Interlocking concrete pavers provide a long-term solution to any pavement and the technology used to manufacture them has become increasingly better to help preserve them for a long period of time. The pavers themselves will last decades with some wear and tear that will show on the surface of them, but it really is the base and the preparation of that base that sets the foundation of that paver project up for success for years to come.
How Long Do Concrete Pavers Last
There are two factors that apply to the question: How long will pavers last? One is the pavers themselves and the other is the foundation that those pavers lay upon. Each of these factors will have their own lifespan, one more controllable than the other. Where a paver is manufactured inside of a controlled factory setting and the other is dependent on the contractor, materials, and environmental factors around it.
How Long Will Concrete Pavers Last?
Most reputable manufacturers of interlocking concrete pavers offer a limited lifetime warranty. So your pavers should last a lifetime. However, the keyword there is limited and you should always check the fine print with that. There are some factors such as properly maintaining them, clearing snow with the right guards to not scuff them, and using the right de-icing agents on them to preserve the pavers. Additionally, it is a limited lifetime warranty and with a large percentage of people moving homes every 7 years there is a high probability that most homeowners will never use that warranty for their project.
That being said, pavers last a long time. We have re-installed pavers that were upwards of 15 years old and it was just the base that failed the system and the pavers were structurally sound. This is what makes pavers a great investment compared to alternative pavement options that would need to be torn out and replaced as a whole or would have cracked from the movement that occurred from the base failure. Reputable paver manufacturers will exceed industry standards set by ASTM and CSA to ensure their product meets and exceeds a specific PSI which is higher than that of poured concrete on site.
The main thing with pavers to consider is that even though they are structurally sound, does not mean that they have not changed in appearance especially on the surface. Chips can happen over time, but the most common thing would be that the surface of the paver has worn away and the larger aggregates within the pavers are beginning to show on the surface. With traditional pavers that are smaller or tumbled to make them look old from the time they are installed, this actually compliments the aesthetic. But modern pavers are larger format and sleek which would not lend itself well to this appearance.
There is new technology in the creation of pavers to help reduce this such as factory sealing which preserves that surface. There are also face mixes that create a fine layer on top of the structural larger aggregate mixture which as it wears down over the years will continue to show just that fine layer. These are new and it will be interesting how they hold up 15 years later. Fading would be another concern, but with factory sealed pavers there is less of a concern about that. Additionally, porcelain is being embraced more and more which is resistant to fading without needing to be sealed.
There are plenty of other paver applications that have lasted 40+ years in North America.
How Long Will a Paver Base Last?
The base is dependent on the contractor that is installing the base or the methods that is used to install the base, the materials used to install the base, and the environmental factors surrounding that project. Each of these will play an important role in how long a paver base will last.
We have all seen paver projects that have failed and the majority of failure comes from the base installation and improper installation methods. Most will look at that and say that it is the pavers that failed when in reality it is the base that failed. If there was an alternative pavement solution that was installed in place of those pavers, it would have cracked such as concrete or asphalt. The pavers themselves are not the problem with the pavement failing.
Therefore, the most important aspect of the longevity of your paver project is hiring the right contractor and understanding what is proper and improper installation techniques or relying on the contractor to understand this. There are a few major aspects of the base preparation that should be understood:
- Base Depth
- Geotextiles and Geogrids
- Aggregates
- Compaction
Knowing how deep to dig for a paver project and the depth of the base depends on your climate and whether or not there is significant freeze-thaw cycles that will impact your pavement, as well as the traffic that it will handle. For pedestrian applications the minimum base depth is 4 inches, but if you are in a climate with freeze-thaw cycles that increases to 6 inches. The next aspect is your subsoil and what it is. Clay subsoils are weak and should be amended especially if they are saturated after excavation with a Type S Mortar and 3/4″ angular crushed clean stone and compacted into the clay. We choose to install an 8 inch base on top of clay, but the minimum is 6 inches. A sandy subsoil is better especially for drainage purposes and you can opt for a 6 inch base on top of that sandy subsoil. Your base should also extend past the final border pavers at a measurement that is equal to the depth of the base. This provides a solid platform for your pavers to lay upon and not slide off over time.
These are increasingly used in construction outside of the hardscape industry and help to separate, stabilize, filter, and drain. Non-woven geotextiles are good for separation and drainage, whereas woven geotextiles are good for separation and stabilization. They are placed on top of the subsoil and the base is prepared on top of them. They ensure that there is no mixing of subsoil to base or vice-versa and helps to bridge over any settlement over time with the subsoil. Geogrids are a grid-like fabric that is rolled lower or in the middle of the base material and help to stabilize the aggregates placed on top of them. You can use a biaxial or triaxial geogrid in your base to help stabilize your base.
A dense graded base is installed using a 3/4″ angular crushed stone down to fines (sand) and a concrete sand bedding layer. An open graded base is installed using a 3/4″ angular crushed clear stone (no fines) and a 1/4″ angular crushed chip stone (High Performance Bedding) as a bedding layer. A synthetic base is installed using an HPB bedding layer and paver base panels on top of that to act as the base. Any other material used in replace of these is not recognized or accepted as proper materials to install a paver base. These standards are set by the governing body of interlocking concrete pavement and manufacturers themselves to create a standard for the industry.
Stone dust or limestone screenings is one aggregate that is still used by some contractors to save money because it is the byproduct of creating aggregates. This should NEVER be used in a paver installation as it drains poorly, holds onto water, and causes the failure of pavers and the jointing compounds. It is not recognized by manufacturers as a proper material for base or bedding layers and will void their warranty if used.
Everything stated means nothing if the base is not properly compacted. A dense graded base requires moisture to be able to compact properly, whereas an open graded base does not require the same amount of force to be able to compact appropriately. The lift or the height to which you install your base material before compacting is determined by the size and force of the compactor that is being used. As a rule of thumb, for every 1,000 pounds of force that the compactor exerts you can install 1 inch of base material. Make sure to follow this appropriately to ensure the appropriate compaction for that project.
Still there are some areas that could settle. If it is a new construction home, the subsoil along the foundations which are typically not compacted when backfilled may experience settling regardless of how much compaction is completed after excavation by the paver contractor. There are other environmental factors that could also cause the base to fail, the most obvious one being if a sinkhole was to appear randomly. Not common, but not impossible.
What is Most Likely to Fail in a Paver Project
If you have a project that is completed following the steps described above, there remains two points in that system that are typically prone to failure if not maintained. Those are the edge restraint and the joint fill.
Edge restraints are typically installed using a plastic edge with 10 inch spikes. These heave over time and create unsightliness if used in a freeze-thaw climate. They were embraced by the industry when there were no great alternatives or when concrete was used as an edge restraint. Today more and more contractors are going back to a concrete edge restraint that has fibers and different additives to make it more flexible and strong with any movement. This helps the longevity of that edge restraint. Though you can opt to install a curb-like edging and have them mortared in place for your edge restraint system to prevent horizontal movement of those pavers. You can also use products like Trass bedding to install and adhere your pavers to. Trass is a cementitious mix that is added to 1/4″ angular crushed clean chip and screeded as a bedding layer. The pavers are then back-buttered with an adhesion mix and placed on top of the Trass becoming rock solid when cured. We especially like using this in porcelain applications as they are only 1 inch thick and we cannot install an edge restraint for them. This takes the place of the edge restraint system.
Joint fill is the most common point of failure. Polymeric sand is widely used for joint fill, but needs to be maintained or replaced every 5 years or so depending on the environmental factors surrounding that project. For example, a project that gets little sun or does not have an appropriate slope on it will saturate those joints longer and you will get organic growth on those joints. They will become weak and slowly start to erode. Besides a poorly constructed base, joints are the most common call we get from clients to replace. Sealing your pavers and joints is one way to extend the life of them, but is costly and also needs to be re-sealed every 3 years or so. It helps to clean your paver project at least once a year to keep organic growth to a minimum and if you see any growth, be sure to address it sooner rather than later.