The straight answer first. A standard broom-finish concrete patio in St. Charles County runs $10–$15 per square foot installed in 2026. A stamped concrete patio runs $16–$25 per square foot. Decorative work — integral color, acid stain, exposed aggregate — runs $18–$30 per square foot depending on the finish.
Those are real ranges from current True Form Concrete jobs in St. Charles, O'Fallon, St. Peters, and the surrounding suburbs. Every other concrete contractor in the county will quote you "it depends" and book a site visit before sharing a number. That's fair — every project genuinely is different — but you deserve a starting frame of reference before the phone call.
This guide walks through what those numbers actually buy you, what changes the price, and where cheap quotes hide their savings.
What changes the price
Five variables move the per-square-foot number more than anything else:
- Slab thickness. Standard residential patios are 4 inches thick. Pool decks, outdoor kitchens, and hot-tub pads jump to 5 or 6 inches. Each inch is roughly 10–15% more material and labor.
- Sub-base preparation. A 4-inch compacted clean-stone base is standard. Skipping it (or using only 2 inches) saves the contractor a couple hundred dollars and costs you a patio in five years.
- Reinforcement. Fiber mesh is included on most quotes. Rebar adds $1–$2 per square foot but is non-negotiable for any patio over 400 sq ft or any slab supporting heavy loads.
- Access. Can the concrete truck back up to the pour site, or do we wheelbarrow it 80 feet around the side of the house? Access alone can swing a quote by $1.50–$3 per square foot.
- Finish. Broom is the baseline. Stamping adds patterns, color hardener, release powder, and an extra day of labor. Decorative finishes add still more.
How clay soil quietly drives up the cost
St. Charles County sits on expansive clay. That soil moves 1–3 inches with seasonal moisture swings, and it heaves harder than most homeowners realize. A patio built on poorly-prepped clay subgrade will crack inside two winters.
The fix is a deeper compacted stone base — sometimes 6 inches instead of 4, sometimes with a geotextile fabric layer between subgrade and stone. That's another $1–$2 per square foot, and a contractor who isn't quoting it for your lot is either inexperienced or banking on you not knowing the difference. We cover this in detail in our grading and site prep page.
Stamped vs broom vs exposed aggregate — what each finish actually costs
| Finish | 2026 Range | Why It's That Price |
|---|---|---|
| Broom finish | $10–$15/sq ft | Standard slab, single-color, no decorative work. The "default." |
| Salt finish | $11–$16/sq ft | Broom base with rock salt pressed in and washed out for texture. |
| Exposed aggregate | $14–$20/sq ft | Decorative stone aggregate revealed by surface washout. High-end finish. |
| Stamped, single-color | $16–$22/sq ft | Stamping mats + color hardener + release agent + extra labor day. |
| Stamped, two-color w/ release | $20–$28/sq ft | Antique-look layered color, much more visual depth. |
| Decorative + acid stain | $22–$32/sq ft | Custom-mixed translucent color, hand-applied after cure. |
The biggest mistake homeowners make is comparing a $11/sq ft quote against a $19/sq ft quote and picking the lower one. They're not the same product. We break this down further in our stamped concrete pricing guide.
Real budgets — three example projects
Example 1: 200 sq ft back patio, broom finish, St. Peters
Small rectangular patio off the back door, easy truck access, standard 4" slab on prepped sub-base. Single broom finish, no stamping. Total: $2,400–$3,000. Typical turnaround is 4–5 days from estimate to cure-ready.
Example 2: 400 sq ft stamped patio, O'Fallon
Wraparound patio with a stamped ashlar slate pattern, two-color release, sub-base appropriate for clay soil, control joints cut to break up the panel. Total: $8,000–$10,400. About 7 days estimate to cure-ready.
Example 3: 600 sq ft wraparound with outdoor kitchen pad, Lake St. Louis
Large wraparound with stamped main area, separate 8x10 thickened slab for an outdoor kitchen island, pre-pour gas and electric sleeves, drainage slope to lakeside, custom border pattern. Total: $14,400–$18,000. Roughly 10–14 days due to phased pours.
Financing options and what monthly payments look like
We work with a couple of financing partners that handle home-improvement loans for projects in the $5K–$50K range. Typical structures:
- 0% promo for 12 months on projects over $5K — best for homeowners planning to pay off within the year.
- 5–7-year fixed rate at competitive APRs — best for stretching a larger project (outdoor kitchen, pool deck, wraparound combo) over time.
An $8,000 stamped patio on a 5-year fixed loan runs roughly $150–$175 per month. We do the application process during your free estimate visit and you'll know your approval and payment range within 24 hours.
Red flags in a low bid
If a competing quote comes in 25%+ below ours, the line items below are usually missing:
- Sub-base depth not specified. A real quote says "4-inch compacted CA-6 stone base." A bad quote says "prep base."
- PSI not called out. 4,000 PSI is the Missouri minimum for residential patios. If it's not in writing, you may get 3,000.
- No fiber or rebar listed. Unreinforced concrete cracks faster.
- No control joint plan. Joints aren't decorative — they prevent random cracking. They should be tooled or saw-cut to a specific spacing based on slab size.
- Haul-off not included. Tear-out fees for an existing patio can run $1–$3 per square foot; if it's not listed, you'll get a "surprise" line item later.
- Warranty language vague or absent. A real workmanship warranty is in writing and covers 1–2 years on cracks beyond control joints.
Where True Form fits in this price range
Our quotes land in the middle of the ranges above for the standard finishes and toward the upper end for stamped and decorative — because we pour 4,000 PSI minimum, run a proper compacted stone base, use fiber mesh as standard with rebar on every patio over 400 sq ft, and do every pour with our own in-house crew. No subcontracted labor, no shortcuts on sub-base, no "we'll figure out drainage as we go."
If you want a real number for your specific project — your slope, your soil, your access, your finish preference — we'll come out free and quote it within 48 hours. Most quotes are scheduled within a week of your call.
Get a real number for your project
Every project is different — slope, soil, access, finish. We do free on-site estimates within 48 hours of your call.