The sand filling the spaces between patio pavers forms a flexible interlocking system that provides structural stability to the entire hardscape surface. This jointing material prevents individual pavers from shifting or becoming loose. Over time, environmental factors like heavy rain, wind, and routine cleaning can cause this material to erode or wash out. Periodic replenishment, often using specialized polymeric sand, is necessary to restore the integrity of the joints and maintain the patio’s long-term performance.
Preparing the Paver Joints
Before applying new material, the paver joints must be thoroughly cleaned of old sand, debris, and organic growth. The objective is to excavate the joints completely, removing the existing material down to the depth of the paver base, often around 1.5 inches deep. This ensures the new jointing material can fill the full void and create a robust bond.
A pressure washer is a common removal method, but use extreme caution to avoid damaging the pavers or washing out the underlying base material. Keep the water pressure low, holding the nozzle at a safe distance and angle to gently dislodge the old joint sand. Alternatively, use a manual joint cleaning tool to scrape out the old material, which eliminates the risk of introducing excess moisture or disturbing the sub-base.
Regardless of the cleaning method, the pavers and joints must be completely dry before application. Polymeric sand contains binding agents activated by water, and any residual moisture can prematurely activate the polymer. This premature activation can lead to staining or prevent the sand from setting properly, resulting in a weak bond. A drying period of 24 to 48 hours is required, and the project should only proceed during a stretch of dry weather.
Applying and Setting the Joint Sand
Begin by spreading the new material directly over the paver surface and sweeping it into the clean, dry joints. Use a push broom with stiff bristles to aggressively work the sand into the gaps, moving diagonally across the paver lines. Repeat this sweeping action several times to ensure every joint is completely filled.
To consolidate the sand and eliminate air pockets, the area should be compacted after the initial sweep. This is accomplished by running a plate compactor over the surface, or by using a hand tamper on smaller patios. Compaction vibrates the fine sand particles deep into the joint void. After this step, the joints will often appear lower, requiring a second application of sand to top them off. The final height of the sand should be consistently set about 1/8 inch below the paver’s top edge.
The final step for polymeric sand is the controlled watering phase, which activates the polymer binders. All residual sand dust must be swept or blown off the paver surface before watering to avoid creating a permanent haze or stain. Using a hose nozzle set to a fine mist or shower, lightly saturate the entire area until water begins to pool on the surface. This controlled introduction allows the polymer to migrate downward and set the sand mass without washing out the material.
Post-Application Care
Once the polymeric sand has been activated, the area needs protection to allow the polymers to cure and create a durable bond. Most products require an initial setting time of 24 to 48 hours, during which the area must be protected from foot traffic and heavy rain. A sudden downpour during this initial phase can compromise the bond and lead to erosion or staining.
The sand continues to harden significantly, generally reaching full strength after about 30 days. Avoid high-pressure washing or applying a paver sealer until this full curing time has passed. If any residual polymeric haze appears on the paver surface after the initial set, address it promptly with a specialized cleaning solution to prevent the residue from permanently bonding to the stone.