Polymeric sand in pavers and why we don’t use it.
We continue to get a lot of requests to use polymeric sand when cleaning and sealing pavers. Let me take a minute to cover why this is a bad idea.
Polymeric sand (also known as Polysweep, polybond and polysand and sandlock, along with other trade names,) was originally designed to be installed on new paver installations. If your look at the directions on the bag, It must be applied to a depth of more than 1 inch. On a new installation of thick pavers, that can be achieved. But on thin pavers or on a restoration project, it is impossible to get the old sand out to that depth unless the joints are 1/4 inch wide or more. How many pavers are installed with 1/4 inch joints? A few, but not many. If added after the initial installation, the directions say to sweep in the polymeric sand. Try to sweep dry sand into paver joints in Florida. It can take 5 days or more for the moisture in the joints to dry sufficiently for the sand to get down to the bottom of the joint and how many days has any part of the Tampa Bay area been with out rain or even heavy dew in the last couple years? If the polymeric sand does not get to the bottom, as soon as water is added to lock the polymers, it will collapse and you will have voids in the sand.
Polymeric sand manufactures claim it will stop weeds. It doesn’t. Sorry, but weeds will find any gap or void and take hold. I watched my neighbor install his own pavers. He was extraordinarily meticulous in his preparation and installation and the polymeric sand was applied perfectly-I watched every step, (I only wish professional installers would be so meticulous.) Within 6 months he had weeds! We continue to take out polymeric sand on a regular basis. Rarely is it good after 6months to a year.
Polymeric sand needs to be wet down to lock the polymers but often times too much water is added and the polymers float to the surface and stain the pavers. This can also happen because some manufacturers may add cement to the mix to cut down costs. The cement can also stain the pavers with a whitish or light gray film which the manufacturers then blame on efflorescence. See my article on efflorescence https://www.propaverseal.com/efflorescence-on-pavers/
This film is extremely difficult remove and the stains can be permanent. A couple examples:
Polymeric sand is made of pretty fine sand. Paver joints need a mixture of coarse and medium sand to allow complete filling of the joint. When the poly sand hardens it doesn’t expand to fill the joint, it just gets hard and over time, with expansion and contraction of the pavers, the hardened sand will just crack and crumble or even just pop out. It often just gets soft and attracts dirt as in the above picture.
Our process is to clean out the joints as much as possible, flush in course sand and seal with Seal Lock sealer which has additives to ‘lock’ the sand together in place. We will not use polymeric sand. SealNLock paver sealer does a better job at minimizing weeds and keeping the sand in the joints. Is it perfect? No. There are too many variables that work against the sand staying hard. Pavers move and shift, more so on driveways. But overall the stabilized sand is a big improvement from poor polymeric installations.
Watch our process here: https://www.propaverseal.com/