Does polymeric sand let water through?
If polymeric sand is used in areas without proper drainage, then the water will expose the sand to prolonged periods of wetness and moisture, making it vulnerable to washout. In order for the polymers to harden, the water has to be able to escape.
Installing polymeric sand on a damp or wet surface could cause the sand and polymers to stick to the surface and become difficult to remove. After installation, a hard rain on polymeric sand that has not fully set up could result in polymeric sand all over the top of the pavers.
When watering in the Poly Sand, remember Goldilocks - "This is just right." Don't use too much or too little water. The amount of water you use is a critical element to an installation. Using too much water can cause the joint to over-saturate and result in polymer washout, mushy sand, and a weak bond.
1. Polymeric sand hardens quickly. This can be a benefit—you don't have to worry about it creating a mess that you can't get rid of, and it makes the finishing process simple. However, you should NEVER install polymeric sand when it is raining!
Over time, the sand in between paving stones will erode and begin to fade. For the DIY pathway, this means you will need to fix the pathway in as little as 1-2 years, depending on weather changes. Polymeric sand problems lead to the inability to replace any of the paving stones that have eroded or have damage.
No, the water does not drain through the sand around the pavers.
While each brand of sand will vary, Alliance Gator G2 Polymeric Sand with Rapid Set Technology is considered rainproof after 15 minutes at temperatures over 32° F degrees.
Most poly sands are considered “rain proof” after one hour, but I wouldn't bet the bank on that. You really want at least 24 hours of warm, dry air to ensure that the poly sand completely sets. Sustained dampness prior to setting may damage the poly sand to the point it will never set.
Weather Considerations For Polymeric Sand For PolySweep polymeric sand to set up properly, the temperature should be above 35 degrees for 24 hours before and 48 hours after installation. Plus, the surface needs to be dry at the time of installation and no rain forecasted for at least 12 hours afterwards.
Polymeric sand cures by drying. And in order to fully set, it needs to dry out completely. If your polymeric sand didn't harden up, it's pretty much guaranteed there's a moisture issue. If the joints remain wet after the installation, they will remain soft until they dry.
Can you pressure wash polymeric sand?
You can't pressure wash and apply polymeric sand on the same day. I should warn you that getting the stain off is a huge problem so it's best to take the time to avoid it in the first place.
Polymeric Sand needs a minimum depth of 4 cm (1 ½”) to be effective. Use a power washer to empty the joints. If there is already polymeric sand between the pavers, soak the sand to soften it up before emptying the joints.
Traditionally, concrete paver manufacturers have recommended waiting at least 90 days after polymeric sand installation to apply a protective sealant to a paver surface. Nowadays, a 30 day delay is sufficient to allow the evaporation of any remaining natural efflorescence contained in the pavers.
Most poly sands are considered “rain proof” after one hour, but I wouldn't bet the bank on that. You really want at least 24 hours of warm, dry air to ensure that the poly sand completely sets. Sustained dampness prior to setting may damage the poly sand to the point it will never set.
If polymeric sand is installed prior to sealing, be sure surface is dry for 24 hours before applying sealer.
Polymeric sand cures by drying. And in order to fully set, it needs to dry out completely. If your polymeric sand didn't harden up, it's pretty much guaranteed there's a moisture issue.