next, look for cracks or unevenness on the surface. You might need to treat the cracks or address the underlying issue, depending on the size of the gap. Hairline cracks that haven't widened or become uneven shouldn't be an issue. Fill in cracks that are over 1/8-inch wide with polymer-based filler. If the crack is uneven across the gap, consider calling in a professional to complete concrete leveling and address the root of the problem.

Finally, clean the concrete to ensure the adhesive sticks.

Install a paver border

Before installing a paver border, ensure your existing concrete patio is in good shape, with no large cracks, a smooth surface, and no signs of scaling or spalling. Check that your patio has a slight slope away from your home to ensure proper water drainage.

Clean your concrete patio from all dirt and debris. If necessary, use a grinder to flatten any bumps or ridges on the surface.

For the border course, start laying pavers along your home, butting them against the building. Use a quality professional masonry adhesive to bond the pavers to the concrete generously. Continue laying and bonding the pavers along the perimeter of your patio.

Let the adhesive dry completely before moving on to the next step.

Note: The pavers used for the border must be at least 3/4 inch thicker than the field pavers that will cover the interior space. This thickness difference allows for a bed of sand under the interior pavers.

Lay landscaping fabric

Laying landscaping fabric is an important step in installing pavers over a concrete patio. Here is a detailed, step-by-step guide to help you through the process:

Prepare the Landscaping Fabric

Before laying the fabric, ensure that you have a clean and level surface to work with. Cut the landscaping fabric to size, allowing for a slight overlap at the corners. Make sure there are no gaps between the fabric strips, and that the edges run about halfway up the paver borders and about an inch up your foundation where the patio meets your home. Carefully cut around any columns or obstacles, ensuring full coverage.

Install the Landscaping Fabric

Once the fabric is prepared, it's time to lay it down. Start by positioning the fabric strips over the entire slab, making sure there is no movement or gaps. Use a utility knife to trim any excess fabric and ensure a precise fit. Overlap the fabric by a few inches at the corners to prevent any shifting.

Secure the Landscaping Fabric

After laying the fabric, use a heavy object or weights to temporarily secure the fabric in place. You can also staple or nail down the fabric along the edges to hold it in place. Make sure the fabric is pulled tight and smooth, with no wrinkles or bunching.

Prepare for Sand Layer

With the landscaping fabric securely in place, you are now ready to add the sand layer. The fabric will act as a barrier between the concrete slab and the sand, helping to contain the sand and prevent it from washing away.

Add Sand and Pavers

Follow the manufacturer's instructions for the type of sand you are using. Spread the sand evenly over the landscaping fabric, using a broom or a screed board for a smooth, level surface. Once the sand layer is complete, you can begin laying your pavers, following the instructions provided with your chosen paver product.

The landscaping fabric will help create a stable base for your pavers and prevent weeds from growing through. It is an essential step in ensuring the long-term durability and aesthetics of your paver project.

Put down a layer of sand

Once you've installed the border pavers, it's time to lay down a layer of sand. This will help to even out any minor imperfections in the concrete and keep the pavers from rocking. The sand also helps to reduce moisture transfer from the concrete to the pavers.

For this step, you'll need to use a fine sand, such as Basalite #1 Fine Sand or leveling paver sand. Spread a thin layer of sand over the filter fabric, making sure to get an even coating. A very thin layer of around 1/4 inch or less is usually enough, but you can use up to a 1-inch thick layer of sand if needed. Use a deck broom to move the sand over the landscape fabric, working from the inside out so you don't trap yourself in a corner.

Now you're ready to lay your paving stones!

Lay the pavers

Now that you've prepared the concrete base, it's time to lay the pavers and create your new patio. This process will require careful planning and attention to detail, but with the right tools and techniques, you'll be able to achieve a beautiful and durable result.

Step 1: Install a Paver Border

Begin by installing a paver border along the perimeter of your concrete slab. This will require careful measurement and planning to ensure your pavers fit perfectly within the designated area. Once you're satisfied with the layout, use a strong construction adhesive, such as polyurethane-based glue, to secure the border pavers in place. Check that each paver is level and make any necessary adjustments with a rubber mallet. Allow the adhesive to cure completely before proceeding to the next step.

Step 2: Lay Landscaping Fabric

The next step is to lay landscaping fabric or geo filter fabric over the entire concrete slab. This fabric will act as a barrier to prevent the levelling sand from seeping through the cracks in the concrete. Cut the fabric to size, ensuring that it covers the entire area, including the spaces between the border pavers and up the sides of your foundation. Overlap the fabric slightly at the corners to ensure no gaps are left exposed.

Step 3: Spread a Thin Layer of Sand

Now, you'll need to spread a thin layer of sand over the landscaping fabric. The sand will help to protect your pavers from moisture and create a smooth base for them to rest on. Use a deck broom to distribute the sand evenly, working from the inside out to avoid trapping yourself in a corner. A screed board can also be used to achieve a perfectly level surface, but it's not necessary for this step.

Step 4: Lay the Patio Pavers

It's finally time to lay your patio pavers! Starting from one corner, work your way towards the opposite corner, placing each paver carefully on the sand bed. It's important to use the "Click and Drop" method, avoiding any shifting or sliding of the pavers, as this can create unevenness in the sand below. Interlocking pavers are a great option, as they make the process faster and help to ensure a secure fit. Use a rubber mallet to make any necessary adjustments and maintain a level surface.

For areas where you need partial pavers, such as along the edges, use a circular saw or an angle grinder with a masonry blade to cut the pavers to the correct size. Always wear safety gear, including a respirator and goggles, when cutting pavers.

Step 5: Sweep in Polymeric Sand

Once all your pavers are in place, it's time to lock them in with polymeric sand. Spread the sand evenly over the surface of your new patio, using a shop broom to sweep it into the gaps between the pavers. Continue spreading and sweeping the sand until all the joints are completely filled. Then, use a leaf blower or angle broom to remove any excess sand from the paver surfaces. Finally, lightly mist the polymeric sand with water to activate the binding agents and help set the pavers in place.

Step 6: Consider Sealing Your Pavers (Optional)

While this step is optional, sealing your pavers can provide additional protection against dirt, moisture, and stains. To seal your pavers, simply dilute a paver sealer according to the manufacturer's instructions and apply it to the surface using a garden sprayer. It's recommended to wait two to three months after installing the pavers to allow for any trapped moisture to escape before sealing. Consult a professional if you're unsure whether your pavers would benefit from sealing.

Frequently asked questions