5 Expert Tips For Compacting Native Soil

Proper compaction of the sub-grade and base material is key to a successful hardscape design. In this blog post, we’re going to share five expert tips for compacting your sub-grade or native soil.

1. Know what you’re working with.

Before beginning your project, identify the type of native soil you’re working with. Make sure that it’s suitable for supporting the expected load, whether pedestrian or vehicular. Highly organic soils need to be removed and clay soils may need to be removed or amended.

2. Amend (if needed).

Amending clay soils can be done with:

• Portland cement

• Larger clean stone compacted into the clay

• A combination of the above

3. Check moisture content.

Granular soils should have a certain moisture content for proper compaction. Moisture will lubricate the particles and help them slide into place.

4. Use the right compaction equipment.

First, make sure your compactor is large enough for the job. Then make sure you use the right type of compactor. Vibratory plate compactors are appropriate for granular soil types, but jumping jacks or sheepsfoot rollers are necessary for clay soils. Native soils should be compacted to 98% Proctor Density.

5. Don't reuse excavated materials.

It’s important to never put excavated materials from a site back into the hole. Once soils are excavated they fluff by 20-30% and are usually unsuitable for compaction back to their original density.

A Final Piece of Advice

Follow these five pieces of advice and you’ll be in good shape for the remaining phases of your project. If you find your soil is substandard or questionable, consider using a geotextile fabric to add an additional layer of strength!