Grading · French drains · Gutters & downspouts
Drainage correction for Central Texas foundations
Drainage correction treats the thing that actually moves most Central Texas foundations, water cycling the clay between soaked and bone dry. Grading, french drains, gutter and downspout corrections, and area drains, scoped from the same measured inspection as everything else we do. When your house needs a water fix that costs hundreds instead of a pier job that costs thousands, that's the quote you'll get. Want to handle the basics yourself first (gutters, grading, a soaker hose in drought)? What you can DIY and what you shouldn't draws the line, and if erosion has already left holes along the slab, how to fill holes around a house foundation covers the fix, cause first.
The toolbox
Four ways to move water away from the house.
Regrading
Soil rebuilt to slope away from the foundation, the fix for negative grade, settled backfill, and flower beds that hold water against the slab like a bathtub.
French drains
A gravel trench with perforated pipe that intercepts surface and subsurface water and carries it away before it reaches the foundation, the workhorse for chronic wet sides and uphill lots.
Gutters & downspouts
Extensions, splash management, and discharge relocation. A downspout dumping roof water at one corner is the single most common drainage failure we find on inspections.
Surface & area drains
Catch basins and channel drains where water ponds (patios, low spots, hardscape edges), piped to a discharge point that isn't beside your slab.
The mechanism
On expansive clay, water is usually the root cause.
Central Texas clay swells when it soaks and shrinks when it dries, and a foundation only suffers when that happens unevenly. Uncontrolled water is the great unevener: a downspout soaking one corner while the west wall bakes, a negative grade feeding every rain against the slab, runoff eroding the soil that supports a porch. Poor drainage damages slabs from both directions (heave where it's wet, settlement where erosion and the next drought take the support away).
That's why drainage correction isn't landscaping. It's foundation medicine. Piers treat the elevation; drainage treats the cause. Fix only the first and the clay keeps cycling around your repair; fix the water and the whole perimeter calms down. Under a pier and beam house the same water shows up as a damp crawl space and softened sills; crawl space moisture control is this same toolbox applied under the floor, and staying ahead of that water is the heart of routine pier and beam foundation maintenance. Heavy rain making cracks worse and drought damage are the same story from opposite seasons. Not sure which side of the line your house is on? Foundation repair or drainage correction walks exactly how the inspection makes the call.
Why it works
Why drainage protects your foundation.
The targets our crews grade and plumb to aren't guesses. They line up with the Foundation Performance Association's Drainage Guidelines, the engineering consensus on residential drainage. The ground next to the house should fall about six inches over the first ten feet so rain runs off instead of soaking in (the building code, IRC R401.3, uses that same minimum). Roof gutters are actually code-required on expansive soil (IRC R801.3), which describes most of San Antonio, and roof water should discharge at least five feet from the foundation, with a splash block carrying it eighteen inches or more past the slab edge. The Foundation Performance Association's Owner's Guide adds the other half: don't overwater the soil against the house, and seal the joints where flatwork meets the foundation so water can't run straight down beside the slab.
The point of every one of those numbers is to keep the clay around your house evenly moist instead of soaked in one strip and bone dry in another. That evenness is what keeps a foundation calm. Want the full how-and-why, with the grading, gutter, and slope details laid out? Our guide to foundation drainage in San Antonio is the deep dive. This page is where we come regrade the yard, correct the gutters, and put in the drains.
What we usually find
Sometimes you need drainage, not piers. We'll say so.
A meaningful share of the "foundation problems" we inspect turn out to be water problems wearing a structural costume (pooling at a corner, a soaked bed on a soaker hose, gutters overflowing at one wall). When the elevation survey says the slab is still within tolerance, the quote is the water fix, and it's often hundreds instead of thousands. If another company has already quoted you piers and your gut says the yard floods first, a free second opinion that includes the drainage walk is the cheapest insurance there is. Nobody here earns a commission on pier count. The readings decide, not a quota.
Drainage with pier work
When drainage pairs with pier work.
When a slab has already settled, drainage alone can't lift it. That takes piers and a measured lift. But piering a house while a downspout keeps soaking one corner is treating the symptom and feeding the disease, so combined scopes are common: piers where the readings demand support, drainage correction where the water was driving the movement, each priced as its own line item in the same written quote. The pier work carries our lifetime transferable warranty, and because that warranty doesn't cover damage caused by improper drainage around the home, getting the water right is also how you protect it. Good drainage is the cheapest maintenance a repaired foundation can get.
Measured scope
What the free inspection checks.
Grade & slope
Which way the soil actually falls at every wall. Negative grade against the slab is the quiet chronic offender.
Gutters & discharge points
Where every downspout dumps, whether gutters overflow at the corners, and which walls take roof water.
Ponding & erosion
Low spots that hold water after rain, and runoff paths that are carrying support soil away from slab and porch edges.
Irrigation & vegetation
Soaker hoses and sprinkler heads watering the foundation, and trees drinking one side dry, both halves of the uneven-moisture problem.
The elevation map
Floor elevations in tenths of an inch, so the drainage findings connect to what the slab has actually done, and the fix matches the facts.
From a Google review
“Drainage issues hurt my foundation, but Motmot Foundation Repair helped me fix my slab porch and pier and beam foundation and also installed a French Drain.”
Straight answers
Drainage questions, answered straight.
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