Shreveport Clay Soil and Your Foundation: Check Your Lot Before You Buy Piers
Northwest Louisiana isn't the worst place in the state for swelling soil. But some Shreveport lots sit on one of the most expansive clays researchers have tested. Here's how to find out which one you have.
First, a surprise: the statewide map
A 2021 study by LSU researchers, Mostafiz et al. (LSU), "Property Risk Assessment for Expansive Soils in Louisiana," Frontiers in Built Environment, 2021, mapped swelling potential across Louisiana. The highest values were in the southeast and the far southwest. Northwestern Louisiana had some of the lowest, and Caddo and Bossier ranked among the least vulnerable parishes.
So why do foundations still move here? The same study found expansive-soil property losses concentrated around Shreveport anyway, because that's where the buildings are. It also notes that montmorillonite clay in northern Louisiana has been particularly troublesome. A parish average is the wrong tool for one house. Your soil is the right one.
Meet the soil that causes trouble: Moreland clay
On the Red River floodplain, one soil comes up again and again. The USDA-NRCS Official Series Description: Moreland series describes Moreland as very deep, somewhat poorly drained and very slowly permeable, formed in clayey sediment carried down from the Permian Red Beds. Its profile lists "intersecting slickensides and pressure faces," the polished surfaces that form as clay swells and shrinks.
Louisiana Tech researchers tested it in Khan, Wang & Patterson, "A study of the swell-shrink behavior of expansive Moreland clay," International Journal of Geotechnical Engineering:
- Classification: highly expansive fat clay (CH)
- Liquid limit 79, plasticity index 51: it takes on a lot of water
- Average swell 7.2 percent, which the authors say ranks among the highest of expansive soils studied worldwide
Check your own lot in 10 minutes
- Open the USDA Web Soil Survey, search your address, and draw a box around your lot.
- Look at the soil map unit names. Note any clay series, and check whether Moreland is listed.
- Under soil properties, check shrink-swell (linear extensibility) for your map unit.
- Walk the house: doors that stick in one season and not another, stair-step cracks in brick, gaps at window frames, sloping floors.
The LSU paper lists the same symptoms of expansive soil movement: cracked foundations, walls, driveways and sidewalks, ruptured pipes, and doors and windows that won't open or close properly.
What the signs usually mean
| What you see | Likely meaning | Sensible next step |
|---|---|---|
| Hairline cracks that stay the same size | Often normal concrete shrinkage | Mark the ends with a pencil and date them. Watch |
| Doors stick in summer, free up in winter | Seasonal soil movement | Fix drainage and even out moisture. Then inspect if it gets worse |
| Stair-step brick cracks that are growing | Differential movement | Get an inspection. Possibly foundation repair |
| Water ponding against the slab after rain | A drainage problem feeding the clay | Drainage solutions |
| Bouncy or sloping floors on a raised house | Pier or beam movement | Pier-and-beam evaluation |
Repair options, honestly compared
The LSU authors list mitigation approaches used on expansive soils: pile support, void space under slabs, vapor barriers, and perimeter drainage that carries moisture away from foundations. They also point out that mitigation can often be done relatively easily. For an existing home, that usually means one of these:
- Water management first. Gutters, grading and drainage. It's the cheapest step and sometimes enough.
- Soil stabilization where moisture swings are the main problem.
- Piers, such as helical or push piers, when the slab has moved and needs support from deeper, more stable soil.
- Slab repair for localized damage.
What drives cost
Inspections and estimates are free. Repair cost depends on how much of the foundation has moved, slab or pier-and-beam construction, the number and type of piers, access around the house, and whether drainage work is part of the fix. Our pricing page explains how we quote. We'll tell you when drainage alone is the right first step.
What our inspection covers
We measure floor elevations, map the cracks, check doors and windows, look at grading and downspouts, and look up your lot's mapped soil. You get a written finding: monitor, fix drainage, or repair, with the reasoning. Licensed & insured, and available 24/7 for emergencies.
Shreveport soil and foundation questions
Is Shreveport really clay country?
It depends on the street. A 2021 LSU risk study using a statewide map ranked Caddo and Bossier among the least vulnerable parishes for swelling soils. But it still found expansive-soil losses concentrated around Shreveport because of how many buildings are here. And specific soils, like the Red River's Moreland clay, are highly expansive. Your lot's soil matters more than the parish average.
How do I find out what soil my house sits on?
Use the free USDA Web Soil Survey. Draw a box around your lot and it lists the mapped soil series. If you see Moreland or another clay listed as having high shrink-swell potential, take cracks and sticking doors seriously.
What makes Moreland clay so bad?
Researchers who tested it at Louisiana Tech classified it as a highly expansive fat clay, with a liquid limit of 79 and a plasticity index of 51. They measured an average swell of 7.2 percent, which they described as one of the highest values compared with expansive soils worldwide.
Do wet years or droughts cause more damage?
Both, and especially the swing between them. Expansive clay swells when wet and shrinks when dry. The LSU study notes Louisiana has seen more frequent wet and dry extremes, and Louisiana Tech researchers studied how severe drought affected expansive clays in northern Louisiana.
Every crack means I need piers, right?
No. Many small cracks are cosmetic. What matters is a pattern: cracks that keep growing, doors and windows that start sticking, floors that slope, or cracks that come back after patching. An inspection tells you which one you have.
What can I do myself?
Manage water. Keep gutters clean, send downspouts away from the slab, and make sure soil slopes away from the house. Keep soil moisture around the foundation as even as you can through the seasons. Those steps cost little and help on any clay.
Sources
- Mostafiz et al. (LSU), "Property Risk Assessment for Expansive Soils in Louisiana," Frontiers in Built Environment, 2021: statewide swelling map, parish rankings, Shreveport loss concentration, northern Louisiana montmorillonite, symptoms and mitigation.
- USDA-NRCS Official Series Description: Moreland series: Moreland soil properties and origin.
- Khan, Wang & Patterson, "A study of the swell-shrink behavior of expansive Moreland clay," International Journal of Geotechnical Engineering: Moreland clay classification, Atterberg limits and swell.
- USDA Web Soil Survey: free lot-level soil lookup.