Most polymeric sand installation mistakes happen in the few hours between sweeping the first bag and turning off the hose. A damp surface, a shallow joint, sand left on the paver face or the wrong amount of water can leave you with haze, soft spots or joints that crack and wash out. The good news is that each of these problems is spelled out, and avoided, in the manufacturers' own instructions.
Below are the polymeric sand installation mistakes that manufacturer data sheets warn about, grouped by stage, with the fix for each. Read the instructions on your bag and the data sheet for your product before you start, because watering methods and weather limits differ from brand to brand.
Key takeaways
- Install only on completely dry pavers and joints, inside the temperature range and rain window on your data sheet.
- Compact the pavers and the sand, fill joints to their full depth (commonly 1-1/2 in minimum), and leave the sand about 1/8 in below the paver surface.
- Clean the surface before watering, unless your product's instructions say otherwise.
- Water exactly as the bag directs: too little water leaves the sand under activated, and too much can lengthen curing or wash sand out.
- Keep vehicles, pressure washers and sealers off new joints for the time the data sheet specifies.
Polymeric sand installation mistakes before the sand goes down
1. Starting on damp pavers or joints
Alliance warns that a damp or wet paver surface makes the sand activate early and the polymers stick to the paver face, and that damp joints stop the sand from sliding in and packing densely. SRW says to wait 24 hours after rain before applying SimplyTough or X-Treme. Fix: wait until the pavers, joints and sand are completely dry, and turn off sprinklers.
2. Skipping compaction
Techniseal says mechanical compaction is mandatory for SmartSand, HP NextGel and NextGel Porcelain, and that failing to compact may compromise joint integrity. It adds that a properly compacted joint does not allow a finger to sink into it. Fix: run a plate compactor with a pad or protective plate over the field, top up the joints, and compact again. For natural stone or porcelain, SEK and SRW call for a vibratory roller or a rubber mallet instead. If you cannot compact at all and joints are wider than 1/4 in, Techniseal recommends Techniseal NOCO.
3. Joints that are too shallow
Most polymeric sands we carry specify a 1-1/2 in minimum joint depth. Exceptions include SEK PolySweep X-Treme at 1-1/4 in and Techniseal NextGel Porcelain at 3/4 in. Fix: when regrouting, remove the old material to the depth your product requires without disturbing the bedding layer.
Mistakes while filling the joints
4. Overfilling or underfilling
Alliance, Techniseal and SEK all specify a finished sand level at least 1/8 in below the paver surface or the bottom of the chamfer. Alliance says a joint filled higher than that may erode, and Techniseal says failing to recess the joint could lead to premature degradation. Fix: fill, compact, refill, then set the height with the broom or blower.
5. Leaving sand on the surface
Alliance's reference guide says white haze comes from excess polymeric sand residue left on the pavers when watering. SEK describes blowing the surface clean with a leaf blower held close to parallel, and SRW uses a blower on idle. Alliance's G2 sands are the exception, with no blower needed; their instructions call for a hard bristle broom followed by a soft bristle broom. Fix: follow your bag's cleanup sequence, and use the right sweeping and cleanup tools.
6. Mixing products or sweeping over asphalt
Techniseal says not to mix its sands with cement, sand or any other material, and Alliance says not to use its G2 sand with other materials in the joint. Alliance, Techniseal and SRW also say not to sweep their sands over asphalt, which SRW notes may stain.
Watering mistakes
7. Using too much water
Techniseal says overwatering HP NextGel will significantly lengthen curing and may compromise performance. SEK warns against applying water so fast that it floods the pavement or erodes sand from the joints. A jet setting on the nozzle makes both problems worse. Fix: use a shower or mist setting, such as a multi pattern watering nozzle, and start at the low end of the slope, as Alliance and Techniseal both direct.
8. Using too little water
Alliance says too little water will not properly activate its sand and will reduce final performance, and SEK says the entire joint must be fully saturated. Each brand describes the amount differently:
- Alliance G2 sands: shower for at least 30 seconds per 30 sq ft, or until the sand repels water and it starts to sit on the joints.
- Techniseal HP NextGel: shower a 200 sq ft section for 10 to 15 seconds, then again for 30 seconds, and check that at least 75% of the joint depth is activated.
- SEK PolySweep: mist no more than 500 sq ft at a time, let it absorb for about 5 minutes, and repeat 3 to 4 times.
- SRW X-Treme: water each section of up to 100 sq ft for a total of 2 minutes, then check for moisture at least 1 in deep with a screwdriver.
Weather and timing mistakes
Installing outside the product's temperature range or before a storm is a common cause of failure. The limits vary widely, so check yours:
| Product | Temperature | Rain |
|---|---|---|
| Alliance Super Sand G2 and Maxx G2 | Above 32°F | Rain safe 15 minutes after activation (traditional base) |
| Alliance Dust Bond | Above 59°F | No rain forecast for 24 hours |
| Techniseal HP NextGel and SmartSand | Above 32°F for 48 hours | Withstands unexpected rain after 60 minutes; needs 24 hours or more to dry |
| Techniseal NOCO | Above 50°F for 48 hours | Protect from rain for 24 hours |
| SEK PolySweep | Average above 35°F for 48 hours | No rain forecast for 12 hours |
Timing mistakes also happen after installation. Techniseal lists vehicle traffic at 48 to 72 hours for HP NextGel, SmartSand and NOCO, and restricts high pressure washers for 30 days. Before cleaning and sealing, Techniseal says to wait at least 7 days for HP NextGel and NOCO and typically 30 days for SmartSand, and SRW says 28 days for X-Treme.
Choosing the wrong sand for the joint
A sand used outside its rating is set up to fail. SmartSand tops out at 1 in joints, SRW X-Treme is not recommended for concrete pavers, clay pavers or overlays, and SimplyTough is not for clay pavers. Alliance Dust Bond and SRW X-Treme are for pedestrian use only. Check the width, surface and traffic ratings in our polymeric sand comparison, and read the full instructions in our TDS and SDS library. For a general purpose option on pavers up to 2 in, Alliance Gator Super Sand G2 is rated above 32°F and rain safe 15 minutes after activation.
A quick preinstallation checklist
- Forecast checked against the data sheet's temperature and rain window.
- Pavers, joints and sand completely dry; sprinklers off.
- Edges restrained and pavers compacted.
- Joints cleaned to the required depth.
- Enough sand on hand. Our polymeric sand calculator estimates bags from your joint width, depth and area.
- Broom, blower, compactor pad, rubber mallet and a hose nozzle with a shower setting ready.
Frequently asked questions
Can you put new polymeric sand over old sand?
No. Alliance's instructions for existing surfaces say to remove the existing jointing material first, then install the new sand at least 1-1/2 in deep into dry joints.
What happens if you skip the plate compactor?
The sand may not pack densely, which can leave soft spots and voids. Techniseal says skipping mechanical compaction with SmartSand or HP NextGel may compromise joint integrity.
Can you install polymeric sand in cold weather?
Only within your product's range. Alliance's G2 sands work above 32°F, Techniseal NOCO needs above 50°F for 48 hours, and Alliance Dust Bond needs above 59°F.
How long should you wait before walking or driving on new joints?
It depends on the product. Techniseal allows pedestrians immediately on HP NextGel and SmartSand, with vehicles after 48 to 72 hours. Alliance says to minimize walking on Dust Bond for 24 hours.
Why do new polymeric sand joints crack or crumble?
The usual causes in the data sheets are shallow joints, joints filled too high, too little water during activation, rain before the sand could set, or a base that moves.
Want to get it right the first time? Browse our polymeric sand collection or call (856) 418-4895, 24/7, and we will walk through your joints, surface and forecast with you before you order.