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Sakrete Home Additions & ADU: The San Antonio Owner’s Guide
If you’re planning a home addition or ADU and you’ve been researching Sakrete concrete and masonry products for the foundation, slab, or stem walls, here’s what you need to know: Mason Remodeling Co San Antonio installs Sakrete-mixed concrete on home additions and ADU projects throughout San Antonio, with full projects typically running $45,000–$130,000 for a home addition and $90,000–$220,000 for a detached ADU. We work with Sakrete bagged mixes on a wide range of foundation and flatwork applications, and we’ll verify the right mix, PSI rating, and pour conditions before a single yard is ordered. The most common reason a Sakrete-reliant project stalls isn’t the product itself—it’s a foundation pour that was spec’d wrong for San Antonio’s expansive clay soil, then cracked within the first two seasons.
Most homeowners discover the problem the way you probably did: you noticed a hairline crack running across the slab, or the new addition’s floor isn’t level after the first summer, or the ADU’s foundation developed a visible seam where two pours met. The concrete was Sakrete. The mix design was wrong for the application. Now you need someone who knows exactly which Sakrete product should have been used, and how to correct it without tearing the whole slab out.
We’re an independent San Antonio contractor—not affiliated with Sakrete—which means we can tell you plainly when a different Sakrete mix or a different pour method would have been the right call. Isaac Pruett has been pouring slabs and foundations across Texas long enough to read a crack and tell you what caused it before he ever puts a level on it.
Key takeaways:
- Installed home additions in San Antonio run $45,000–$130,000; ADUs run $90,000–$220,000.
- Foundation and slab work using Sakrete products is a sub-scope within those figures, typically $4,500–$12,000 for a slab depending on size and soil prep.
- The #1 cause of Sakrete foundation failures in San Antonio is using a mix with the wrong PSI for expansive clay soil.
- We give you a written price before any work starts—not a verbal estimate that grows on the final invoice.
Which Sakrete Products This Applies To
Sakrete makes dozens of bagged concrete and mortar products, and they are not interchangeable. The three we most often deal with on home addition and ADU projects in San Antonio are Sakrete High-Strength Concrete Mix (4,000 PSI), Sakrete 5000 Plus (5,000 PSI), and Sakrete Maximizer (up to 5,500 PSI with a coarser aggregate). Each has a specific place. The common compatibility gotcha: homeowners and some contractors use High-Strength 4,000 PSI mix for a load-bearing stem wall, when the structural plans called for something with more compressive strength. The mix cures, looks fine for a year, then hairline cracks appear at anchor bolt locations where tensile stress concentrates.
How to identify what was used in your existing slab: look for remaining bags in the garage or a materials invoice from the original contractor. If you don’t have that, a core sample and compression test run by a San Antonio testing lab will tell you the PSI and aggregate type. We can arrange that. For new work, we spec the Sakrete product by application: high-strength mix for non-load-bearing flatwork like patios and walkways, 5000 Plus for driveway-adjacent slabs and small addition foundations, Maximizer for stem walls and grade beams on ADUs. We also stock Sakrete concrete repair products for crack remediation: Top’n Bond, Flo-Coat, and latex-modified patching compound.
One thing to know about San Antonio specifically: the city sits on expansive clay that shrinks and swells dramatically with moisture. A 4,000 PSI mix that performs fine in Dallas or Austin may not be adequate for a foundation edge in the northeast side of San Antonio, where clay content runs higher. We account for that in the mix spec and the subgrade prep, not just the bag the plant puts in the mixer.
Styles & brands we work with
Signs Your Sakrete Home Addition or ADU Foundation Is Failing
- Hairline cracks that widen seasonally. The crack opens wider after heavy rain and tightens during dry spells. That’s expansive clay movement, and it means the slab isn’t reinforced or thickened enough at the edge. The concrete is doing what concrete does; the subgrade prep or the PSI spec was the problem.
- Doors and windows that stick only in the addition. When the original house is fine but the new addition’s doors bind, the addition’s slab is moving independently. In San Antonio, this usually means the addition slab wasn’t doweled into the existing foundation, or the Sakrete mix didn’t reach design strength before framing went up.
- A visible seam between two pours. If your ADU or addition slab was poured in sections and you can see the cold joint like a line across the floor, water is getting in and the two sections are moving separately. Cold joints are weak points, and on San Antonio clay they will separate further.
- Spalling or flaking on the slab surface. The top layer of concrete peels off in sheets. Spalling happens when water penetrates the surface, freezes (rare here, but possible in January), or when the mix had too much water added at the truck or the mixer. Sakrete products have strict water ratios printed on the bag—exceeding them cuts the cured strength significantly.
- Anchor bolts or sill plates that have cracked the concrete around them. You see a small crack radiating from every bolt along the bottom plate of the addition’s walls. The concrete wasn’t strong enough at the point of connection. On a San Antonio addition, this is nearly always a mix-strength issue, not a framing issue.
See the difference
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AfterReplacement Cost & What’s Included
For a full home addition in San Antonio, you’re looking at $45,000–$130,000 depending on square footage, whether it’s a bump-out or a full room, and the foundation method. A detached ADU runs $90,000–$220,000. When we’re talking specifically about Sakrete-related foundation repair or replacement within that scope, foundation work on a small addition typically lands in the $4,500–$12,000 range, and that includes removal of the failed slab section, subgrade correction, rebar or mesh, the correct Sakrete mix at proper PSI, and finish work.
That price is written down before we start. It includes material, labor, haul-off, and the specific Sakrete product we’re using, listed on the line item. Not “concrete”—the actual name on the bag. If we find something unexpected when we open up the slab, we stop, show you what we found, and give you a written change before touching anything else. No surprises on the final bill. The work is covered by our 365-Day Done Right Promise: if something isn’t right within a year of completion, we come back and make it right at no cost to you, no dispute process.
DIY or Call Us?
What you can safely do yourself: mark the crack locations with painter’s tape and dates, photograph them, and track whether they widen after rain. That gives us useful diagnostic information. You can also confirm which Sakrete product was originally used by checking leftover bags or invoices. What we’d stop you from doing: don’t fill foundation cracks with retail caulk or patching compound and call it fixed. A crack is a symptom. If the underlying mix strength or subgrade prep is wrong, sealing the surface just hides the problem while water continues to work underneath. And don’t attempt a slab-section replacement yourself—the removal alone involves saw cutting, rebar tying, and heavy material handling that goes wrong fast without the right equipment.
If what you’re seeing matches any of the symptoms above, call (254) 269-5071. Isaac and the crew will come look, tell you what’s actually happening, and give you a written price for the fix—no obligation, no pressure. Know who’s coming, know what it costs, know it’s covered—that’s the whole job before the job starts.
FAQs
A properly spec’d and properly poured Sakrete slab on a San Antonio addition should last 30–50 years with minor maintenance, but the first 24 months after the pour are the critical window—that’s when mix-strength and subgrade problems reveal themselves. If you’re seeing cracks before year two, the fix is usually partial slab replacement or subgrade correction, not surface patching. Call (254) 269-5071 for an inspection and a written price.
Yes, in most cases—if the crack is hairline and not moving, we can often stabilize with epoxy injection or a Sakrete repair product and monitor it; if the crack is widening or doors are binding, the underlying slab section likely needs removal and re-pour with the correct mix. The answer depends on what’s actually under the crack, which we determine with a site inspection. Estimates are free—call (254) 269-5071.
Most Sakrete slab-section replacements on San Antonio additions take 3–5 days from demo to cured concrete, with the pour typically happening on day 2 or 3 and curing time built in before we put any weight on it. We’ll give you a day-by-day schedule in writing before we start, so you know exactly when the crew will be there and what they’ll be doing. Call (254) 269-5071 for a written schedule and price.
Yes—our San Antonio crews stock Sakrete High-Strength Concrete Mix, 5000 Plus, Maximizer, and a range of Sakrete repair products on the truck for most jobs, so we’re not running back and forth to the supply yard mid-project. If your project calls for a specialty Sakrete mix we don’t stock, we order it and it’s on site before the pour date. Call (254) 269-5071 and we’ll confirm what your job needs.
No—the written price we give you before work starts is the price you pay, unless you ask us to add scope or we uncover something hidden and get your written approval first. We’ve operated that way in San Antonio since 2004, and we’ve never sent a client a surprise invoice. Call (254) 269-5071 to get your written estimate started.
We also work with KraftMaid cabinetry, Cambria and Silestone countertops on the interior finishes of the additions and ADUs we build—if you’re planning the whole project, we can spec those materials alongside the Sakrete foundation work, all on one written price.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
