Does sandy soil shrink and swell like clay?

No. Sand is not meaningfully expansive, so it does not lift and drop a home seasonally the way clay does. Sand causes settlement through low bearing capacity when loose and through erosion when water runs through it.

What is pad punching?

Punching is when a pier pad drives down into loose soil instead of spreading its load across it. The grains rearrange under pressure and the pad descends until the material beneath is dense enough to stop it.

How can I tell scour from punching?

A punched pad usually sits in a depression with soil mounded around it. A scoured pad often stands proud of the surrounding ground with a channel or a fan of washed sand nearby, and it tends to be near a downspout or a low point.

Will a bigger pad fix the problem by itself?

It addresses punching. If water is scouring soil from around the pier, the water path has to be corrected as well or the new pad will be undermined the same way.

Deep Sand and Pier Pad Settlement

The soil under most homes around Palestine

Anderson County is not one soil. The western part of the county falls in the Texas Claypan area and is used mainly for pasture. The eastern part is East Texas Timberlands. Close to half the county's soil belongs to the Fuquay, Kirvin and Darco group, which is deep, sandy and loamy, and Darco in particular is a very deep sand.

If you have read anything about foundation problems in Texas, most of it was written about expansive clay. Clay takes on water and swells, dries out and shrinks, and that cycle moves whatever is sitting on it up and down through the year. Homeowners on clay learn to expect doors that stick in one season and swing freely in another.

Deep sand does not do that. Sand is not meaningfully expansive. It does not lift your home in spring and drop it in August. Anybody applying clay framing to a home on Darco sand is describing a mechanism that is not happening under that house.

How sand actually fails

Sand has two vulnerabilities that clay does not share to the same degree.

1. Low bearing capacity when loose

A sand deposit is a pile of grains held together mostly by friction between them. When those grains are densely packed, the deposit can carry significant load. When they are loose, as surface sand and freshly placed fill usually are, the grains can rearrange under pressure. Put a heavily loaded pad on loose sand and the grains beneath it shift and compact, and the pad moves down until the sand under it is dense enough to stop it.

That is punching. From above it looks like nothing happened. The pad is still flat, still intact, still in the right place. It is just lower than it was, and so is the corner of the home resting on it.

2. Movement by erosion

Sand grains are loose, roughly uniform, and easily carried by moving water. That is why you see clean sorted sand in the bottom of every ditch in East Texas after a hard rain. Under a home, running water does the same thing. Roof runoff with no gutters, a driveway shedding toward the home, a low spot that channels sheet flow beneath the crawl area, or a slow supply line leak will all move sand.

The distinctive thing about scour is that it undermines a pad without disturbing it. Water carves out material beside or beneath one edge, and the pad ends up bearing on a smaller area than it was designed for, or overhanging a void. Then it tips.

What punching and scour look like in practice

Signs of punching

A pad sitting in a shallow depression, with soil slightly mounded around its edges.
One pier noticeably lower than the ones on either side of it along the same beam.
A gap between the pier cap and the steel beam, or shims that have gone loose.
Settlement concentrated at heavy points: near the marriage line, under a fireplace, a tub, or a large appliance run.
Repeat settlement at the same location after a previous leveling that only reset shims.

Signs of scour

A fan or small delta of clean, sorted sand near a pier or at the skirting line.
A pad standing slightly proud of the surrounding soil, with soil washed away beside it.
A visible channel or rill running under or alongside the home.
One pier dramatically worse than every other pier, usually the one nearest a downspout or a low point.
Anchor heads that look more exposed than they used to.
Damage that gets noticeably worse in the weeks after a heavy rain event.

Why pad size matters more on sand

A pier pad exists to spread the load from the column over enough ground area that the pressure on the soil stays inside what the soil can carry. Pressure is load divided by area. Halve the pad area and you double the pressure on the soil beneath it.

On a firm, dense soil, an undersized pad may have enough reserve capacity that nothing visible happens for a long time. On loose deep sand, there is much less margin. The pressure exceeds what the sand can carry, the grains rearrange, and the pad moves. It is not a dramatic failure. It is a slow, quiet descent measured in fractions of an inch, and the first thing anybody notices is a door that stopped latching.

There is also an important asymmetry: going up a pad size on the way in is a small cost, while coming back to lift and rebuild the same pier in three years is a large one. On sand the conservative choice pays for itself.

What a contractor should be evaluating

Actual load per pier. Loads are not equal across a home. Piers near heavy point loads need more bearing area than piers in a light span.
What the pad is bearing on. Loose surface sand, compacted material, or uncompacted fill pushed in during site prep are three very different situations.
Depth. Getting below the loose surface layer to firmer material beneath makes a real difference on sandy sites.
Pad type. Precast pads, poured footings and engineered products behave differently, and the right answer depends on load and site.
Pier count. Sometimes the honest fix is more piers, so each one carries less.

Water control is half the repair

If scour caused the failure, rebuilding the pier without changing the water is a temporary repair. The same rain will follow the same path and do the same thing to the new pad. A durable fix on a sandy lot usually includes some combination of:

Grading so the ground falls away from the home on all sides.
Gutters with downspouts discharging well away from the perimeter.
Redirecting driveway and pad runoff so it does not head toward the home.
A swale or drain line where upslope water is reaching the crawl area.
Repairing any plumbing leak that is keeping the ground wet.
Skirting detailed so it does not trap or channel water rather than shed it.

How to check your own home

Walk the interior and note every door that rubs or will not latch, and which corner of the frame it binds at.
Set a marble or a level on the floor in several rooms and note the direction of slope.
Look for new cracks where interior walls meet the ceiling, and for gaps opening at the marriage line of a double wide.
Walk the outside and check whether the skirting line is even or bowing on one side.
If you can safely get a look under the home, check whether every pier is in contact with the beam and whether any pad sits in a depression or stands proud.
After the next hard rain, look for fresh sand fans and new channels around the home.

What you find tells a contractor a great deal before they arrive. A single low corner with a depressed pad points to punching. A single bad pier next to a downspout with washed sand around it points to scour. A whole end of the home that eases down in wet weather and firms up in dry weather points somewhere else entirely, most likely toward the claypan side of the county.

The bottom line

Sand is not a bad soil to build on. It drains well and it does not swell. But it is unforgiving of two specific mistakes: pads too small for the load, and water allowed to run where it should not. Get those right and a home on deep sand around Palestine can sit quietly for a very long time. Get them wrong and you will be releveling the same corner over and over.

Deep Sand and Pier Pad Settlement in Anderson County