No, leveling sand does not harden. Its primary characteristic is that it remains loose and granular, making it susceptible to displacement by water or strong forces.
Leveling sand, often referred to as bedding sand or screeding sand, is specifically used to create a flat, stable base for various landscaping and construction projects, such as beneath pavers or artificial turf. Unlike materials like concrete or polymeric sand, it does not contain binders that react with water or air to solidify.
Why Leveling Sand Doesn't Harden
The nature of leveling sand is that of unbonded, individual grains. This property is both its advantage and its limitation:
- Composition: It typically consists of fine, sharp aggregates that compact well under pressure but do not fuse together.
- Water Permeability: It is highly permeable, allowing water to drain through it readily. However, this also means that water, especially from rain or a hose, can cause it to "wash out," as noted in the reference: "No. It tends to wash out when it rains or if you hit it with the hose." This confirms its non-hardening nature and susceptibility to erosion.
- Flexibility: Its unhardened state provides a flexible base that can slightly shift and settle with the ground, which can be beneficial for some applications but detrimental for others if not properly maintained.
Practical Implications for Paver Installation and Maintenance
The non-hardening nature of leveling sand has significant implications for its use, particularly in paving projects:
- Periodic Replenishment Required: Because it washes out, continuous maintenance is necessary for areas using leveling sand as joint filler or base material. The reference explicitly states this need: "That's why you need to spread fresh sand over the pavers and sweep it in the gaps periodically."
- Erosion and Weed Growth: Over time, the sand in the joints of pavers can erode, leading to wobbly pavers, weed growth, and insect infestations.
- Maintaining Stability: Regular sweeping of fresh sand into the gaps helps maintain the interlock and stability of the paver system.
Comparing Leveling Sand with Hardening Alternatives
To better understand why leveling sand doesn't harden, it's useful to compare it with materials designed to do so:
| Feature | Leveling Sand | Polymeric Sand | Concrete/Mortar |
|---|---|---|---|
| Hardening | No (remains loose) | Yes (activates with water to harden) | Yes (hardens permanently upon curing) |
| Erosion | High susceptibility to washing out | Low; forms a durable, erosion-resistant joint | Very low; forms a rigid, monolithic structure |
| Flexibility | High (can shift and resettle) | Low (creates a semi-rigid joint) | None (creates a rigid, inflexible bond) |
| Maintenance | Requires periodic reapplication | Minimal; long-lasting | Minimal once cured |
| Primary Use | Bedding layer, joint filler (traditional) | Paver joint stabilization, weed/insect control | Structural foundations, permanent paving, bonding |
For projects where stability and minimal maintenance are crucial, especially in paver joints, alternatives like polymeric sand (which contains polymers that bind the sand grains together when wet) are often preferred over plain leveling sand. However, for initial leveling layers beneath a surface, plain leveling sand remains a cost-effective and easy-to-work-with option.
