Due to heavy traffic loads, extreme weather effects and the consequences of cleaning using vacuum sweeping machines, the joints of paved stone surfaces can start to have weak areas that crack and break out, leading to empty joints and dislodged paving stones, making it dangerous to walk on. Maintaining old paver joints reverses the damage, helps enhance paved surfaces and makes them safe for foot traffic once again.

As an example, two very popular areas in the U.S. with high traffic demands, Las Vegas Boulevard, and the 16th Street Mall in downtown Denver, are receiving continuous maintenance using materials from ROMEX?????????????(R)???????+???? PFM GmbH, a manufacturer of synthetic resin paving jointing mortar.

According to customer service director Stephanie Goodwin, the company's ROMPOX?????????????(R)???????+???? D1 and D2000 products are being used daily in Las Vegas, in an area called "The Park," by subcontractors hired by MGM Construction and trained by the manufacturer's representatives.

And in Denver, small closures in the mall occur almost nightly and D2000 is installed to keep up with the ongoing damage caused by vehicular, bicycle and pedestrian traffic, and freeze and thaw cycles.

"For instance, right now we are working in Vancouver at a university and there are weather conditions," says Goodwin. "It drops below zero unexpectedly. Or in downtown Denver, the guys can only work at night because they can't just close down a major street so these COOs give them key advice on how to do it."

The company's product catalogue states, "as soon as weak areas have formed, action needs to be taken quickly because shear forces create a domino effect, which destroys adjoining, still intact paver stones."

To prepare existing joints for repair, the catalogue recommends using high air pressure, a water jet or specialty equipment to achieve the desired joint depth (1 3/16" or for high load bearing areas, at least 2/3 of the height of the stone). In general, the deeper the jointing mortar is laid, the more stable the entire construction will be.

Once the joints have been blown clean, any litter, weeds, roots, stone or cement residue should be removed. And the stones themselves should be free of oils, grease and paint.

After this has been completed, if any individual paving stones wobble when walked on, the joints have been cleared out too deeply. These then need to be completely fixed or full joint bonded before jointing is carried out.

When the surface is ready for mortar application, it first needs to be wetted. Then the mixed mortar is worked carefully into the joints using a squeegee-type tool. After approximately 10 minutes (at a surface temperature of 68?????????????(R)???????+?F), the excess mortar on the surface of the stones can be swept off carefully, diagonally to the joints, first with a large, coarse broom, then with a soft, hair broom until all residual mortar has been removed. Finally the paved surface should be gently sprayed then swept again with a wet hair broom.