Polysand, short for Polymeric Sand (aka Polymer Sand) is a relatively newcomer on the landscaping scene. It is typically used for interlocking pavers in place of concrete sand. What is it and what’s so great about? Here at Triton Landscaping we do a lot of repair work as well as new installs with interlocking pavers and so this is a topic many of our homeowners are interested in. Here’s our take.
In the 1980s, chemists and materials engineers were experimenting with adding polymers, that is plastics, to long used compounds of concrete and cement. It was found that the polymers significantly increased the tensile strength of these materials, that is its ability to resist being pulled apart. This is the origin of modified thinset mortar as covered here.
Along the same lines of thinking, materials engineers also experimented with adding polymers to concrete sand, long used in the interlocking pavers and landscaping industries and used to this day. They started appearing as a commercial product in the late 90s early 2000s.
The main difference between its application and that of traditional and time tested concrete or joint sand is that it is activated by moisture. As soon as moisture hits the polymeric elements within the mixture, a chemical reaction starts that bond the sand together into a more unified mass. Whereas with regular concrete sand, which is also bone dry when applied, a little moisture is tolerable as it just makes the sand a bit clumpy and sticky, it will absolutely ruin polysand. This is the same reason that once you add moisture to cement, concrete, and mortar, you can’t just turn back the clock or put a freeze on it. It has to be applied now. It’s the same line of processes that prevents you from unboiling an egg.
This means that in our wet winters in Victoria BC, it is very difficult to find a window to apply polysand as any moisture will immediately activate the compound before it’s finished applying.
According to manufacturers, the correct way to apply polysand to pavers is to sweep the sand into the paver joints just as one would do with regular concrete joint sand. This has to be done while the entire surface including the joints themselves are totally dry. Problems arise including premature activation but also stains if the paver joints or surface is wet. In fact, stains is the number one reason many landscapers in Victoria BC and elsewhere do not use polysand and stick to regular joint sand.
After the sand is swept into the paver joints, a plate compactor is used to vibrate the sand into place as well as the pavers themselves. Usually this will mean crevices will appear between some of the joints. The landscaper will then apply more sand to fill those joints. At this point, any excess sand must be removed.
During all these steps, the entire surface must remain bone dry. Otherwise you will have stains on the pavers as well as unsightly clumps and materials that won’t bind the pavers in the joints. When the second sweep of sand has been done and all excess removed, the area is lightly sprayed with a hose to activate the compound. Any excess sand missed during this process will likely stain your pavers.
Polymeric sand costs more than 3 times as much as regular joint sand. Polymeric sand has been heavily pushed and advertised in the landscaping industry here in Victoria BC and all over North America. Someone has to pay for the advertising campaigns and it ends up being the consumers of course.
Is it Worth It?
If you talk to a lot of landscapers, especially ones who have been doing this for 30 40 years, they will say no. Besides the problematic application process, especially with our unpredictable wet weather here in Victoria BC, it’s more than triple the cost of regular joint sand. Regular joint sand is tried and tested, is far more versatile in its application, and will not stain your brand new pavers.
Does it Prevent Maintenance Problems?
If you ask some people they will swear that it prevents weeds and ants from burrowing into the joints. If this were consistently true, it could very well justify the extra difficulties in application and the extra costs. The problem is that if you spend time asking various people who have been doing this for a long time, it’s clear that there is no clear consensus on its actual efficacy. Regular joint sand, when applied properly, should last years and is easy to top up and cheap. Unless polymeric sand lasts three times as long or more on a consistent basis, is it really worth the extra cost and risks during application?