Fill Sand

Fill dirt is soil based, which means it can contain organic material that decomposes, shrinks, and leaves voids underground over time. It also holds water unevenly and swells or contracts with moisture changes, which can shift anything built on top of it. Fill sand is mineral material with no organic content, so it does not decompose or settle unpredictably once compacted. It also drains better than dense clay-heavy dirt, moving water through the fill rather than trapping it against a foundation or pipe. That makes sand the better choice anywhere you need predictable, stable support, such as around pipes, under pool walls, or against a foundation wall where moisture control matters. Dirt is usually cheaper and fine for rough grading far from structures, but once drainage, compaction, and long-term stability matter, sand is worth the extra cost. The tradeoff is that sand needs more careful compaction in lifts to perform well, rather than simply being dumped and left.

Start by removing loose debris, organic topsoil, and any soft or saturated material from the area to be filled. Add fill sand in lifts of 2 to 4 inches, not all at once. Lightly moisten each lift, since dry sand will not compact properly, then tamp with a plate compactor or hand tamper before adding the next layer. Expect roughly 10 to 15 percent volume loss as it compacts, so order extra to hit your final grade. For backfill around pipes or conduit, shovel sand carefully to fill voids on all sides before compacting, avoiding large air pockets. For pad or sub-base work, cap the compacted sand with the appropriate top layer, gravel for structural bases, soil for turf areas, since fill sand alone is not a finished surface in any of these applications.

Compared with mason sand. Mason sand is washed and screened to a fine, uniform grain for mortar and sandboxes, which costs more and performs well for finish work. Fill sand is coarser and unwashed, built for bulk backfill and grading rather than a clean finished texture.

Compared with fill dirt. Fill dirt is cheaper soil-based fill prone to shrinking, swelling, and poor drainage. Fill sand compacts predictably, drains moderately well, and will not break down over time, making it the better choice near foundations, pipes, and pools.

How much fill sand do I need. Multiply area in square feet by depth in feet, then divide by 27 to get cubic yards. As a reference, 1 cubic yard covers about 162 sq ft at 2 inches deep or 108 sq ft at 3 inches deep. Add extra for the 10 to 15 percent volume loss expected after compaction, and remember delivered tons will vary with moisture content.

How fill sand is sold and delivered. Fill sand is sold in bulk by the cubic yard or by the ton, with delivery sized to the project, from small trailer loads to full dump truck quantities for larger grading and backfill jobs. Because it is unwashed, exact color and fines content can vary slightly between loads depending on the source pit.