Polymeric sands have really come along way since their inception in 1999 by Techni Seal. Polymeric sand is a sand formula that is swept into the joints of pavers and natural stone to lock in the product, prevent weed growth and insects, and to provide the final touches of any hardscaping job. The sand remains hard when dry and flexible when wet to allow for it to remain intact if the surface moves whether through frost cycles or traffic. It is what makes it a superior product for the filling of joints.
Over many years, the formula has improved as competition in the space grew and now today we have some pretty incredible polymeric sands on the market. Still the market is not without problems, most of which come from the installation.
The installation of polymeric sand may not get the attention it deserves because it is thought of as being a simple process that can be handed off to anyone. Unfortunately, that is not the case. There is still a lot of involvement in the process and if you miss a step or gloss over the process, you will have a failure on your hands which will cost you time and money.
It is extremely important to read the manufacturer’s instructions before you start the installation. Every manufacturer has a different formula and a different set of instructions. Even between different products in their lineup. That is why it is so important to familiarize yourself with the product that you are used to and to follow the instructions carefully.
There are universal steps to the process of installing polymeric sand, failure signs, and ways in which you can ensure that your polymeric sand installation will run smoothly.
How to Install Polymeric Sand
Installing polymeric sand involves more than just sweeping and watering. It requires some more steps to ensure that you are not going to have a failure to fix well after the installation. In this installation process, we will highlight the steps that are universal to any polymeric sand installation, as well as the steps that you should refer to the manufacturer’s installation instructions as they may differ slights (for example, watering time).
There are a few things that should be considered from an installation perspective. The base material should be free draining. That means that your bedding layer (the 1″ layer that acts as a leveler to lay your paving stones on top of) should be able to drain water. That means it should either be a concrete sand or a 1/4″ chip stone. What should not be installed is stone dust or chip dust. That is because this will harden and not allow water to drain through, keeping the water below the pavers and saturating the joints, not allowing the polymeric sand to properly dry and never set.
Your surface should be free of dust and debris prior to installation, so you can take your leaf blower or broom and clear off the surface prior to your installation. The surface should also not be wet and there should be no rain forecast for 24 hours (this time frame varies from manufacturer to manufacturer and sometimes product to product, so make sure you read the manufacturer’s instruction).
If the surface is wet / covered in snow as it would be late in the season and you may want to wrap up the job, you can take a torch and clear off / dry the stones (especially the joints) to prepare them for the installation of the polymeric sand. Most polymeric sands have a temperature range that they can be installed within until they are set (check the manufacturer’s installation instruction for this temperature which is usually 0 degrees Celsius or 32 degrees Fahrenheit). Remember that if the sand requires 24 hours to set, temperatures should not drop below this temperature overnight as well.
Your project should also have the edge restraint installed. We will be compacting the sand into the joints of the installed product, so we want to make sure that there is not room for lateral movement. Having the edge restraint installed will make sure that this will not happen during the polymeric sand installation process.
Your polymeric sand should have a minimum of 1″ in depth in the joint to be able to create a strong bond. It should also be installed 1/8″ below the top of the product or the bottom of the chamfer, whichever is the lower of the two. Failure to do this will result in the erosion of the polymeric sand and weakening its bond.
When it comes to calculating how much polymeric sand you will need, you can consult with the manufacturer of the product that you are installing. Most paver manufacturers will have this information available based on the size of the paver (less joints) and the thickness of the joints themselves. A product with lots of tighter joints may yield as much as 70-90 square feet per 50 pound bag, but a product with larger joints may yield as little as 50 square feet per 50 pound bag. Other products such as cobble stones or natural stone will yield significantly less, such as Techo-Bloc’s Antika could be as little as 30 square feet per 50 pound bag. This is important to consider especially when quoting a project.
With these factors considered, we can continue on to the installation of the sand itself, as well as the equipment that would be required to install the sand.
Making sure that your polymeric sand installation is successful requires that you have the right tools for the job. This means that you should have:
- Polymeric Sand
- Push Broom
- Leaf Blower
- Water Hose with Shower Setting
- Plate Compactor with Pad to Protect Pavers
- Dust Mask
- Torch (not required)
Using Polymeric Sand
- Spreading and Sweeping
- Sweeping and Blowing
Even something as simple as opening a bag of polymeric sand and spreading it to be swept in requires some thought. Most manufacturers recommend not to sweep the sand more than 10 feet in any direction to avoid separating the delicate formula. That means when you open a bag and pour it, you should not do so in one big pile. Try to pour it out over an area and sweep it in.
Once you have swept the sand into all of the joints, you can run a plate compactor over the surface of the stones. Unless your stone is a tumbled product (even still we would recommend this), you should have a protective barrier between your plate compactor and the pavers. This can be a pad that attaches itself to your plate compactor, a piece of carpet that you can tie to your plate compactor, or anything that you can lay down on the surface like plywood that will protect the surface of your pavers. Failing to do this will result in the scuffing of your pavers that cannot be fixed.
If your product has a larger footprint or is a natural stone, you may require a roller compactor to be able to compact the sand into the joints. These pieces of equipment will not crack your stone as you vibrate the sand into the joints, even if you are compacting 1″ natural stone slabs.
The reason why we do this step is to ensure that the sand has made its way to the bottom of the joint. The large grains of the sand will lodge themselves part of the way down the joint and will trap the smaller particles near the top making it look like the joint is filled. Using the plate compactor, you are able to make sure that the vibration causes all of the grains to make their way to the bottom of the joint. If you can make at least one pass, overlapping your passes by at least 1/3 of the width of the plate compactor, you will provide enough consolidation of the polymeric sand.
Doing this also levels out the material which reduces the high and low points in your installation, making it look smooth and complete. You will also notice that the material has locked itself together and does not move when you walk over it now.
After this compaction process, you will be left with some sand and dust residue on the surface of the stones. You will also notice that your joints need a little bit more topping up in most of the areas. You can now take the time to sweep in some more sand to the joints that need it. Now, some manufacturers claim their sand to be haze free and it does not require a blower to remove this dust before watering. What this means is that when it is watered, there is no residue that solidifies itself to the surface of the stone requiring a cleaner to remove it off. In my experience, this has not been the case and you should always remove any residue from the surface using a blower before moving on to the next step.
Watering should always start from the bottom of the slope. This ensures that you are activating the sand that you want to activate by getting to the bottom of the joint without having the water running down the slope activating only the surface of the sand if you were to start at the top of the slope. You should focus on a certain area for specific amount of time on the shower setting before continuing on to another area of the project. This is where referring to the manufacturer’s instruction is important. You should be looking for what setting to have your hose on, how long you should be watering the sand for, and how much square feet at a time you should be activating.
Any excess sand on the surface of the stones can now be blown off with your leaf blower to make sure that they do not adhere themselves to the surface of your stones.
Polymeric Sand Problems
Polymeric sand installations are not without their problems. Following the instructions is the first step to ensuring there is no failure. However, mistakes happen and there are problems with some installations. Let’s get into some of the problems and the solutions to those problems.
- Polymeric Sand Not Hardening
- Polymeric Sand Crust
- Polymeric Sand Haze
- Polymeric Sand on Pavers
- How to Remove Polymeric Sand
The number one problem that occurs with the installation of polymeric sand is that it does not set. What this looks like is the sand not hardening. A simple test for this is sticking a screwdriver into it. If it is able to penetrate the sand, then there is a problem. Typically this occurs because there was a rainfall shortly after the installation which caused the sand not to set, the sand was watered for too long, or there is not proper drainage in the base.
If the problem is caused by the base, then there is a bigger problem at hand. The solution for this would be to remove the polymeric sand, install a jointing sand, and use a joint stabilizer on the sand as an alternative to the polymeric sand. If you believe it was because the sand was too saturated or there was a rainfall before the sand set, then you can scrape out the sand and try reinstalling the polymeric sand.
If there is a crust forming on the surface of the sand, typically this means that the sand was filled too high or the sand was not watered enough. If the sand was filled too high in the initial installation, the sand will continuously be worn and eroded away. If the sand was not watered enough, then the surface was able to solidify but everything below it would remain fairly loose causing the top layer to crust and peel away. The solution to this problem is unfortunately removing the sand and replacing it much like what was described above and we will get into the process further below.
Polymeric sand haze is a dust haze that hardens to the surface of the pavers. This is caused by skipping the blowing step in the process of installation. What is left behind is the hardened dust on the surface of the pavers that needs to be removed. The process of polymeric sand haze removal involves using a saturated chemical clean the surface of the pavers and remove the haze. Click this link if you want to learn more about the process of cleaning pavers.
Knowing how to remove polymeric sand from pavers is not difficult, just time consuming and tedious. Warm to hot water actually reactivates the polymers within the sand and allows you to scrub or wash away the sand that is stuck to the surface of the pavers. If you have a small area like a corner where sand built up and hardened, you can simply boil some water and use that to pour on top of the affected areas and wash away the sand. If you have a larger area, then you will want to have a hot water pressure washer with an oscillating head to avoid wearing down the surface of the pavers to remove the polymeric sand from the surface.
Whether you are replacing and freshening up your polymeric sand or you are fixing a problem, polymeric sand removal may be required. Removing polymeric sand from pavers is not a fun process. You can try to use a hot pressure washer to remove the sand, but you may be left with some sand remaining in the joint. Regardless, you are going to have to scrape out the sand of the joints and use a shop vac or blower to remove this scraped out sand. If you are using a pressure washer, make sure that you have an oscillating head on it.
When removing sand, you want to make sure that you have at least 1″ in depth to replace the polymeric sand so that you have a strong bond. If you are removing just a portion of the sand in your entire project, it is best to remove beyond the problem area to ensure a strong bond.
What is the Best Polymeric Sand
The best polymeric sand depends entirely on the application. There are industry leaders in polymeric sands on the market that you should look for and you will likely find a product that you are used to installing over time. It is also important to choose the polymeric sand for your application.
If you are installing polymeric sand for flagstone that typically has larger joints or any product with joints larger than 1″, you are going to want to pay more money for the polymeric sand that is installed for wider joints. Most pavers will be fine with the regular polymeric sand option, unless installed on top of concrete as an overlay. In this case, there will be a specific polymeric sand for this application.
Polymeric Sand Alternative
There is an alternative to polymeric sand on the market that can be used. Azpects makes a product called EASYJoint which is installed wet and is air cured. This allows you to install it early or late in the season when polymeric sand is a little bit more difficult to install. It also allows water to permeate through, whereas polymeric sand only lets a small percentage of water to pass through. Since this product allows such a large amount of water to pass through, it is best used in applications where an open graded base is installed that allows water to pass through.
There are other alternatives on the market to polymeric sand and the formula is always in the process of refining itself to be easier to install for every user. However, we have had the most success with polymeric sand in our installations and will be using EASYJoint when necessary and on certain applications.