Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Quikrete Home Additions & ADU: The San Antonio Owner’s Guide
If you’re planning a home addition or ADU in San Antonio and want Quikrete products used in the foundation, slab, or masonry work, a full project typically runs $45,000 to $130,000 for a home addition and $90,000 to $220,000 for a detached ADU. That range includes the concrete work, framing, finishes, and the written price before a single tool leaves the truck. Most owners reach out after they’ve already priced the Quikrete bags at a big-box store and realized the difference between buying product and getting a slab poured, cured, and finished correctly under Texas sun.
What we see most often in San Antonio: a homeowner starts a backyard ADU or a room addition, the foundation gets poured with Quikrete mix, and then cracks appear within the first year because the soil shifted or the mix wasn’t right for our clay-heavy ground. Or they bought the bags planning to do the slab themselves and hit the reality of rebar spacing, expansion joints, and a 100-degree pour day. Either way, we’re the crew that steps in, matches the Quikrete product to the job, and writes every step down before work begins.
Which Quikrete Models This Applies To
Quikrete isn’t a single product line, and the version you need depends entirely on what part of the addition or ADU you’re building. For San Antonio slabs and footings, the relevant products are Quikrete 5000 (rated at 5,000 psi, our default for ADU foundations because it handles the expansive clay soil better than standard 4,000 psi mixes), Quikrete Crack-Resistant Concrete Mix for interior slabs where you’re worried about early hairline cracking, and Quikrete Mason Mix or Type S Mortar for stem walls and block work.
The compatibility gotcha most homeowners miss: Quikrete 5000 sets faster than Quikrete’s standard Concrete Mix, which matters when temperatures hit 95-plus degrees in July. You have less working time before the mix stiffens, and if the crew isn’t accounting for that, you’ll get cold joints and weak spots in the slab. We also stock Quikrete’s fast-setting and high-strength mixes on the truck for specific phases, and we’ll tell you honestly whether an aftermarket equivalent (usually a local ready-mix supplier’s 5,000 psi mix) will outperform bagged Quikrete for a slab larger than about 150 square feet. For footings under frost depth (which isn’t a factor in San Antonio, but is in the Hill Country just north of us), bagged product holds up fine.
Styles & brands we work with
Signs Your Quikrete Home Additions & ADU Is Failing
- Hairline cracks running across the slab within the first 6 months. This usually means the mix was too wet when poured, or the slab cured too fast in San Antonio’s dry heat. Adding too much water to Quikrete mix is the single most common DIY mistake we see.
- Cracks wider than a quarter-inch with one side higher than the other. That’s differential settlement, and in San Antonio it nearly always traces back to expansive clay soil that wasn’t prepared correctly before the pour. The Quikrete product itself is rarely the problem; the sub-base is.
- Pitting or surface flaking (spalling) on the slab surface. This shows up within the first year on adds and ADUs where the Quikrete was over-troweled or the surface dried too quickly in direct sun without proper curing. San Antonio’s 100-degree afternoons will do this to a well-mixed slab if nobody kept it damp during the first week.
- Cracks radiating from corners of doors or windows in the addition. In a wood-framed addition sitting on a Quikrete slab, corner cracks often point to missing or undersized rebar, not a product failure. The slab is flexing where the frame loads it.
- Water pooling on the slab after rain instead of running off. This is a slope and finishing issue at the time of pour. Quikrete mix can be screeded to any fall, so if water’s ponding, the finished grade was wrong from the start.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
For a home addition in San Antonio, you’re looking at $45,000 to $130,000, and a detached ADU runs $90,000 to $220,000. That’s the full project cost, not just the Quikrete work. If all you need is a failed slab torn out and repoured, a smaller ADU slab or addition floor slab generally falls in the $8,000 to $25,000 range depending on square footage, access for equipment, and whether we’re hauling out the old concrete or pouring over a properly prepared base.
Every quote includes the Quikrete product specified by name and psi rating, the rebar schedule, sub-base prep, expansion joint placement, finishing, and the curing plan. You’ll get a written price before any work starts, and it stays the same unless you change the scope in writing. The labor warranty on our concrete and masonry work is covered under the 365-Day Done Right Promise: if it’s not done right after the job is complete, we make it right. For an existing addition or ADU with foundation problems, we’ll bring in a structural engineer when the cracking pattern suggests settling rather than a surface issue, and that report is yours to keep.
DIY or Call Us?
You can safely check a few things yourself before calling: measure the crack widths with a quarter, note whether one side is higher, and check if the slab surface flakes when you drag a screwdriver across it. That tells us a lot before we even show up. What you shouldn’t do is start chipping out and repouring sections of a load-bearing slab on an occupied addition or ADU. If you remove the wrong section or pour a patch that doesn’t bond, you can compromise the structure you’re living in.
Quikrete bagged concrete is a good product, but slab work is not a weekend project when it’s under a home addition. The rebar layout, soil prep, and curing schedule are where additions in San Antonio live or die. If you’d rather hand that off to a crew that will write the full scope down before starting, call (432) 233-0976. We’ll come out, look at the slab, and give you a written price for exactly what needs to happen.
FAQs
A properly mixed, poured, and cured Quikrete 5000 slab in San Antonio should last 50-plus years. The failures we see before that are almost always prep, water-ratio, or curing problems, not the product itself. Our written scope includes the curing steps because Texas heat is the real enemy. Call (432) 233-0976 if you want us to look at what’s cracking and tell you whether it’s structural or cosmetic.
Yes, if the crack is stable and the slab isn’t settling, we can often repair it with epoxy injection or a resurfacing product and seal the joint. If the slab is still moving because of expansive soil, a repair will fail the same way the original did. We’ll tell you which situation you’re in before recommending any work, and the written price you get is the price you pay.
A home addition typically takes 4 to 7 months from permitting through final walkthrough, and a detached ADU runs 6 to 10 months depending on utility runs and foundation scope. Concrete curing alone needs 7 days of moist curing before we frame on top, and we’ll put that timeline in writing before we start. Call (432) 233-0976 and we’ll walk you through a realistic schedule for your specific lot.
We stock Quikrete 5000, Crack-Resistant Concrete Mix, and Mason Mix on the truck for small pours, repairs, and stem wall work. For full slabs, we’ll often order from a local batch plant because the mix is more consistent and the cost is better, and we’ll put that product name and psi rating in your written quote. We also work with brands like KraftMaid, Cambria, and Silestone for the finishes that follow the concrete, so the whole project is specified by name before work begins.
Write it down, price it once, do it right. That’s how Graham Stein runs every Elmstead Remodeling San Antonio job, and it’s how your addition or ADU gets from a Quikrete bag to a finished room. Call (432) 233-0976 for a free estimate, and we’ll put the numbers in writing before any work starts.
Written by Graham Stein, Owner, Elmstead Remodeling San Antonio at Elmstead Remodeling San Antonio, serving San Antonio and nearby areas.
