How much pressure is needed to lift a standard concrete slab?

Self-weight of a 4-inch slab is only about 0.35 psi. HMI states that less than 7 psi is typically enough to raise a standard slab.

Can polyurethane foam lift a thick concrete stoop?

Foam pushes with about ≈12psi lifting pressure. That is enough for most jobs. On the heaviest and most tightly stuck stoops (thick concrete + big underground overpour + binding to the house), the resistance can get close to 10 psi. In those cases, foam is working closer to its limit and has less extra force in reserve.

Why does pressure vary across a slab during the lift?

Peak pressure occurs only under the hole being injected. Pressure and material density drop with distance from that hole. On large slabs the areas between holes receive less pressure until the operator moves to them. Lift therefore occurs progressively as the operator “walks” the elevation across the slab.

Are the maximum thickness figures real field results?

These numbers are theoretical. They show the maximum thickness that could be moved at the active injection point if the full available pressure were applied there. They do not represent uniform pressure under a large slab or typical field results. Real performance depends on hole spacing, sequencing, and operator control.

How much pressure is needed to lift a standard concrete slab?

Self-weight of a 4-inch slab is only about 0.35 psi. HMI states that less than 7 psi is typically enough to raise a standard slab.

Can polyurethane foam lift a thick concrete stoop?

Foam pushes with about ≈12psi lifting pressure. That is enough for most jobs. On the heaviest and most tightly stuck stoops (thick concrete + big underground overpour + binding to the house), the resistance can get close to 10 psi. In those cases, foam is working closer to its limit and has less extra force in reserve.

Why does pressure vary across a slab during the lift?

Peak pressure occurs only under the hole being injected. Pressure and material density drop with distance from that hole. On large slabs the areas between holes receive less pressure until the operator moves to them. Lift therefore occurs progressively as the operator “walks” the elevation across the slab.

Are the maximum thickness figures real field results?

These numbers are theoretical. They show the maximum thickness that could be moved at the active injection point if the full available pressure were applied there. They do not represent uniform pressure under a large slab or typical field results. Real performance depends on hole spacing, sequencing, and operator control.