
If you’re dealing with basement moisture, foundation cracks, or sunken concrete in your St. Charles County home, Cornerstone Structural Repair & Waterproofing is here to help. As a trusted foundation repair contractor in St. Charles County, MO, we specialize in long-term solutions that protect your home’s structure, restore value, and give you peace of mind. Our services include foundation crack repair, basement waterproofing, egress window installation, and concrete repair and leveling, all tailored to meet the unique needs of homes in the greater St. Louis area.
With decades of combined experience and a reputation for honest service, Cornerstone proudly serves homeowners in St. Charles, O’Fallon, Wentzville, St. Peters, and surrounding communities. Contact us to learn more or request a foundation and basement waterproofing quote today.
Local Expertise for St. Charles County Homes
St. Charles County has seen substantial growth in recent decades, combining older homes with a surge of newer residential developments. From historic homes near Main Street St. Charles to suburban neighborhoods in Dardenne Prairie and Lake St. Louis, each home comes with its own set of structural challenges.
Common Issues in St. Charles County Homes:
- Foundation cracks due to shifting soil and seasonal changes
- Water seepage and flooding in basements during heavy rain
- Settled or uneven concrete in driveways and walkways
- Outdated or non-code basement windows
These issues are often caused by the region’s expansive clay soil, poor drainage, or inadequate waterproofing during original construction. At Cornerstone, we understand the construction practices and soil conditions in St. Charles County, and we tailor our repair solutions accordingly.
Cities We Serve in St. Charles County:
- St. Charles
- O’Fallon
- St. Peters
- Wentzville
- Lake St. Louis
- Dardenne Prairie
- Cottleville
- Weldon Spring
- Augusta
Whether you’re in a century-old farmhouse or a newer build with foundation settling, we’re here to help.
Our Foundation and Waterproofing Services
At Cornerstone Structural Repair & Waterproofing, we don’t offer one-size-fits-all solutions. Instead, we take the time to evaluate your home, identify the root cause of your concerns, and develop a custom plan that fits your home and your budget.
Foundation Crack Repair
Foundation cracks can result from soil pressure, water saturation, or natural settling. Our team uses high-quality polyurethane or epoxy injections and other structural repair methods to stop the problem at its source and prevent further damage.
Basement Waterproofing
A dry basement is essential for home health and value. We install proven waterproofing systems that address moisture before it becomes a serious issue. Our solutions include:
- Interior French drains
- Sump pump installation and battery backup systems
- Vapor barriers and wall sealing
- Exterior grading and drainage improvements
Whether you’re already seeing signs of water damage or want to prevent future issues, we’ll design a custom waterproofing system to keep your basement dry year-round.
Egress Window Installation
If you’re remodeling or finishing a basement, installing a code-compliant egress window is essential. Not only does it improve safety and meet local building codes, it also allows for more natural light and ventilation. We handle the complete process, from excavation and drainage to installation and finishing, so your new space is beautiful and functional.
Concrete Repair and Leveling
Uneven concrete poses both safety hazards and aesthetic concerns. Using polyurethane foam injection, we lift and stabilize concrete slabs with minimal disruption. This service is ideal for driveways, sidewalks, garage floors, and patios, and can often be completed in a single day.
Why Choose Our Foundation Repair Contractor in St. Charles County?
- Deep Local Knowledge: We know the soils, weather patterns, and housing styles in St. Charles County because we work here every day. This allows us to provide more accurate assessments and better long-term results.
- Transparent Service: We believe in doing the right thing for every customer. That means honest inspections, no high-pressure sales, and clear communication throughout your project.
- Skilled Workmanship: With decades of experience and a commitment to using proven repair methods, we deliver top-tier results backed by warranties on many of our services.
- Personalized Solutions: No two homes are alike. That’s why we tailor every repair plan to meet the specific structural and environmental needs of your home.

Frequently Asked Questions for Our Foundation Repair Contractors
What are signs that I may need foundation repair?
Watch for stair-step or horizontal cracks in walls, doors or windows that stick, uneven floors, or water entering the basement. Any of these symptoms may indicate foundation movement.
Learn more about signs of foundation problems.
Is water in my basement a serious issue?
Yes. Moisture can lead to mold growth, wood rot, structural damage, and poor indoor air quality. Waterproofing is a wise investment that protects both your home and health.
Can you repair concrete without replacing it?
Yes. Our polyurethane foam leveling process allows us to lift and stabilize existing slabs without costly and time-consuming demolition.
How long does an egress window installation take?
Most installations are completed in 1 to 2 days, including excavation, drainage, window placement, and finishing. We handle every step of the process.
Learn more about the egress window installation process.
Do you serve rural and suburban areas?
Absolutely. Whether you’re in the heart of St. Charles or in a more rural setting like Augusta or Weldon Spring, our team is ready to help.
Contact Our St. Charles Foundation Repair Contractor to Schedule Your Free Estimate Today
If you’re searching for a reliable foundation repair contractor in St. Charles County, MO, look no further than Cornerstone Structural Repair & Waterproofing. From foundation crack repair and basement waterproofing to egress windows and concrete leveling, we offer expert solutions that protect your home and restore your peace of mind.
Call us today or contact us online to schedule your free inspection. We’ll assess your concerns, explain your options, and develop a custom plan that works for your home and your budget. Cornerstone is your trusted local expert in structural stability and moisture protection.

