Polyurethane concrete lifting—also called polyjacking or foam jacking—raises sunken slabs by injecting a two-component rigid foam beneath them through 15–16 mm (5/8") ports. The foam expands within seconds, compacts loose soil, fills voids and lifts the slab back to grade. For contractors moving from mudjacking, or entrepreneurs entering the concrete repair trade, the injection rig is the core capital decision: it determines lift precision, daily job count and material yield.
A production-grade rig comes down to five decisions: proportioner accuracy, sustained output under a full hose run, heater response time, hose reach, and the total cost of ownership behind the sticker price. Contractors and equipment buyers comparing quotes need firm answers on all five before signing a purchase order—this is not a homeowner-level purchase.
What a Polyurethane Concrete Lifting System Consists Of
A complete rig is more than a pump. A working setup includes:
* A plural-component proportioner (the metering and mixing heart of the system)
* Independent A-side and B-side heaters plus a heated hose, typically 15–60 m
* An impingement-mix injection gun with slab adapters and port fittings
* Transfer pumps for drums or totes of isocyanate and polyol
* An air compressor and a generator sized to the heaters' draw
* A trailer or box-truck build-out that keeps chemical within storage temperature
The proportioner is the same machine class used for spray foam insulation: a high-pressure unit running roughly 1500–2500 psi with impingement mixing at the gun. Many contractors run one rig for both slab lifting and spray insulation to keep the asset earning year-round—if that is your plan, confirm the unit accepts both slab-lifting and spray-foam formulations before purchase. See our PU spray foam machine line for the shared platform, and the high-pressure PU foam machine range for the proportioner itself.
The Specifications That Decide Lift Quality
Mix ratio accuracy. Slab-lifting foams run at 1:1 by volume. Ratio drift beyond ±2% produces foam that under-expands, stays soft or cures brittle—under a slab, that means an incomplete lift you cannot see and a callback you will pay for. Insist on a proportioner that holds ±1–2% and alarms on deviation.
Output. Rigs in the 6–12 kg/min class cover residential and light commercial slabs. Highway, warehouse-floor and dock work favors higher sustained output so large voids fill before the first pass gels. Buy for sustained output with a full hose length, not the peak brochure figure.
Temperature control. Lifting foams typically want material at roughly 45–65°C at the gun. Underheated chemical mixes off-ratio and expands late—the foam keeps rising after you stop injecting, which is how slabs get over-lifted. Independent A/B heaters and a heated hose rated for your climate are non-negotiable for cold-season work.
Foam density and reaction profile. The machine must pair with the right chemical system. Void-fill and lifting foams run free-rise densities of roughly 3–6 lb/ft³ (48–96 kg/m³), with fast gel times so the lift is controllable in small increments. Geotechnical deep-lift systems differ from slab-lift systems; confirm your supplier supports both if your market includes soil stabilization.
Polyurethane Lifting vs Mudjacking: the Equipment View
| Attribute | Polyurethane lifting | Mudjacking |
|---|---|---|
| Injection port size | 15–16 mm (5/8") | 38–50 mm (1.5–2") |
| Material weight added to soil | ~48–96 kg/m³ | ~1800–2400 kg/m³ |
| Cure to traffic | 15–30 minutes | 24–72 hours |
| Lift precision | Millimeter-level increments | Coarser |
| Crew size | 2 typical | 2–3 |
| Capital cost | Higher | Lower |
| Price per job commanded | Higher | Lower |
The equipment costs more than a mud pump, but the business case rests on same-day return to service, smaller ports, no added soil load and premium pricing. Most contractors who switch do not switch back.
Cost of Ownership: Where the Money Actually Goes
The proportioner's sticker price is the smallest line in a five-year budget. Plan for:
* Chemical sets. Drum sets of A/B material are the dominant variable cost; yield per set decides your gross margin per job.
* Gun consumables. Mix chambers, port adapters, screens and O-rings wear on every job.
* Heated hose. A field consumable under trailer abuse; price replacement segments before you buy.
* Truck or trailer build-out. Generator, compressor, drum heating and racking commonly add a significant share on top of the machine itself.
When you compare quotes, request a spare-parts price list and maintenance interval schedule alongside the machine price. A cheap rig with proprietary, slow-shipping consumables is the expensive option within eighteen months.
Safety and Compliance
The A-side is isocyanate, a respiratory sensitizer. Crews need the exposure controls and respiratory protection described in OSHA's isocyanates guidance, and chemical handling should follow the practices published by the American Chemistry Council's Center for the Polyurethanes Industry. Injection under slabs is lower-aerosol than open spraying, but drilling, gun purging and trailer chemical transfer still demand PPE and ventilation discipline. Factor training into your launch plan, not as an afterthought.
Supplier Checklist Before You Sign
* Does the proportioner hold ±1–2% ratio with an alarm, and log shot data?
* Sustained output at your hose length—demonstrated, not quoted?
* Are slab adapters, deep-lift tooling and spray-foam conversion parts available?
* Spare-parts list with prices and lead times in writing?
* Commissioning support: startup, first-job supervision, operator training?
* Voltage and heater draw matched to the generator you plan to run?
* Warranty terms that survive field use, not just bench use?
Frequently asked questions
Can one machine do both concrete lifting and spray foam insulation?
Yes, in most cases. Both applications run on high-pressure plural-component proportioners. Switching involves changing chemical sets, flushing per the manufacturer's procedure and swapping the gun configuration. Confirm the specific model supports both formulations' viscosity and temperature windows.
What size machine does a startup slab-lifting contractor need?
A unit in the 6–9 kg/min class with a 30 m heated hose covers residential driveways, sidewalks and garage slabs. Move up in output only when commercial floor and roadway work is actually on your order book.
How much foam does a typical job use?
It depends entirely on void volume. A modest residential slab may consume a few tens of kilograms; large voids under commercial floors consume drum sets. This is why metering accuracy and data logging matter—they are your material cost record per job.
Is the injected foam permanent?
Rigid closed-cell polyurethane is dimensionally stable and does not shrink or wash out under normal ground conditions. Long-term performance depends on correct density selection and on-ratio processing—equipment factors, not just chemical factors.
Get a Rig Specification and Quote
If you are pricing equipment for slab lifting, void filling or soil stabilization—or want one rig configured to run both lifting foam and spray insulation—tell us your target job types, daily volume and power situation. The Pioneer engineering team will come back with a matched proportioner spec, tooling list and a like-for-like quote including consumables and maintenance intervals. Send your requirements through the contact page or browse the full PU machines range first.