Why water is a foundation problem
The LSU AgCenter describes Louisiana’s heavy clay soils as swelling when they are wet and cracking open when they dry — the kind of movement that makes building foundations difficult.
A foundation sitting on soil like that is only as stable as the moisture around it. Water that pools against one wall and not the others soaks one side of the house; a yard that drains toward the house rather than away from it keeps the ground wet where the house needs it steadiest. Fixing the structure without fixing that is how a repair ends up being done twice. More on the soil side in clay soil and foundation movement.
Start at the roofline
The LSU AgCenter’s guidance on water-managed foundations starts with keeping rainwater away from the house. In practice the first places to look are simple:
- Gutters that overflow, sag, or are missing along part of the roof.
- Downspouts that empty right at the foundation instead of carrying water away.
- Flower beds, walks, or soil that slope toward the wall rather than away from it.
- Low spots in the yard where water stands for a day or more after rain.
Walk the outside of the house during a hard rain — or right after one — and take photos. Those pictures tell a specialist more about your drainage than anything you can describe on a dry afternoon.
Grading and downspout extensions
The same LSU AgCenter guidance calls for the ground around the house to slope away from the foundation. Regrading, extending downspouts, and adding splash blocks or buried downspout lines are the simpler corrections — worth asking about before anything is dug.
French drains
Where surface fixes are not enough, a French drain collects water underground and sends it somewhere else. It is a trench filled with gravel or rock, usually around a perforated pipe, that intercepts surface water and groundwater and carries it away from the area it is protecting.
Published Shreveport ranges put French drains at $24 to $37 per linear foot. Because the price is per foot, length is the biggest variable — here is how the published range scales:
| Length | Computed from the published range |
|---|---|
| 40 feet | $960–$1,480 |
| 60 feet | $1,440–$2,220 |
| 100 feet | $2,400–$3,700 |
These are arithmetic, not quotes. A drain’s route, its depth, and where it discharges — the street, a lower part of the yard, a dry well — all need to be written on the quote.
Under a raised house: the crawl space
On a pier-and-beam house, water does not have to reach the walls to cause trouble — it only has to get under the floor. The LSU AgCenter links ground moisture to decay, mold, and high humidity in the floor system, and recommends covering the crawl-space ground with plastic sheeting to block moisture from rising. It also advises keeping the ground inside the crawl space from sitting lower than the yard outside, so rain does not pond under the house.
Repair guidance for raised foundations adds vapor barriers and ventilation, and names leaks from plumbing as another source of crawl-space water. If you can see standing water, damp soil, or white growth on the wood under your house, mention it when you call. For the structural side of a raised house, see pier and beam foundation repair.
Why drainage gets its own line
On a properly written foundation quote, drainage is the second of four lines — separate from the structural work, so you can see exactly what is being done about the cause:
- 1Evaluation findingsWhat was measured and found — elevation readings, crack locations, construction type, likely cause.
- 2Drainage / moisture correctionGutters, grading, downspouts, or crawlspace moisture work that addresses why the soil is moving.
- 3Structural repairPiers, shims, or sill and beam replacement — with counts, locations, and depths stated.
- 4Finish / cosmeticDrywall, brick, trim, and door adjustments after the house moves — priced on its own line.
If one bid includes drainage and another does not, they are not the same job, even if the structural lines match. If a crack is what brought you here, the foundation crack repair page explains how to tell whether water is part of its story.
Published ranges
| Job | Published range | Scope | What moves it |
|---|---|---|---|
| Minor crack repair & basic waterproofing | $1,900–$3,800per job | Shreveport | Crack count and length, and whether moisture work is included. |
| French drain | $24–$37per linear foot | Shreveport | Length, depth, and where the water is sent. |
Rows marked “Shreveport” come from published Shreveport cost guides. These are published ranges, not quotes and not our prices — we do not price or perform work. A real number comes only from a specialist evaluating the house.
Permits. Ask your specialist who pulls the permit.
Drainage questions
What does a French drain cost in Shreveport?
Published Shreveport ranges put a French drain at $24 to $37 per linear foot. A 60-foot run works out to about $1,440 to $2,220. Depth, the route around the house, and where the water is discharged move it within that range.
Can drainage work fix a foundation by itself?
Drainage does not lift a house that has already dropped. What it does is take away one of the reasons it dropped. When the movement is minor, correcting the water may be the main recommendation; when piers are needed, drainage is still usually on the quote so the repair is not undone.
Should drainage be done before or after foundation repair?
Ask the specialist to explain their order. What matters most is that drainage is on the quote as its own line, with a scope you can see, rather than left out or folded into the structural price.
Does a raised house need drainage work too?
Often. Water that runs under a pier-and-beam house keeps the crawl space damp, which is what rots sills and joists and softens the soil under piers. Crawl-space moisture work and yard drainage are frequently quoted together.