Polyjacking: Fast, Lightweight Slab Lifting with Polyurethane Foam

Carbon fiber straps are high-tensile-strength composite straps bonded vertically to the face of a bowing basement wall to prevent further inward deflection. The straps are made from the same carbon fiber used in aerospace and structural engineering applications, rated at tensile strengths far exceeding steel by weight. When epoxy-bonded to a properly prepared wall surface from floor plate to sill plate, carbon fiber straps transfer the lateral soil pressure load into the top and bottom bearing points of the wall system rather than allowing the wall face to deflect. Carbon fiber reinforcement is best suited for walls that have deflected less than 2 inches and have not experienced significant cracking through the wall section. It is a hold-in-place system, not a restoration system, it prevents further movement but does not push the wall back toward its original position.

Deep foundation systems transfer structural loads from the ground surface to soil or rock at a depth where bearing capacity is reliable and unaffected by surface conditions. In Middle Tennessee, the primary driver for deep foundation work is the region's expansive clay geology: the top several feet of soil shrink in dry weather and swell in wet weather, making them unreliable bearing material for foundations that must remain stable year-round. Deep foundation elements including helical piers, push piers, and micropiles penetrate through this active zone and reach bedrock, dense gravels, or competent clay at depth where moisture variation has minimal effect. These systems are used for both new construction on difficult sites and for repair of existing foundations that have settled due to inadequate bearing in the near-surface soils. Ground Up designs and installs deep foundation systems for residential and light commercial applications throughout the Middle Tennessee region.

Epoxy crack injection is a structural repair method for concrete foundation walls, slabs, and beams that have developed cracks due to settlement, curing shrinkage, hydrostatic pressure, the outward force of water pushing against a foundation wall from saturated soil, or thermal movement. Low-viscosity epoxy resin is injected under low pressure through surface ports installed across the crack at regular intervals, filling the crack from its deepest point outward. As the epoxy cures, it bonds the two concrete faces together with tensile strength greater than the surrounding concrete. The result is a monolithic repair that restores the structural continuity of the cracked section. Epoxy injection is appropriate for dry or dormant cracks, cracks that are not actively wet and not in active movement. For cracks with active water seeping through them, polyurethane foam injection (which expands and seals in the presence of moisture) is often the appropriate first step, followed by epoxy once the wall has been dried out.

Concrete is a rigid material that nonetheless moves with temperature, moisture, and loading. In Middle Tennessee's climate, with summer temperatures regularly exceeding 95 degrees and occasional hard freezes in winter, the thermal expansion and contraction of concrete slabs, driveways, sidewalks, and foundation walls is significant. When concrete cannot move freely, it builds up internal stress that is released suddenly as a crack. Expansion joints and control joints are planned gaps in the concrete that give it a place to move without cracking in the field of the slab or through a structural element. Ground Up installs expansion joints during new concrete work and cuts or installs retrofit joints in existing concrete to prevent crack propagation and protect adjacent structural elements from impact loading caused by slab movement.

Foundation underpinning is the process of extending the effective depth of a foundation's bearing capacity by installing structural support elements that bypass inadequate near-surface soils and transfer load to competent material at depth. In Middle Tennessee, where expansive clay soils lose and regain bearing capacity with every moisture cycle, underpinning is the most durable long-term foundation repair strategy available. Ground Up installs two primary types of underpinning: helical pier underpinning, which uses rotating steel shafts with helical plates to reach bearing at a torque-confirmed depth; and push pier underpinning, which drives steel pipe sections hydraulically using the building's weight as a reaction force, meaning the home's own weight gives the hydraulic ram something to push against, until the pier reaches refusal in competent soil or rock. Both systems transfer the structural load from the clay soils that are causing settlement to deep bearing material that is unaffected by surface moisture variation, stopping settlement and in most cases allowing partial to full elevation recovery.

Concrete piers are cast-in-place or pre-cast reinforced concrete elements that extend from the foundation footing down through unstable near-surface soils to a bearing stratum with adequate capacity. They are one of the most durable underpinning approaches available for residential and commercial foundations in Middle Tennessee, providing a permanent structural connection between the foundation and the stable soil or rock below the depth at which seasonal and moisture-driven soil movement occurs.