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Do You Wet Sharp Sand Before Compacting?

Any aggregate material used as a sub-base must be compacted and levelled to carry weight successfully. Smooth, granular materials generally take to compaction best, though even coarse aggregates can be levelled with a little help. Today we’ll look into this by asking, do you wet sharp sand before compacting? 

We’ve performed hundreds of paving installations over the last 15 years, working with just about every kind of aggregate you could imagine. Of all these materials, we’ve found that sharp sand can be one of the trickiest to fully compact, though that’s not to say it can’t be done.

It’s a good idea to wet sharp sand before compaction as this material’s rough grains don’t align too easily without a bit of lubrication. Applying some moisture to sharp sand helps to fill the spaces between the grains, allowing them to settle in a more uniform pattern.

Sand Compaction Methods

Plate compactors

One of the most common tools professionals use to compress sand is the vibrating plate compactor, AKA a mini wacker plate. These machines use a large, vibrating metal plate to force granular materials like sand and soil into a level and uniform foundation.

Though plate compactors work best on smooth-grained materials, applying a little water to a sharp sand sub-base can help a wacker plate to perform better. Just sprinkle some water over the sand and run the plate compactor over the surface a few times in straight lines. People also ask what is better a plate compactor or jumping jack, take a look through this guide and decide for yourself.

Manual rollers

Manual rollers are a cheaper alternative to wacker plates but is a roller better than a wacker plate? These devices feature a large cylinder filled with a heavy material (usually sand or water) that can be rolled over an uneven patch of sand to compact the grains into a much smoother, levelled surface. 

Manual rollers work well on rough-grained materials as their rolling cylinders cover a fairly large surface area. This allows for an even distribution of weight which can help to better smooth out coarse materials like sharp sand.

Hand-tamping

Hand-tampers are perhaps the most basic sand-compacting tools, consisting only of a flat metal plate attached to a long handle. Using a hand-tamper to compact sand is as simple as walking atop the surface and pressing down on the sand to compress the grains together. 

It’s a good idea to rake your sand and sprinkle water over the surface before hand-tamping. This will aerate the material and lubricate the voids between the grains, making it much easier to press down into the sand to form a uniform foundation.

Sand Compaction With Water

To achieve the best results when compacting sand with water, you’ll want to rake the surface first and then sprinkle a small amount of water on top of the sand from your garden hose.

Use too much water and the grains won’t pull together, resulting in a waterlogged surface that won’t take well to compaction, so make sure that there are no visible puddles above ground.

Leave the sand for around an hour to allow the water to drain through the material, then begin to lightly tamp the ground with a hand-tamper or by simply walking over the surface. Once this first round of tamping is done, you can fully compact the area using a wacker plate or roller.

Tips For Compacting Sand Wet Or Dry

  • Rake/aerate the sand
  • Allow surface water to drain below the top-layer 
  • Manually tamp first using a hand tamp or by walking over the surface
  • Vibrating plates work best with smooth, granular sands
  • Rollers work well with coarse sands
  • Work in straight lines when using a wacker plate or roller
  • Cover the entire area twice for adequate compaction

FAQ’s 

Do you wet the ground before tamping?

In most cases, yes, a little moisture will help with tamping, though too much moisture can be a problem. Always allow any surface water to drain below the surface before you begin tamping.

Does sand harden when wet?

Some specialised paving sands (polymeric sand) will harden when exposed to water, whilst standard sands will temporarily appear a little harder once dried. However, they won’t permanently set due to moisture alone.

Last Word

We hope this guide has helped you learn how to successfully compact sharp sands. Whilst these coarse materials can be a little challenging to work with, using the right tools and methodologies can help to perform successful compaction. 

Remember to aerate the sand, apply a little water to help lubricate the material, and manually tamp the surface before finishing it off with a roller or wacker plate. Following these steps should leave you with a nice, level sandy sub-base!