Polymeric sand fills the joints between interlocking pavers and helps keep a patio, walkway or driveway stable and finished. When installed correctly, it reduces joint washout, discourages weeds and insects, and helps prevent individual pavers from shifting.
However, polymeric sand is not a permanent fix for every interlock problem. Its performance depends on proper installation, drainage and a well-built base beneath the pavers. Here is what homeowners should understand before installing or replacing it.
What Is Polymeric Sand?
Polymeric sand is a fine jointing sand mixed with binding agents. After it is swept into the joints between clean, dry pavers, it is activated with water. The binding agents harden and help the sand remain in place.
Unlike ordinary jointing sand, polymeric sand is less likely to wash away during heavy rain or routine cleaning. It also creates a more finished appearance by producing consistent, stable joints between the pavers.
What Are the Benefits of Polymeric Sand?
Properly installed polymeric sand can:
- Reduce weeds growing in the paver joints
- Discourage ants and other insects from disturbing the sand
- Resist erosion caused by rain and surface water
- Help stabilize individual pavers
- Improve the finished appearance of an interlock surface
- Reduce how often the joints need to be refilled
Polymeric sand does not completely prevent weeds. Seeds can still settle and grow in dirt that accumulates on top of the joints. Regular sweeping and occasional cleaning remain important.
Does Polymeric Sand Prevent Interlock From Shifting?
Polymeric sand helps stabilize the pavers, but it cannot compensate for a poorly prepared base.
The strength and durability of an interlock surface begin below the pavers. Proper excavation, compacted aggregate, grading, edge restraints and drainage are all essential. If the base settles or water collects beneath the surface, the pavers may shift regardless of the jointing sand used.
Learn more about how we build durable interlock patios, walkways and driveways.
How Is Polymeric Sand Installed?
Installation requirements vary by product, but the basic process generally includes the following steps.
1. Clean and Dry the Pavers
The pavers and joints must be completely clean and dry before installation. Existing weeds, loose sand and debris should be removed so the new sand can properly fill the joints.
2. Spread the Sand
The polymeric sand is spread across the surface and swept into the joints. The joints must be filled to the depth and level recommended by the manufacturer.
3. Compact the Surface
A plate compactor is typically used to help the sand settle deeply and evenly between the pavers. Additional sand may be added and compacted until the joints are properly filled.
4. Remove Sand From the Pavers
All remaining sand and dust must be carefully removed from the surface before water is applied. Sand left on the face of the pavers can harden and create a cloudy residue known as polymeric haze.
5. Activate the Sand With Water
The surface is watered according to the product instructions. Too little water may prevent the binding agents from activating fully, while too much water can wash material out of the joints.
The area must then remain dry and undisturbed for the recommended curing period.
Why Does Polymeric Sand Sometimes Fail?
Common causes of failure include:
- Installing the sand on damp pavers
- Leaving dust or sand on the paver surface
- Applying too much or too little water
- Using the wrong product for the joint width
- Failing to fill the joints deeply enough
- Poor drainage or standing water
- Movement caused by an unstable base
- Applying the product when rain is expected
- Using a pressure washer too aggressively
Ontario’s freeze-and-thaw cycles can also expose weaknesses in the base or drainage. If an interlock area repeatedly shifts, sinks or holds water, replacing the polymeric sand alone will not solve the underlying problem.
Can Polymeric Sand Be Replaced?
Yes. Over time, polymeric sand can crack, erode or become contaminated with dirt and organic material. Damaged sand can be removed and replaced if the pavers and base remain in good condition.
Before replacing it, the surface should be inspected for loose pavers, settlement, drainage problems and damaged edge restraints. Repairs should be completed first so the new jointing sand is not being used to hide a larger issue.
How Long Does Polymeric Sand Last?
There is no single lifespan that applies to every installation. Longevity depends on:
- The quality of the product
- Correct installation
- Joint depth and width
- Drainage conditions
- Sun and weather exposure
- Traffic on the surface
- Cleaning and maintenance practices
- Stability of the interlock base
A properly built and maintained surface should not require new polymeric sand every year. Small areas may occasionally need attention, but widespread or repeated joint failure usually deserves a closer inspection.
How Should Interlock With Polymeric Sand Be Maintained?
Sweep the surface regularly to prevent soil and debris from building up in the joints. Remove weeds when they first appear and address drainage issues promptly.
If using a pressure washer, avoid directing a concentrated stream into the joints. Excessive pressure can loosen or remove the sand. Gentle washing and an appropriate surface cleaner are safer choices.
Homeowners planning a new patio should also consider layout, drainage and long-term maintenance before choosing materials. Our guide to planning an interlock patio that lasts covers these decisions in more detail.
Is Polymeric Sand Right for Your Project?
Polymeric sand is a valuable part of a properly installed interlock surface, but it is only one component. Long-term performance depends on the complete installation—from excavation and base preparation to grading, paver placement and joint finishing.
If you are comparing surface materials, read our guide to interlock versus concrete in Ontario.
Earthworks Landscaping & Pools installs interlock patios, walkways, driveways and front entrances throughout Burlington, Oakville and surrounding communities. Contact us to discuss your project and request a detailed quote.
