Polymeric sand isn't strictly required, regular jointing sand will hold pavers in place too, but polymeric sand is usually worth it because it hardens in the joints, resists washout, and does more to block weeds and ants than plain sand does. Whether it's necessary depends on the site's drainage, slope, and how much maintenance the owner wants to do.
The difference comes down to a binder mixed into the sand that activates with water and hardens the joint once it's set, rather than staying loose like regular sand does. On a flat, well-shaded patio with light traffic, plain sand can hold up fine for a long time. On a sloped patio or one that gets a lot of runoff, plain sand tends to wash out of the joints faster, which is exactly where polymeric earns its keep.
Polymeric sand has a tradeoff, it needs to be installed correctly. It has to be swept in dry, activated with the right amount of water, and given the right weather window to cure, or it can haze on the paver surface or fail to bond properly. That makes it less forgiving than plain sand if the installation isn't done carefully, which is part of why the choice matters as much as the product itself.
We recommend jointing material based on the actual site, slope, sun exposure, expected traffic, rather than defaulting to the same product on every job. Some patios genuinely don't need polymeric sand to hold up well, and we'd rather tell an owner that than sell an upgrade that isn't going to make a real difference on their particular patio.
More on this from Chelo's Brick & Stone.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
