What is Raising, Grading and Elevating?

In the context of foundation repair, raising, elevating, and grading are distinct processes that address different aspects of a building’s stability, primarily in relation to the soil and water around it.

Raising & Elevating

These terms are often used interchangeably to describe the process of lifting a sunken or settling foundation back to its original, level position. This is a direct, structural repair.

  • Why it’s done: Foundations can sink due to unstable soil, soil expansion and contraction from moisture changes, or improper soil compaction during construction. Raising or elevating the foundation corrects this unevenness.
  • How it’s done: Professionals use methods like piering (also known as underpinning) where steel or concrete piers are driven deep into the ground until they hit stable soil or bedrock. Hydraulic jacks are then used to carefully lift the foundation and transfer the weight of the structure onto these new, stable supports. Another method is slab jacking or polyurethane injection, where a grout mixture or expanding foam is injected under the slab to fill voids and lift the concrete.

Grading

Grading is the process of shaping the ground around a building to ensure that it slopes away from the foundation. It is a crucial preventative measure and often a key part of the repair process.

  • Why it’s done: Poor grading, where the ground slopes toward the house, allows water to pool near the foundation. This excess water saturates the soil, causing it to swell (hydrostatic pressure) or erode, which leads to foundation movement and damage.
  • How it’s done: Positive grading is achieved by adding soil and compacting it to create a slope that directs water away from the foundation. The general rule is to have a slope of at least 1 inch per foot for the first 5 to 10 feet away from the building. This can also involve installing drainage systems like French drains or extending downspouts to carry water further away.

Relationship: While raising/elevating fixes the symptoms of a failed foundation, grading addresses the root cause: water and soil issues. A professional foundation repair often includes both: first, lifting and stabilizing the foundation, and then correcting the grading to prevent the problem from reoccurring.