Slabjacking has many advantages over slab removal and replacement.
When approaching a new job, the slabjacking contractor first assesses the settlement of the slab. Inadequate subgrade compaction isn't the only cause for settlement of concrete slabs on ground.
If the sunken slab must be isolated, the contractor may use sawcuts at joints to relieve binding. Surveying equipment and grade and string lines are used to establish the correct elevations. Then the contractor drills holes in the existing concrete slab or floor using a diamond bit or a percussion drill with a carbide bit.
The contractor hydraulically pumps a grout mixture through the holes and into the voids beneath the concrete. The pumped grout mixture fills the void, exerts pressure on the concrete and the subsurface material, and lifts the slab. During the lifting operation, the operator monitors both volume and pressure.
Slabjacking must be performed with controlled and even pressure grouting to prevent cracking. Once the concrete is properly aligned and leveled, the drill holes are patched.
While driveways, sidewalks, pool decks, and other residential repairs remain the bread-and-butter work for slabjacking contractors, commercial, manufacturing, and roadwork are often well suited to the advantages of slabjacking. Often, " slabjacking is the best alternative to the mess, noise, and downtime of demolition work," advises Darrel Maute, A-1 Concrete Leveling, Belleville, Mich.
The alternative to slabjacking is demolition of the existing concrete and construction of a new slab. Slabjacking has many advantages over such drastic measures:
- Low Cost
- Little mess
- Minimal downtime
- Waste disposal
There are also some reasons to proceed with caution:
- Underground utility lines
- Slab drift
The most important factors are the pump and the grout mix. The most common types of pumps used for slabjacking or pressure grouting are rotor stator pumps, ball valve pumps, and swing valve pumps.
Most slabjacking contractors and some manufacturers provide their own training.