There is a soft, sinking spot in your artificial turf. Here is what is under it.

Turf sits on a few inches of compacted crushed stone. When that stone stays put, the turf stays firm. It stops staying put for three reasons.

• Settlement. Base laid over fill dirt, over a trench for irrigation or a utility line, or compacted in one pass instead of several, keeps settling for a year or two after the install. The spot is low and firm rather than hollow, and it usually shows up in the first two summers.
• Washout. Water moving under the turf carries the fines out of the base. A downspout that discharges onto the turf, a leaking irrigation line under it, or runoff from a patio edge will hollow out a channel. Coastal Plain sand moves easily once water is running through it, which is why Grand Strand yards wash out faster than yards on clay.
• Tunnels. Moles, voles, armadillos and fire ants all work under turf. Moles leave a soft raised line you can follow with your foot. Armadillos leave a shallow bowl near a bed or a fence. Fire ants push a mound of loose soil up against the backing, usually in spring and fall.

Walk the spot in flat shoes and mark the outline of where it gives. Then push a long thin screwdriver or a length of steel rod straight down through the turf between the fibers. The backing is perforated for drainage and a small probe hole does no harm.

1. Firm resistance within an inch, but the spot is lower than the turf around it. Settlement. The base is there; it has dropped.
2. The probe goes several inches with no resistance. A void. Water or an animal has removed the base and the turf is bridging air.
3. A soft line that continues in a direction. A tunnel. Follow it to find where it comes up.

Then look for water. Trace the downspouts, run the irrigation and listen for a hiss under the turf, and note whether the spot is on the low side of a patio. A void with a water source is a washout, and the water has to be fixed first or the patch will hollow out again.

A single soft spot smaller than a card table, especially near an edge, is a repair. We lift the nearest edge or open a seam, pack the void with base material in layers, compact it, re-lay the turf, re-secure the edge and re-level the infill. That is a turf repair, from $250, and if it only needs an edge lifted it is closer to the edge repair price of $175. A tunnel gets the same fill after the animal is dealt with; a fire ant mound is treated first, then the loose soil is cleared and the base packed.

A spot that has kept sinking for two years, several soft areas across the yard, a whole section that sits lower than the patio, or turf that was laid on dirt with no stone base at all is not a patch. That is lifting the turf and rebuilding the base, which is install work our sister company does. We tell you which on the inspection rather than sell you a patch that will not hold. Standing water in the low spot is the same conversation, and our page on pooling covers how to read it.

Nearly every washout we see has a downspout, a hose bib or a sprinkler line behind it. Extend downspouts past the turf. Cap irrigation heads that throw onto it; turf does not need water. After a tropical storm, walk the yard and press the low spots, because that is when a base moves. Treat fire ant mounds when you see them rather than mowing around them the way you would on grass. Every Premium Restoration includes an edge and seam inspection, and we will point out a soft spot before it becomes a hole.

Call us when a soft spot is bigger than your hand, when it is getting bigger, or when the probe goes in with no resistance. Repairs start at $250; edge re-securing from $175. If it is a rebuild, we say so and refer it.