Polymeric Joint Sand Withstands the Test of Time

Phil Graves, Techni-Seal, South Central US Regional Sales Manager

Depending on the size of the sand bag and the paver style and thickness, evenly space and break bags every 50 to 100 square feet of pavement. Put it in the joints. Note the logistical ease of carrying and dropping bagged sand, especially if the pavement is long and narrow or next to a pool. Using the push broom, sweep the sand until the joints are completely filled.

If there is a valid argument against selecting a properly installed interlocking concrete pavement, it is that the joint sand creates ongoing maintenance issues. Joint sand can be fertile ground for airborne weed seeds and an inviting home for nearby ant colonies. It also erodes with rain and wind, ending up in a number of places other than between the pavers.

As with regular sand, make a pass with the plate compactor to eliminate any potential bridging in the joints. After compaction, sweep additional sand as needed until the joints are full to the bottom of the chamfer or to a uniform depth of 1/8th of an inch below the surface of a non-chamfered paver. Filling above this level diminishes the pavement?EUR??,,????'???s ability to channel water and exposes the sand to excessive abrasion from traffic.

These issues are exacerbated with tumbled pavers and pavers with irregular edges and rounded corners, which happen to be the styles increasingly desired by homeowners and architects alike. For installation professionals, joint sand problems can also erode profits. Not only does a single callback to re-sweep sand decrease the profitability of that job, it also erodes time that?EUR??,,????'???s better spent on a new installation or sales call. Future sales can erode when potential customers observe their neighbors repeatedly sweeping sand and spraying weed killer on their pavements.

Polymeric joint sand effectively removes that singular reasonable argument against owning an interlocking concrete pavement and allows jobs to withstand the test of time. Representing, on average, less than 5 percent of the overall cost of the job, polymeric joint sand is quite simply the best solution there is when it comes to erosion control, weed inhibition, insect resistance and overall surface response to movement.

Tools Required

Installation pros recognize that the ease of installation only serves to complement the performance benefits. The list of tools required is short and consists of items almost certainly already onsite: Push broom; Vibratory plate compactor; Leaf blower; Hose with misting nozzle; Screwdriver or pocket knife.

As moisture activates the polymeric binder, ensure the pavement is dry prior to application, with no rain in the forecast for 24 hours. Sweep additional sand as needed until the joints are full to the bottom of the chamfer or to a uniform depth of 1/8th of an inch below the surface of a non-chamfered paver. Filling above this level diminishes the pavement?EUR??,,????'???s ability to channel water and exposes the sand to excessive abrasion from traffic. Additional passes with the plate compactor may be necessary, as tighter compaction results in greater stability and stronger polymeric bonds. When the joints are full, sweep the pavement clean of excess sand and blow off remaining residue with a leaf blower. Keep the leaf blower above knee height and at a shallow angle to avoid displacing sand from the joints.

Polymeric sand is a high-tech mix of graded sand and binder. Activated by a misting of water at installation, the polymeric molecules form a strong yet flexible bond with the sand. Depending on the manufacturer of the sand, that bond has proven in the field to last for more than a decade.

Moisten the entire depth of the joint with as little water as possible.

The Wetting Process

Once the pavement is clean, the wetting process can be summed up in one simple phrase: ?EUR??,,????'??Moisten the entire depth of the joint with as little water as possible.?EUR??,,????'?? The entire joint needs to be moist because the polymeric binder is mixed with the sand all the way to the bottom of the joint and needs to be activated in order to ensure the best possible performance. Too much water however, and the polymer could rise to the surface and wash away or form a crust at the top of the joint only.

Empty the sand out of a joint at several different locations on the pavement with a screwdriver or pocket knife to ensure full-depth moisture. Speed and efficiency of polymeric sand installation come with just a little practice, but proper technique is the highest priority, for once the polymer has been activated, it cannot be undone.

The joint sand should conform to ASTM-C144 requirements as well as to the requirements laid out in ICPI Tech Spec #9. Sands with particles that are too large create additional compaction time and frequent bridging events that result in voids in the joints and weak polymer bonds. Sands that are too fine are easy to sweep but lack structural integrity due to a more uniform particle size and less angularity.

Keep It Dry for 24 Hours

Once the wetting process is complete, inform the property owner that sprinkler systems must remain off for at least 24 hours. If the forecast changes to include a chance of rain, lay a tarp over the pavement to protect the joints. When selecting a polymeric sand, as with any manufactured product, there are a few variables to consider. The sand should conform to ASTM-C144 requirements as well as to the requirements laid out in ICPI Tech Spec #9. Additionally, as polymeric sands have gained wide acceptance, look for a manufacturer that can point to years of proven results.