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When installed properly, interlocking pavers provide a quality pavement option for driveways, walkways, and patios. They hold several benefits over alternative product options. Being able to install these products as a professional can create for yourself a profitable business in a growing industry. This takes the knowledge, trade tips and tricks, and experience in the field to be able to accomplish this. In this article, we highlight how to install pavers as a professional to ensure the longevity of a paver project.
Installing Pavers as a Professional
When it comes to preparing your interlock paver, patio, walkway driveway, it all starts with preparation in deciding what you’re going to do to install, what base preparation method you’re going to use, materials, and so on. First thing is a site visit and having an understanding of slope. We need to judge whether or not you are going to be able to lay pavers on grade or if you’re going to need to create a raised patio and steps for our patio and walkway. Driveways we do not have to worry about, as driveways are actually a very easy thing to figure out because you have a starting point which is the bottom of the garage floor and you have an ending point which is the sidewalk or the road so your slope is already predetermined with a driveway.
When it comes to a walkway or a patio, this is where slope becomes incredibly important. If it is a walkway at the side of the house where you need to worry about the swale, the swale may not allow you to be able to install a wide enough walkway without failing. This may include having to build a retaining wall to allow you to get a flat surface for your walkway. Same thing goes for a backyard patio, if your slope of your backyard is extremely steep, you may need to build a retaining wall to be able to level out that area to give you a usable patio. For the purpose of this article, we are going to be only talking about patios that are built on grade or walkways, driveways, being able to lay them exactly as-is with the slope of the yard. Learn more about raised patios.
Slope for Paver Patio
We need to calculate the slope of the actual patio to be able to understand where that patio is going to end with a known starting point at the foundation. Paver patio slope for drainage is a minimum of a 1/8 of an inch per foot to a maximum of a 1/4 of an inch per foot. The most basic method of measuring this slope and marking it out so you can continue to measure during the construction process would be to use string line.
We will put a post at the foundation of the house where the patio is starting and a post where our patio is going to end. We tie a string line on these posts that represents the top of paver. Start at the foundation where the string will represent the top of the paver and tie the string line to the post at the far end of your patio, put your string line level on that to make sure that it is level, and continue with any other posts that you have to mark your patio. Once our string line is level, we can then measure the distance from the house to the end of the patio.
In this example, our patio is eight feet long and we are going to opt for a 1/8 of an inch slope for every foot. That means that from the house to the end of the patio is going to be one inch lower (8 x 1/8 = 8/8 or 1). So we are going to lower that string line at the end of the patio one inch down.
That gives you your starting points at the foundation and the ending points at the back of the patio. Now you can adjust that as you see fit to be able to minimize the amount of steps that you need coming out of the house or to minimize the amount that you need to build up at the end of the patio. However, you can then put four different pegs for the four different corners of your patio with that slope at the top of string line should represent top of paver so from the top of paver down, you are actually going to be digging the height of the paver which is typically two and three eighths of an inch, the one inch bedding course or a screed layer, and then six to eight inches of base materials what we opt for our paver projects in our business.
How Deep to Dig for Pavers
Base preparation may vary depending on your location. Where I operate my business, we have multiple freeze-thaw cycles each year. To accommodate that we prepare a minimum of 6 inch base to a maximum of 8 inch base for patios and walkways. For driveways, we prepare a 12 to 14 inches of base.
For the depth of our excavation, we need to add the depth of our base, the one inch screed layer, and the height of our paver. We want our excavation to be uniform to match the slope of the top of the patio where the pavers are going to lay so that the slope is going to be consistent. This keeps water away from the foundation and ensures consistent movement of the base. We want that to be as consistent as possible in our install.
When it comes to excavation, you’re going to want to excavate past your project where the final paver will be at the measurement of the depth of your base. If your base is 6 to 8 inches, you are going to excavate 6 to 8 inches past that final paver. What this does is it gives your paver a nice solid platform to sit on that they are not going to start to slide outside of that base material with traffic load on them.
Prepare Ground for Pavers
Once our base has been excavated, we are then going to compact our subsoil. If we have a heavy clay soil, we may need to amend that with Portland cement mix or type s mortar mix mixed in with 3/4 inch clear stone and compacted into that clay material to increase the bearing load ability of it. This compaction of the subgrade material is incredibly important. It cannot be overlooked. You also don’t want to compact the subsoil too much to decrease the amount of water penetration.
If you have a heavy clay soil where you can roll it up into a ball really firmly, you will opt to use a ramming compactor to be able to compact. This really kneads the clay and gets the clay particles compacted properly. Alternatively, a heavy reversible compactor works for heavy clay materials. If you have a sandy subsoil, you can get away with a reversible compactor of medium size to compact that subsoil. What we use is a ramming compactor for clay. Projects with sandy soil, we use a medium size reversible plate compactor that has a force of 3,500 pounds. When it comes to compacting our base material, a good rule of thumb is that one inch of base material compaction requires 1,000 pounds of force. If you have a compactor that is only good for 1,000 pounds of force, you can only compact one inch of material at a time.
Base Preparation for Pavers
The next step is to use a woven or non woven geotextile fabric. When it comes to our projects, we are primarily using a woven geotextile fabric especially for soft subsoils. Woven geotextile impedes the passage of water, but it’s more so for the separation of our subsoil from our base materials, there is no contamination between the two of them. It also provides some tensile strengthening of our base to spread out that load over a greater area.
When installing the geotextile, we are going to roll it out on our project and ensure that there’s at least a twelve inch overlap from piece to piece while making sure that it is shingling away from the foundation. This makes sure that any water that gets on it is going away from the foundation and not going underneath another piece of fabric. We can then start with our base preparation.
There are a few different base preparation methods to do here. We can use a traditional base, which is an 3/4″ crushed stone down to fines with a concrete sand levelling layer. Alternatively, we can use High Performance Bedding (HPB) as that levelling layer which is 1/4″ angular crushed stone with no fines. We can use an open graded base which uses a 3/4″ angular crushed clear stone with no fines as an alternative to the 3/4″ crushed stone down to fines. In this application, HPB is mandatory as a bedding layer as the concrete sand will migrate into the void space of the 3/4″ stone. The purpose of an open graded base is that it allows water to filter through it with no resistance. We use this in every raised patio installation. You do require a drainage system in an open graded base installation to collect water and exfiltrate it out of the project whether it’s exiting through a wall or it is exiting through and then a pop up emitter somewhere in the yard.
The final base preparation method would be to use a synthetic base which actually minimizes the amount you would be excavating in your project. You would excavate just for that one inch bedding layer, three quarters of an inch for the synthetic base material, and then your paver at that height which is typically somewhere around four inches depending on the height of your paver. This can not be used for a driveway installation though there is a driveway installation synthetic base products out on the market that I have not yet used in my business.
In my business, we typically prepare a traditional base install for driveways with a 3/4″ crushed gravel down to fines base material of 12 to 14 inches with a HPB bedding screed layer. For walkways and patios, we are typically installing a synthetic base if it is on grade and an open graded base if it is a raised patio.
Depending on our compaction equipment available, we are going to do certain lifts of our material. If we are using a 3/4 inch clear stone, we can typically get away with a little bit more in our lifts, but it still does need to be compacted. If you are installing 3/4 inch crushed stone down to fines, you will want to wet that down to add to the compaction ability. Not too much water so that it makes it a muddy mess, but enough that you can firmly grasp a good handful of it and it is somewhat stable in your hand as a ball.
We complete a compaction of the perimeter and moving our way into the middle followed by a compaction going up and down or side to side completing two passes depending on the equipment and possibly more if need be. In the middle of our lifts, what we typically install is a biaxial geogrid. What this does is helps to stabilize our base material and spread out the load over a wider area. This is optional, but we find it’s cheap insurance for our business. To install this, it provides our client more value and sets us apart from our competition.
Screeding Level Pavers
We continue our base preparation until we get to that final one inch of bedding layer. We can measure from our string lines down to our prepared base throughout our project area to ensure we are the height of our paver plus a maximum of 1″ for our screed layer. The string line is used to ensure that we uniform in the slope of our base preparation. That is when we know we are ready to start screeding.
When screeding, we use a three quarter inch (outside diameter one inch) steel screed pipe that you can get at any home improvement place. We start at the foundation leveling out our pipes based on our string line. So at our foundation, our pipes are actually level but they’re following the slope moving away from the house. We can always lay out our pipes and then measure down from our string line to make sure that we are always that height of the paver below the top of the string line down to the top of the pipe. Now we are going to continue screeding out our project, following our string lines with those pipes from one end to the patio to the other. Our screed material is added between the pipes and a long level or straight edge is used to scrape that material backwards. We move these pipes around our projects keeping our slope and filling in the spaces where the pipes left voids.
How to Lay Pavers
Depending on our paver design, we typically have a border followed by a field of pavers for the entire project. So we can start with laying our border stone and then start laying our field out from that border. When we lay we are typically laying string lines to ensure that each row or however many rows are nice and straight following nice straight lines. We can also use a large square to ensure that we are square with our foundation. Typically instead of laying the stone and dragging it across the bedding layer, we will lay it, click it against the side of the stones already laid above the screed layer and then slowly put it down into the bedding material.
At this stage, any cuts can be completed. If we have a curved project, what we are going to do when laying our project is we will lay past our curve. Then draw a line for our curve by using something flexible or by laying your border on top to get that curve, drawing a line, kicking those pavers back and then starting our cuts along that line. With the cuts completed, we can then kick out the cut pieces to dispose of and lay our border in place. Now that our patio project is laid, we can then start thinking about our edge restraint.
Edge restraint is going to prevent lateral movement of our project. Depending on the base material that is used, you will opt for a matching edge restraint. When we are talking about an open graded base, we are going to use a concrete edge restraint. When installing this, we will scrape away that one inch bedding layer and then install a tapered concrete edge with a trowel up to an inch up the paver so that it is covering that one inch bedding layer plus one inch up our paver.
If we installed a synthetic base or a traditional base, we can opt for a plastic edge. We will scrape away the bedding material and install our plastic edge restraints in hammering non-galvanized 10″ spikes every foot or every six inches if it’s a curved patio design. These spikes are meant to corrode and hold on to the fines in the base material. This prevents them from heaving and exposing themselves. Now, this still does not prevent it 100% you still see these plastic edge restraint products heaving. So we are moving to a concrete edge restraint product for most of our installs in our business. When it comes to a synthetic base install, we are still using a plastic edge restraint because they come with anchor screws that screw in and really tightly snap into the synthetic base panels creating a solid connection.
Finally, we are ready for our jointing compound. For this, we are typically using a polymeric sand. For this install, every polymeric sand is different. You will want to consult with the manufacturer or read the bag very thoroughly to make sure that you are installing this correctly because this can fail if installed incorrectly. Typically this involves spreading out a bag and sweeping no more than 10 feet in any direction from that bag to ensure that those polymers remain at a good ratio to the sand and other particles. After that, you are going to make sure that you sweep off that surface and consolidate with a vibratory plate compactor while using a protective pad on your compactor or something to protect the pavers. This consolidates the polymeric sands to the bottom of the stone which is incredibly important. It cannot be skipped or it will lead to a failure of your polymeric sand. You can then go ahead and sweep in more polymeric sand it to top up and coming to an eighth of an inch of the chamfer or an eighth of an inch to the top of paver. This is also really important to take into factor because with traffic traveling overtop of these pavers the load will start to erode away at that polymeric sand if it is too high. If you need to, you can continue that consolidation and top up process and continue with the activation phase of installing the polymeric sand. This is going to differ from manufacturer to manufacturer.
Other jointing compounds include a basic sand jointing compound that you can then seal with a joint stabilizing sealer to ensure that it is going to stay in place. If you do not add that joint stabilizing sealer, the sand will wash out over time and weeds will take hold in it quite easily. Another option is a resin based jointing compound. There are a few of them on the market right now. These are installed by opening the product, pouring it out, and immediately wetting it to consolidate the product down to the bottom of the joints. It is an air cure product, so you do not want to let it cure to the top of stones and you are going to want to make sure that you have washed out any residue on the top of stones that does not cure on top of the stones and leave stains. There are a couple of resin based products that have a two part mixing process that are for vehicular and commercial projects on the market that you can check out as well.
After the completion of the jointing compound installation, you are going to top up the sides of your project with topsoil to build up anywhere you need to and that is the end of your paver patio installation.