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DIY vs professional polyjacking
Yes, you can buy foam at a hardware store. No, it will not lift your concrete. Here's the honest breakdown.
The problem with DIY foam kits
Hardware-store expanding foam (window-and-door foam, Great Stuff, etc.) is a low-density, soft sealant — not a structural lifting foam. It expands at maybe 1–2 lbs/ft² of force. A car parked on a slab generates 30–80 lbs/ft². The math doesn't work.
Real polyjacking foam is a high-density, two-part structural polyurethane delivered through heated, calibrated equipment at 1,500–2,500 PSI. The material itself costs $30–$60 per pound and isn't sold to consumers.
What homeowners actually try
- • Sand or gravel "leveling": Pouring sand under sunken slabs through a hole — washes out within months.
- • Concrete patching compound on top: Hides the symptom but the slab keeps sinking.
- • Hardware-store foam: Compresses immediately under load.
- • Hydraulic jacks: Cracks the slab within minutes — point loading on concrete is catastrophic.
The real cost comparison
| Approach | Real Cost | Lifespan |
|---|---|---|
| DIY hardware foam | $50–$200 | Weeks (ineffective) |
| Sand washout fill | $100–$300 | Months |
| Professional polyjacking | $500–$2,500 | 10+ years |
| Replacement | $3,000–$10,000+ | 15–30 years |
When DIY is fine
Cosmetic crack filling, surface patching, and joint sealing are reasonable DIY jobs. Anything involving a sunken slab is not.
FAQ
Effectively no. Polyurethane lifting rigs are not part of standard rental fleets and the foam itself is sold only to certified contractors.