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When correctly installed and maintained, all Unilock products will provide a durable and pleasing surface for years to come. However, like many things around the home, periodic maintenance is needed to maintain the beauty and integrity of your installation.
A general cleaning performed each spring using a coarse-bristle "stable" broom and Unilock's General Purpose Paver Cleaner, followed by the application of a granular weed preventative in the joints, can make all the difference. While dirt and algae stains are merely aesthetically unpleasing, some weeds, if left unaddressed, can push pavers apart from each other.
The joints between paving stones are undoubtedly the most vulnerable areas of any paving stone installation. Depending on the climate and amount of use, even the most expertly installed patio may require attention to the joints at some time in its life.
When using a garden hose to clean a paved area, you should direct water at the surface at an angle not greater than 30 degrees and across the diagonal (i.e., not parallel to the joints as the intensity of the water system may be too harsh and may dislodge the jointing sand). A power washer may be used but you must exercise caution to avoid damaging the surface of the pavers. Many pressure washers have enough power to expose the aggregate on the surface. Nozzle style, distance from the surface and pressure (psi) are all factors which can affect the outcome. We recommend that you always test the cleaning on several stones left over from the original installation.
Finally, when using a cleaning product, the product must be thoroughly rinsed from the surface and channeled to suitable drainage points. Once the area has been cleaned, it should be inspected to ensure the integrity of the sand joints. Any eroded joints should be re-sanded as necessary.

During the first few months after a new installation, the joints between the paving stones are relatively porous. The infiltration of rain or other water eventually consolidates the sand in the joints. However, with very sloped installations, the sand can potentially wash out of the joints. It is important that these joints be topped up with jointing sand to prevent the sand-bedding layer below from washing out, causing the pavers to settle. Keeping the joint sand topped up is also one of the best ways to prevent weed seeds from settling between the joints and germinating. To prevent weeds from taking root, we strongly recommend that paver joints be filled with Unilock Polymeric Jointing Sand. Preventing the sand from being washed or blown out of the joints is critical in this early period. Although regular jointing sand is acceptable for most applications, sloped areas, areas around swimming pools or any area subject to erosion should have Unilock Polymeric Jointing Sand swept into the joints at the time of installation. However, if regular jointing sand was used, you can also stabilize the joints by using Unilock Joint Sand Stabilizer Sealer.
Over time, the joints in a paving stone installation will become established and the joints will no longer erode. However, if wash-out occurs, we recommend "retrofitting" the joints with Unilock Polymeric Jointing Sand to re-stabilize the joints.
If you decide that you would like to replace the regular sand in your paver joints with Unilock Polymeric Jointing Sand, you will need to first remove the existing sand. This can be done with a garden hose fitted with a jet nozzle, or it can be carefully done using a pressure washer. Care must be taken that no bedding sand from the area beneath the pavers gets washed.

Product recommendation:

These products are a special mix of graded sand and binder specifically formulated for achieving optimum lock-up of pavers or slabs by filling the joints between them. Unlike regular sand, Polymeric Sand resists insect penetration, weed growth and erosion.
Alternate recommendation:
This product is a special acrylic sealer designed to bind the sand particles in the paving stone joints. This sealer should be used in applications where the use of Unilock Polymeric Jointing Sand would be impractical. This sealer also provides some protection against the penetration of stains, without creating a film or glossy appearance on the surface of the stone. An additional regular sealer is not required with this product.
General Cleaning
Cleaning is an essential step in preparing for the sealing of concrete pavers. Depending on the age of the installation and the intensity of use, the area should be inspected for any stones that may have been damaged. The perfect time to replace these stones is prior to cleaning. It is always a good idea to keep some of the stones left over from your installation for this purpose.
Make sure that any adjacent flowers, plants or shrubs are pulled back or covered to protect them from the over-spray of cleaning and sealing solutions. Before using any cleaning solution on an entire area, always test a small inconspicious area to be sure that the results are what you expect and that there is no reaction to other sealers or substances which may have been applied to the installation previously. If there is no negative surface or color reaction, proceed with cleaning the entire area. Always rinse the cleaning solution off thoroughly.
Some cleaning systems mix water and a cleaning product together in a spray. The force of the spray depends on the flow and pressure in the hose, the type of nozzle, and the distance and angle between the nozzle and the surface. Care must be taken not to blow or wash the sand from the joints. Sand will remain in the joints if a "fan" spray nozzle is used and the angle of the spray is kept from directly blasting (or targeting) the joints.


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