Polyurethane concrete raising—also known as foam jacking or polyjacking—has become a go-to solution for fixing sunken or uneven concrete. Whether it’s your driveway, sidewalk, garage floor, or patio, lifting concrete with polyurethane foam is a fast, effective, and long-lasting alternative to replacing the entire slab. But if you’re new to this process, you probably have questions. That’s why we’ve compiled this comprehensive FAQ guide to help you understand everything about polyurethane concrete raising.
1. What is Polyurethane Concrete Raising?
Polyurethane concrete raising is a technique used to lift and level sunken concrete by injecting high-density polyurethane foam underneath the slab. The foam expands and hardens, filling voids and gently raising the slab back to its original position.
2. How Does Polyurethane Foam Lifting Work?
The process involves:
- Drilling small holes (5/8 inch) into the affected concrete
- Inserting injection ports
- Pumping polyurethane foam beneath the slab
- Allowing the foam to expand and lift the concrete
- Patching the holes once the slab is level
The entire procedure is typically quick and minimally invasive.
3. What Are the Benefits of Using Polyurethane Foam?
Some key advantages include:
- Quick cure time (can be used in minutes)
- Minimal disruption (no demolition required)
- Lightweight foam prevents additional settling
- Smaller drill holes than traditional mudjacking
- Waterproof and durable material
- Long-lasting solution
4. What Kinds of Concrete Can Be Lifted with This Method?
Polyurethane concrete raising is suitable for various surfaces, including:
- Sidewalks
- Driveways
- Garage floors
- Basement floors
- Patios
- Pool decks
- Warehouse slabs
- Airport runways
- Roads and highways
If the slab is in relatively good condition (i.e., not cracked or crumbling), it’s likely a good candidate.
5. How Long Does the Process Take?
Most residential projects are completed in 1–2 hours, depending on the size and complexity. Better still, the concrete is ready to use within 15–30 minutes after the injection, making it a perfect solution for high-traffic areas.
6. How Long Does Polyurethane Foam Last?
Polyurethane foam is incredibly durable and resistant to water, chemicals, and erosion. With proper installation, the foam can last for decades. In most cases, it outperforms mudjacking slurry and prevents further settling better.
7. How Much Does Polyurethane Concrete Raising Cost?
Costs vary by region, project size, and the extent of the settling. On average:
- Small projects (e.g., a sidewalk slab): $300–$600
- Medium projects (e.g., driveways): $800–$2,000
- Large projects or commercial work: $3,000+
While it may cost more upfront than mudjacking, the durability and performance often make it a better long-term investment.
8. Is This Method Better Than Mudjacking?
Yes, in most cases. Here’s how polyurethane raising compares:
| Feature | Polyurethane Foam | Mudjacking |
|---|---|---|
| Hole Size | Small (5/8 inch) | Large (1.5–2 inches) |
| Weight | Light | Heavy |
| Cure Time | 15–30 minutes | 24–48 hours |
| Durability | Excellent | Moderate |
| Waterproof | Yes | No |
Mudjacking may still be suitable for some large-scale or low-budget projects, but polyurethane offers better overall performance.
9. Is Polyurethane Environmentally Friendly?
Yes, many polyurethane foams are made with recycled materials and reduce the need for full concrete replacement—minimizing waste. Also, by fixing existing slabs instead of removing and dumping them, you significantly reduce your environmental footprint.
10. Will It Damage My Concrete?
No. In fact, it helps preserve your existing slab. The small holes drilled into the concrete are patched after the procedure, leaving a clean appearance. Because the process is non-invasive, there’s very little risk of cracking or damage when performed by professionals.
11. Is Polyurethane Concrete Raising Safe?
Absolutely. Polyurethane foam is inert, meaning it’s chemically stable and non-toxic once cured. It’s safe for homes, businesses, and even food-related environments when installed correctly.
12. Can I Do It Myself?
While DIY polyurethane kits are available for very small jobs (like fixing voids under pavers), lifting concrete slabs is not a DIY-friendly project. The process requires specialized equipment and expertise to ensure the slab is lifted evenly without cracking.
Hiring a professional ensures:
- Proper injection depth and pattern
- Level lifting without damaging the slab
- Long-term performance and warranty
13. What Causes Concrete to Sink in the First Place?
Concrete settles for several reasons, such as:
- Erosion of soil due to water runoff
- Improper soil compaction during construction
- Freeze-thaw cycles causing ground movement
- Tree roots disrupting slab placement
- Heavy loads stressing the subgrade
Identifying and addressing the cause is crucial for preventing future issues.
14. Can Polyurethane Foam Fix Cracked Concrete?
If the cracks are minor and the slab is still structurally sound, yes—it can help. However, severely broken or crumbling slabs may require replacement. Foam lifting can correct unevenness, and cracks can be filled and sealed afterward for appearance and protection.
15. Will the Foam Wash Away Over Time?
No. Unlike mudjacking slurry, polyurethane foam is hydrophobic and resists water infiltration. It stays in place, retains its shape, and won’t erode or dissolve over time.
16. What Happens If the Concrete Sinks Again?
This is rare if the job is done correctly, but if it does happen:
- Some companies offer warranties or free re-lifting for a period
- A re-injection is usually possible without major extra cost
- Long-term issues often relate to underlying soil problems, so addressing drainage or root issues can prevent recurrence
17. Is the Process Noisy or Messy?
Not at all. The equipment used is compact, and the job site is usually clean. There’s minimal noise, no jackhammering or heavy demolition, and the area is restored quickly.
18. Can Polyurethane Foam Be Used Indoors?
Yes. It’s a great solution for interior slabs like basement floors, warehouse floors, and even hospital or commercial office spaces. Because the foam is odorless and sets quickly, it’s safe for indoor environments.
19. How Do I Choose the Right Contractor?
When hiring a polyurethane concrete raising specialist:
- Look for experience and certifications
- Check online reviews and before/after photos
- Ask about warranties and insurance
- Request a detailed estimate and inspection
Avoid companies that offer suspiciously low bids or can’t explain the process clearly.
20. What Should I Do After the Job Is Done?
After the lifting is complete:
- Avoid heavy loads on the slab for a few hours
- Seal any visible cracks to prevent water entry
- Monitor drainage to avoid erosion under the slab
- Maintain nearby landscaping to reduce root intrusion
Final Thoughts
Polyurethane concrete raising is a modern, efficient solution for lifting sunken or uneven concrete. It offers durability, speed, and minimal disruption, making it an ideal choice for both homeowners and commercial property owners. Whether you’re dealing with a trip hazard on your sidewalk or a sinking driveway, foam jacking could be exactly what you need.
If you’re considering concrete repair, don’t let unanswered questions stop you. Use this FAQ as your go-to guide and reach out to a qualified contractor to assess your needs.
