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Quikrete Home Additions & ADU: The San Francisco Owner’s Guide
Home additions and ADU construction in San Francisco typically run $53,100 to $153,400, depending on square footage, foundation work, and whether you’re building up or out on your lot. We handle the full Quikrete scope: foundation forms, slab pours, stem walls, and the structural concrete that carries your new square footage. Most homeowners contact us after they’ve spotted a crack in an existing foundation or realized their old concrete wasn’t mixed or cured to spec for San Francisco’s soil conditions.
Quikrete products hold up differently in San Francisco than they do inland. Our fog, salt air, and clay-heavy soils in districts like the Outer Sunset and Excelsior put real stress on concrete work. A pour that would last decades in Sacramento can show spalling or efflorescence within a few years here if the mix wasn’t right or the ground wasn’t prepped properly. That’s the conversation we have most often: the product isn’t the problem. The prep and the pour schedule usually are.
We’re an independent contractor in San Francisco, not affiliated with Quikrete. We stock their bagged mixes and use their specified products on additions and ADUs because the specs are consistent and the material is traceable. That matters when a building inspector wants to see exactly what went into your foundation.
Which Quikrete Models This Applies To
The Quikrete products relevant to home additions and ADUs in San Francisco fall into a few distinct lines. You’re not matching a part number the way you would with a faucet cartridge. You’re matching the right mix to the right application, and the wrong choice is expensive to fix after the pour.
The bags you need to know:
- Quikrete 5000 Concrete Mix – the standard for load-bearing footings, stem walls, and slabs in San Francisco. Rated at 5,000 PSI after 28 days. If your structural drawings call for anything less on a foundation, that’s a red flag.
- Quikrete ProFinish Crack Resistant Concrete Mix – reinforced with polymer fibers. We specify this on ADU floor slabs in San Francisco because it handles the minor ground movement our clay soils produce between wet and dry seasons.
- Quikrete Concrete Mix (1101) – the basic 4,000 PSI mix. Fine for non-structural applications like walkways or small patio pads. Not what we’d pour for an addition that carries roof and wall load.
- Quikrete FastSet Concrete Mix – good for setting fence posts or small repair pads. Do not use FastSet on structural work. It kicks before you can properly vibrate and finish a slab.
The compatibility gotcha most San Francisco homeowners hit: your structural engineer’s drawings specify a PSI rating, not a bag brand. If your plans call for 4,000 PSI concrete with a 4-inch slump and #4 rebar on 16-inch centers, the Quikrete mix you choose has to meet or exceed that spec. We’ve walked onto San Francisco job sites where a previous contractor poured the wrong PSI mix into a footing and the inspector made them tear it out. That’s a five-figure mistake. We pull the bag tags and keep them with the permit paperwork so the inspector can verify every pour.
Styles & brands we work with
Signs Your Quikrete Home Additions & ADU Is Failing
Concrete doesn’t fail quietly. It gives you signals early, and catching them in San Francisco before winter rain saturates the subgrade saves real money. Here’s what we see on existing foundations and slabs across the city:
- Hairline cracks that widen in winter. San Francisco’s clay soil expands when wet and contracts when dry. A crack that opens and closes with the seasons usually means the footing wasn’t dug deep enough or the base rock wasn’t compacted properly.
- White powdery deposits on the surface (efflorescence). Water is moving through the slab and depositing salts. In San Francisco’s damp climate, this almost always traces back to a missing or failed vapor barrier under the pour.
- Spalling or flaking at the edges. Surface concrete breaking away in chunks means the mix was too wet when poured, or the top was over-finished and trapped water inside. Salt air near Ocean Beach and the Sunset accelerates this.
- Standing water that doesn’t drain off the slab. Your slab has settled or was poured without proper slope. On an addition, that water works its way under the building and starts a rot cycle in the sill plate.
- Doors and windows sticking after years of opening fine. The slab or the footing under a wall has moved. In San Francisco, this is common on hillside lots in neighborhoods like Noe Valley or Glen Park where the original foundation wasn’t pinned to stable soil.
See the difference
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After
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After
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AfterReplacement Cost & What’s Included
Full home addition work in San Francisco runs $53,100 to $153,400. ADU construction starts higher, at $106,200 and runs to $259,600, because you’re dealing with separate utility connections, fire-rated assemblies, and San Francisco’s accessory dwelling unit review process. A garage conversion typically lands between $35,400 and $94,400 depending on whether the existing slab is usable or has to be cut out and re-poured.
What drives the spread inside those ranges:
- Foundation complexity. A flat, compacted lot in the Outer Sunset is a different job than a hillside in Bernal Heights that needs piers or a retaining wall first.
- Square footage. More slab means more material, more rebar, more finishing labor. The material math doesn’t flex much; it’s mostly labor and time on-site.
- Access. San Francisco lots are tight. If we can’t get a concrete truck to the pour site, we’re running mixers manually or pumping, and that labor cost shows up in the number.
- Existing slab condition. If the old concrete is cracked through and needs full removal and re-pour, that’s additional cost beyond the new work.
Every bid from Bradford Remodeling Co San Francisco includes a written price before work starts. No numbers that move at the door. When we finish, you get a signed copy of our 365-Day Done Right Promise: if the concrete work fails within one year, we come back and correct it at no charge. That’s The Garrison Standard we’ve operated under since 2004.
DIY or Call Us?
Mixing and pouring structural concrete is not a weekend project. Get it wrong and you’re not re-tiling a backsplash; you’re tearing out a slab that’s carrying your house. When concrete fails, it fails big. The danger here is structural, not something that’s going to crimp your finger. A footing that’s poured too dry, too wet, or without proper reinforcement can settle and crack under load, and that puts the entire addition or ADU at risk.
What you can safely do yourself: keep an eye on existing slabs, document cracks with photos and dates, and check drainage after rain. What you should not do: pour a structural footing from bags mixed in a wheelbarrow. Bagged Quikrete works when the water ratio is exact, the mixing time is consistent, and the pour is placed and finished in one continuous operation. That’s crew work with the right tools and the right inspection schedule.
If you’re seeing failure signs in an existing slab or planning an addition in San Francisco, call (831) 610-5598. We’ll send Curtis Lane or one of our project leads out to look, and you’ll get a straight number on what it costs to fix.
FAQs
A properly poured and maintained reinforced concrete slab in San Francisco should last 50 to 80 years, but that assumes the base was compacted, the vapor barrier was installed, and the mix hit its specified PSI. We’ve torn out slabs that failed in 10 years because the ground under them was never prepared. Call (831) 610-5598 if you’re seeing cracks widen and want an honest read on whether it’s repairable or a tear-out.
Hairline cracks under a quarter-inch wide can often be sealed and monitored. Cracks wider than that, or cracks that show vertical displacement from one side to the other, usually signal a foundation problem that patching won’t fix. The answer depends on what’s happening under the slab, not on the surface. We’ll tell you which one you’re dealing with for free.
The pour itself is usually a single day. The concrete reaches about 70% of its rated strength after 7 days and full strength at 28 days. We keep the site covered and damp-cure in San Francisco’s dry summer months to prevent the surface from drying too fast and cracking. Framing typically starts about a week after the pour.
We bring the Quikrete material to the site. We order full pallets from our San Francisco suppliers and verify the mix spec against your structural drawings before any bag gets opened. You’ll see the bag tags in the permit file. If you’re also planning cabinetry or counters for the finished space, we work with KraftMaid, Cambria, and Silestone as well, so one crew handles the whole job from slab to close-out.
Straight number, real scope, no surprises at close-out. That’s how we run every addition and ADU in San Francisco. Call (831) 610-5598 to schedule your free estimate.
Written by Curtis Lane, Owner, Bradford Remodeling Co – San Francisco, CA at Bradford Remodeling Co San Francisco, serving San Francisco and nearby areas.
