Dirt delivery in San Antonio
San Antonio straddles a soil line: expansive Blackland clay south and east, limestone and caliche north up the Balcones Escarpment. A slab on the clay wants select fill in 6 to 8 inch lifts, a Hill Country lot wants imported topsoil and gravel. Gravel is available here.
Which material do I need in San Antonio?
In San Antonio the answer depends which side of the escarpment you are on. South and east on the Blackland clay, a pad gets built out of select fill in 6 to 8 inch compacted lifts, because the native clay swells and shrinks too much to build on. North toward Boerne, on limestone and caliche with almost no soil, the orders flip to imported topsoil for anything that grows and gravel for driveways and pads. Clay fill covers bulk volume across both.
What is the ground under San Antonio made of?
San Antonio straddles a geological line. South and east of the city, out toward Seguin and the coastal plain, the ground is Blackland Prairie clay: dark, deep and expansive, the same shrink and swell problem that defines building across much of Central Texas. Slabs on that ground move with the seasons unless they sit on an imported pad.
North and west, up the Balcones Escarpment toward Boerne and the Hill Country, the geology flips to Edwards limestone with a caliche cap and thin rocky soil over rock close to the surface. Excavation gets harder, the ground heaves less, and the material question changes from how to build on clay to how to get workable soil onto a rocky lot. This is also the Edwards recharge zone, which is why drainage and what goes on the ground carry extra scrutiny here.
What do people buy dirt for here?
On the Blackland clay through the southern and eastern suburbs, a residential or commercial pad gets built out of select fill in 6 to 8 inch compacted lifts rather than by reworking the native ground. It is the same method that governs Austin and Dallas and it is the biggest single use of bulk fill in this half of the metro.
North of the escarpment, toward Boerne and Helotes, a new lot is often rock and caliche with almost no soil to grow anything. Imported topsoil for beds and lawns and gravel for driveways and pads are the common orders where the native ground will not do either job on its own.
A gravel driveway is a normal finish on acreage around New Braunfels and Seguin, and a compacted base under a concrete drive is standard on the clay. Both are material we deliver by the cubic yard, and the right product depends on whether the drive is the finished surface or a base for concrete on top.
A decommissioned pool gets its shell broken for drainage and backfilled with common fill, and it takes more yardage than owners expect. Regrading a lot to fall away from a slab on the expansive south-side clay is one of the cheapest things a homeowner here can do for a foundation.
What do the local material names mean?
San Antonio's material vocabulary spans two grounds, the Central Texas clay terms and the Hill Country rock and gravel terms, and the right word depends on your address.
The compactable, spec-driven fill used to build pads over the Blackland clay in the southern and eastern suburbs. Plans name a plasticity index ceiling and a compaction percentage. It is the defining structural material on the clay side of the metro.
The natural cemented calcium-carbonate hardpan common north of the escarpment. Locally it is also sold as a cheap base and drive material because it packs hard, though it turns greasy when wet. If your lot is caliche, expect excavation to be closer to a rock job than a dirt job.
Crushed rock delivered by the cubic yard, used as a driveway surface on acreage and as a compacted base under concrete drives and slabs. The right product depends on whether the gravel is the finished surface or a base for something poured on top. Gravel is available in this market.
The bulk mineral subsoil bought for volume: raising a low yard, backfilling a pool, levelling a lot. It runs clay-heavy on the south and east side and thinner and rockier toward the Hill Country.
Imported growing soil, in heavy demand north of the escarpment where the native ground is rock and caliche with almost nothing that grows. 4 to 6 inches over graded ground is what establishes a lawn on a Hill Country lot.
How does the Edwards recharge zone affect a job?
Building over the northern part of San Antonio means building over the Edwards Aquifer recharge zone, the porous limestone where surface water enters the aquifer that supplies the region. Development there carries extra scrutiny on drainage, erosion and what goes on the ground, and on regulated sites there is a water quality plan behind the grading. That is a matter for whoever designs the site, but it is worth knowing it is why a northern lot has rules a southern one does not.
On the clay side, the governing fact is the shrink and swell of the Blackland ground. A slab wants an imported select fill pad compacted in lifts to a specified density, and on an engineered job the compaction specification rather than the material price is what decides whether the pad passes. Send us the geotechnical report if you have one and we will tell you whether we can source to it.
Across the whole metro, access is the third input. Steep caliche driveways and narrow ranch-road frontage in the north can keep an 18-wheeler out, which means more trips in smaller dump trucks and a different price per cubic yard. Describe the approach when you order.
How does scheduling and access work here?
San Antonio is a wide metro with two different grounds in it, so haul distance and which side of the escarpment your address sits on both matter to a quote. Standard orders run 1 to 3 days from stock. Very large orders of around 500 loads or more can be sourced to the cheapest supply instead. Gravel is available in this market alongside the three soil materials.
The Hill Country access problem is real. Steep caliche driveways, narrow ranch-road frontage and rock ledges can stop an 18-wheeler, which means more trips in smaller dump trucks and a different price per cubic yard. Tell us about the approach when you order rather than when the driver is on the street.
How many yards will my San Antonio job take?
A pad on the clay side is the volume job. A 40 foot by 50 foot pad raised 12 inches is about 74 cubic yards in place, or 89 to 93 ordered once a compaction allowance for lifts is applied. Ordering the in-place figure is the usual reason a pad runs short on the last lift.
A Hill Country lot runs differently. Topsoil for a 4,000 square foot lawn at 4 inches is about 49 cubic yards, and a gravel driveway is priced off length, width and depth like any other material, plus a compaction allowance. Give us the dimensions and we will run it with you.
Which cities do we deliver to?
- San Antonio
- New Braunfels
- Schertz
- Converse
- Boerne
- Helotes
- Universal City
- Cibolo
- Seguin
Those are the San Antonio-area cities we list. The northern and eastern suburbs around them are generally reachable. Coverage is a haul distance question, so give us the address and we will answer it straight.
San Antonio dirt delivery questions
What dirt do I need for a slab in San Antonio?
On the Blackland clay south and east of the city, select fill placed in 6 to 8 inch compacted lifts to your engineer's specification. Building the pad out of imported material rather than reworking the expansive native clay is standard, because that clay moves with its moisture.
Do you deliver gravel in San Antonio?
Yes. Gravel is available in this market alongside fill dirt, select fill and topsoil, delivered by the cubic yard. Whether you want a driving surface or a compacted base under concrete changes the product, so tell us what it is for when you order.
What is caliche and is it good to build on?
Caliche is a natural cemented hardpan common north of the escarpment. It packs hard and is sold cheaply as a base and drive material, but it turns greasy when wet and drains poorly, so under a slab an engineered select fill pad is the safer answer.
Why does my north-side lot have more rules?
Much of the northern metro sits over the Edwards Aquifer recharge zone, where surface water enters the aquifer. Development there carries extra drainage, erosion and water quality scrutiny. It is handled by the site designer, but it is why a northern lot has requirements a southern one does not.
How soon can you deliver in San Antonio?
Most orders run 1 to 3 days from stock. On very large orders of around 500 loads or more we can source to the cheapest supply instead. On the clay side rain moves dates, because saturated clay cannot be placed or compacted, and Hill Country access can decide the truck size.
Need dirt in San Antonio?
Tell us the address, the cubic yards and the date you need it by. If your address is not on the list above, ask anyway. Coverage is about haul distance.