TRANSFORMING A CONCRETE SLAB TO A PAVER PATIO
Concrete pavers can be a great way to turn an old concrete slab into a beautiful paver patio, and expand your outdoor living space at the same time.
The image above was a smaller concrete slab outside the living room. Now it’s the center of their summer outdoor living and entertaining life!
Step 1 EXPAND THE AREA FOR YOUR PATIO PAVERS
Most commonly this is removing a grass area that is around your current concrete patio. You will incorporate this area into your new larger outdoor patio design. You will need to excavate about 1” deep from the surface of your current concrete slab for the area of your extended patio.REMOVAL GUIDE
Step 2 LEVEL AND COMPACT THE BASE
IMPORTANT: THE PATIO SURFACE SHOULD SLOPE AWAY FROM ANY STRUCTURE.
Using a hard rake and/or shovel, level the area and make sure it follows the slope of the concrete pad. The ground should be tightly compacted using a hand tamper or plate compactor. The slope should be about 1/4″ per one foot of distance. It is helpful to pull a string line so you can check your slope. To run a string line, attach a string to a fixed point on the house side about 3” above the surface of the patio, and pull it tight toward the outside edge of your new patio area. Attach the other end to a landscape stake in the ground making sure the string it tight. Use a level and ruler to create the desired slope. For example, the patio should slop 2.5″ over a 10 foot distance (Diagram below). This will ensure that the patio moves water away from the house.
The area should be as smooth as possible, making sure to get rid of high and low spots to within +/- 1/4″. This is now your compacted base. Congratulations, the hard part is over!STRING LINE SLOPE GUIDE
Step 3 ADD A WEED BARRIER FABRIC
Next install a layer of weed barrier fabric over the excavated and compacted area, make sure the weed barrier fabric overlaps the concrete pad by at least 12 inches. Overlap the edges of the fabric by 4-6″.
Step 4 SPREAD A THIN LAYER OF SAND
Spread an even layer of sand. Make sure the surface of the sand is level with the top of the concrete pad. Use the sand to get the surface as smooth as possible.
Step 5 LEVEL THE SAND USING A BOARD
Screed the sand using a straight board. Use a standard 2×4, about 6 feet long, straight and true! The board will also help you keep the slope so watch your string line.
Step 6 INSTALL BROCK PAVERBASE PANELS
Starting against a straight edge of the patio, lay the Brock panels, ensuring that the side flanges overlap. Ideally, lay them in a “brick-like” pattern (illustration below). This will ensure stability of the panels when you lay the pavers. Do not have a joint in the Brock PaverBase on the edge of the concrete slab. The Brock panels should span the border between the new area and the concrete slab.
Trim any curves or along edges using a razor knife. Place any extra scrap pieces of Brock PaverBase in your recycling bin.
Step 7 INSTALL THE PATIO PAVERS
Now the fun really begins! Lay the pavers directly on the Brock PaverBase panels. You can slide the pavers into place. If you are trying to do a straight line, and the line gets crooked, hammer the row back in place using a rubber mallet. Do not use the edges of the panels or the pattern on the panels to try to line up your pavers. Use a string line to ensure straightness.
INSTALL EDGE RESTRAINT.
Once you patio is complete and the pavers are tightly together you will want to hold the perimeter in place to keep it from moving. To do this simply lay pieces of edge restraint directly on top of the Brock panels. Then hammer 8-10” landscape spikes through the Brock PaverBase panel making sure to keep the edge restraint tight against the pavers.
Step 8 FINISH WITH REGULAR OR POLYMERIC JOINT SAND
Using a broom, spread sand over the patio and into the gaps between the pavers. Spread over small areas before moving onto the next one. Go back and forth over the gaps until no more sand will fit. Once you have swept the sand into the paver joints, a hand tamp should be used over the entire paver area in order to “vibrate” the sand further into the joints.
This tamping procedure will insure that the maximum amount of sand is holding the pavers in place. (DO NOT USE A PLATE COMPACTER TO VIBRATE THE PAVERS!) Continue to add sand until the joints are full.
There are two types of joint sand. Polymeric joint sand will essentially harden like concrete between your pavers. It has several advantages: It is stable, so the sand won’t end up on the top of your pavers; it allows you to power wash your patio without displacing the joint sand; it gives the patio a cleaner, more finished look. Alternatively you can use traditional joint sand, but you will need to re apply it each year. For the purposes of these instructions we will refer to Polymeric sand since it requires a few extra steps than plain joint sand.
Step 9 CLEAN THE SURFACE OF THE PAVERS
MAKE SURE THE SURFACE OF THE PAVERS IS CLEAN!
Once you are done spreading the polymeric sand into the gaps, use a leaf blower to blow the fine dust off the surface of your patio. (You want to make sure you sweep it off well first or you will generate a large dust cloud!) DO NOT WASH IT OFF WITH WATER!) THAT COMES LATER. If the patio is not free of polymeric sand on the surface of the pavers, you may see a film/haze on the pavers once you follow step 9.
Once the surface of the patio is completely clean, follow the instructions for wetting on the packaging of the polymeric sand. This will entail lightly spraying the joint sand with water several times which will activate the polymer that hardens the sand.
Step 10 BACKFILL AND FINISH YOUR NEW PATIO DESIGN
Since your new patio is by nature of a higher elevation than your old concrete slab you must address the now exposed edge. There are a few ways to do so.
The first is to back fill the area with topsoil that slowly tapers away from the patio. You can then plant grass seed in the top soil and have a finished yard right up to your new patio.
The second option is to install a short retaining or edger stone some distance from the edge of your patio and install mulch in the area in-between to use as a planting bed to further enhance you project.
Final image showing the expanded patio with all the components of patio pavers over a concrete slab.