Choosing Interlock Paving Jointing Compound

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Jointing materials for paving stones have come a long way in recent years from installing a basic jointing sand to the several options available on the market today. Choosing the right jointing compound for your project is crucial to ensure the structural integrity of your project, as much as the installation of that material is.

The various jointing compounds on the market today have different applications that should be considered carefully when deciding when and where to use them. Though the application is the number one consideration for choosing the right jointing product for your paving stones, there are other factors that also should be considered.

In this post, we are going to discuss three different types of jointing compounds that you can use in the joints of your pavers. Each of them have their benefits and drawbacks to using them. Choosing the right jointing compound for your project depends entirely on your project, as well as what you are comfortable with installing yourself.


interlock-paving-jointing-compound

Choosing a Paver Jointing Compound

Jointing compounds fill in the joints between the paving stones. It is meant to bind and lock the stones together creating a structurally sound surface that can withstand vehicular and / or pedestrian traffic that travels over top of it. It is a crucial final step of the installation process with paving stones. The selection of jointing materials has increased over the years, as has the quality in those materials allowing users to choose the right jointing compound for the specific application.

When it comes to choosing the right paver jointing compound for your project, you need to evaluate a few different things with your project as each of the jointing compounds have different benefits to it.

  1. Vehicular / Pedestrian Traffic
  2. Not every jointing compound is applicable to every project. Some jointing compounds are not applicable to projects that are subject to vehicular traffic such as driveways. This is because they are not suitable to bond the pavers to resist the torque of the twisting and turning of vehicles on the pavement and act more as a joint filler. In this case, these projects are suitable only to pedestrian traffic areas.

  3. Base Material
  4. The base material that you use is important to choosing the type of jointing compound that you will apply. If you use limestone screenings, stone dust, chip dust, or whatever it is called where you are located as a bedding material for your pavers, it is likely that whatever jointing material you use will have issues. This is an outdated material to use as a bedding material because of its lack of drainage which will cause numerous issues with your install, the very least of which will be a void warranty from the manufacturer of the product you are installing.

    If you use a traditional base installation with a Granular A material or 3/4″ angular crushed stone down to fines as the base with a concrete sand bedding material, then you are likely going to stick with a jointing sand or polymeric sand product for your install. Though if you move towards a hybrid base or an open graded base where you use a 3/4″ clear stone as the base with a 3/16″ or 1/4″ angular chip as your bedding material, then you likely have more flexibility with which material you choose to install as the jointing compound. Due to its free-draining material used in the base, a resin-based jointing compound that allows for the free-flowing of surface water through the joints is the most suitable option for this base. Finally, in an overlay system where the pavers are set on top of a concrete pad, the installation most likely calls for the installation of a polymeric sand which resists the flow of water downward to that concrete slab.

  5. Joint Width
  6. This is an important aspect of your install that will dictate the material that you will be able to get into the joints or that will be able to bond the stones. If your joints are extremely thin, you will be forced to choose a product that has a fine enough grain and is able to get into those joints. A fine-grained polymeric sand is likely the best bet for these scenarios with numerous passes on a plate compactor to consolidate that sand in order to vibrate it through those thin joints to the base of the paver.

    A product with a large joint, such as the installation of random natural flagstone, requires a product that is applicable to this install. Most polymeric sands are able to be installed up to 1″ wide gaps with some more specialized products able to be installed up to 4″. Other resin based materials can be used for larger joints. Ultimately if your joint widths are larger than 1″ you will want to consult the product specifications for the material you want to use as a jointing compound to ensure that it is suitable to your joint widths.



  7. Comfort / Experience
  8. This definitely plays a major role in the installation. You want to make sure that you are installing a product that you are comfortable with installing based on your experience. If you are comfortable with polymeric sand (remember that the installation procedure for polymeric sand changes from one manufacturer to another) and it is applicable to your install, then this is the product you will likely want to stick with. On the other hand, if you are comfortable with learning new installation methods like preparing an open graded base, then you will likely want to experiment with new jointing compounds on the market to ensure that you are choosing the best option for your project.

  9. Appeal
  10. No two jointing compounds look the same. There can be a difference in the size of the grain which will affect the appearance of the material, as well as the color of the grain itself. This is a little bit less of a factor to consider, but for some it can really make the difference in their project.

 

Sanding Paver Joints

The steps for every jointing compound will be different. Even the steps for the same type of sand will have different directions for installation from manufacturer to manufacturer. This is because the ingredients within that compound is different and proprietary to that specific manufacturer. That means that a polymeric sand from one manufacturer will have a different installation than that of another compactors. It is incredibly important to understand that in your installation, otherwise there will be problems in the future with that install. Alternatively if you are not comfortable with familiarizing yourself with different directions for different products, find one that suits your typical installation and stick with that one.

Typically the installation of a jointing compound follows a few steps:

  1. Spreading
  2. In this process, the material is swept or moved around the surface of the project to ensure that the sand is filling the joints of the paving stones.

  3. Consolidating
  4. This is the process of moving that jointing compound to the bottom of the paving stone. In an application like polymeric sand, this means vibrating that sand to the base of that paving stones. In an application like some resin-based jointing compounds, it means flushing with water to consolidate that material to the base of the paving stones.

  5. Activating
  6. This is typically a final step where the material is then activated and cured over a period of time to ensure that it has successfully bonded to the paving stones. For polymeric sand, this involves activating the product with water. For resin-based jointing compounds, it is allowing that product to air cure over a period of time.

 

Best Sand for Paver Joints

What is the best jointing compound for paving stones? Well let’s get into a few different options, their applications, and the pros and cons between the various choices that you have on the market.

  • Jointing Sand

  • This option has been available since the beginning of time and is basically a fine grain of sand that is more angular crushed to prevent washout. It is simply swept in when dry. If it is wet, it should be spread out on a separate surface before being swept into the joints of the paving stones. It should also be consolidated with a compactor with a mat to protect the surface of the pavers underneath. Finally, it is topped up with some more jointing sand in place of the sand that had been consolidated to the bottom.

    The installation of brick paving jointing sand can be as simple as that, but the main consequence is that it is susceptible to weeds, insects, and washout over time that will need to be replaced if it were not to be already overrun by the other two. It really does not hold a place in a residential install anymore.

    However, typically block paving jointing sand now and in the past had an additive that is a joint stabilizer. This was added to the jointing sand to create a bond to prevent all of those consequences above. Nowadays, this comes in the form of a sealer that is applied afterwards to the surface of the stones and locking in the jointing sand while preventing weeds, insects, and washout.

    The unfortunate part of this step of the process is that if the pavers have just come out of production, typically the manufacturer asks that you wait a certain time period before sealing the stones. That means your project could be sitting for some time without a jointing compound installed in it. For a driveway, this can be difficult for the client to manage. For a backyard patio with trees overhead, this could mean that weed seeds have already started to form within the joints of the pavers. At the very least, you will need to come back at a later date to pressure wash and clean the stones. You would then need to come back at a later date when it is completely dry to install the dry jointing sand before sealing paver joints.

    Polymeric Sand vs Regular Sand for Pavers

    What is the argument for jointing sand vs polymeric sand? Well, we do not believe there is one anymore. Polymeric sand has come a long way since its inception in the early 2000s and is a quality product for a jointing compound these days. Save yourself the headaches when it comes to the install of such an important component of your paving project and install the jointing compound in one day. There are alternative additives that you could get into that stabilize jointing sands without having to completely seal a project, but for the most part there are better products available on the market to help with your project.

  • Polymeric Sand

  • These days polymeric sand tends to be the industry standard in most installations. No matter the application, there is a polymeric sand available on the market. Driveways, patios, walkways, overlays, swimming pool patios, all of these types of projects on a traditional or open graded base can be installed with a polymeric sand. Some manufacturers have different levels or grades of polymeric sands that should be considered for projects that get a lot of water introduced to it such as pool patios. This should be considered when deciding on a manufacturer and then the type of polymeric sand that they have in their lineup for your specific project. Specifically when considering a polymeric sand for wide joints. Most manufacturers have a grade of polymeric sand for joints up to 1″ and then a separate grade of polymeric sand to reach up to 4″. It is extremely important to follow these specifications and not exceed them, otherwise the project is most certainly not going to set as anticipated.

    Using Polymeric Sand



    A typical installation of polymeric sand requires a dry surface and joints, as well as no rain in the forecast for a day. That being said, most manufacturers now have polymeric sand products that are rain safe as fast as 15 minutes after activation. Still, it is best that there is no torrential downpour in the forecast. Because polymeric sand requires such a dry period of time, it makes it difficult during the early spring and late fall periods when projects need to be wrapped up and can leave some projects needing to be wrapped up in the next season in order to be able to install the sand. One quick fix of this would be to purchase a torch kit to hook up to your propane tank and to dry up the surface of that stone, especially the joints so that the polymeric sand can be installed. An additional note would be that the temperatures cannot fall below a certain temperature for a certain period of time during and after installation. Always check with the manufacturer for this information as it varies.



    The sand is then brushed into the joints, consolidated with a compactor and mat to protect the surface of the stone, and then topped up with additional polymeric sand. The sand is then blown off with a leaf blower to ensure there is no dust or residue on the surface and then activated with water (check with the manufacturer on how to water the sand) and given some time to cure.

    The unfortunate side to these steps is that because they vary so greatly from one manufacturer to another and also because it is a process that is often overlooked, there are noted cases of polymeric sand failures that need to be fixed. The installation of polymeric sand may look uncomplicated, but there is a lot of work that goes in to making sure that it is installed and works properly.

    Best Polymeric Sand for Pavers

    When it comes to polymeric sand, no to sands are made equal and everyone will have a specific sand that works best for them. The sand contains the grains of sand and polymers to create the bond, while some manufacturers add other ingredients like Portland cement to add some strength. The best way to find a recommended product would be to go to a local stone supplier that specializes with paving stones and see what they have in stock, what they suggest, and use that product according to the manufacturer guidelines. We have a couple of favorites that you can contact us to ask about.



  • Resin Jointing Compound

  • There are numerous resin-based jointing compounds that have hit the market in North America recently, but have been tried and tested in Europe for many years prior. These compounds are typically air cured and installed with water to consolidate and prevent it from curing prematurely. This has several benefits that are worth noting, one specifically being that it can be installed in the rain! That means that you can install this in the latter part of the fall season to wrap up a project as long as temperatures do not fall below the specified point by the manufacturer.

    That being said, we see these solutions being a patio jointing compound as they do not have the bonding ability to the paving stones to withstand vehicular traffic. Additionally, these are typically permeable solutions that allow for the flow of water through the joints. This makes it the perfect solution for environments and applications that get a lot of water. This is especially the jointing compound of for a patio that is built using an open graded base which has no fines in the base material which allows for the free flowing of water through the base and into the sub grade or to a drainage pipe. This is our solution for raised patio applications for this reason and is also the reason why we would rate this the best patio jointing compound if it is installed using open graded base.

    The installation method is generally as simple as wetting down the entire surface of a project, pouring out a bag of the material that is contained in an airtight bag, hitting it with lots of water, and brushing it around the surface to fill in the joints while continuously hitting it with water to consolidate the material and preventing it from prematurely curing. In addition to this, a lot of water needs to be used to rinse off the surface of the pavers from the resin to avoid any discoloration of the material.


    resin-jointin-compound-for-pavers

    resin-jointin-compound

    Because these jointing compounds are air cured, they cannot be installed in an area that is always wet or has a consistent source of water being introduced into it otherwise it will never fully set. Additionally, there is a minimum joint width for this to be installed and it cannot be used in driveway applications.

    As these compounds become more advanced, we see them becoming increasingly popular, especially as the installation of hybrid bases like open graded base become more prominent. Their ability to allow water to permeate through the joints and into the base material is an incredible bonus for the application.

  • Permeable Jointing Stone

  • Much like the permeable resin-based jointing compounds, this jointing solution allows water to permeate through the joints and into the base material. However, this option does so at a much faster rate and is really only a solution for permeable installations. This product is typically an ASTM#9 stone that is angular crushed and is simply swept into place in the joints with some consolidation taking place using a plate compactor once the surface has been protected.

    The addition of a stabilizing liquid can be added to these joints to keep the jointing stone from moving and coming out from the joints. However, due to its size and angular shape this is less likely to happen to this material compared to that of jointing sand. This material is most likely to be used in a commercial permeable application, though as the increase in demand for permeable pavements in residential systems increase we may see this stone being used more often.

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