A strip footing is a continuous concrete footing that runs beneath a load-bearing wall, spreading the wall’s weight evenly along its entire length rather than at isolated points. It’s the most common footing type for residential foundation walls, since walls apply a continuous, linear load that a strip of concrete distributes efficiently.
Strip footings are typically formed and poured before the foundation wall itself, with reinforcing steel tied in place to resist both bending and shrinkage cracking as the concrete cures.
What Does a Strip Footing Involve?
- A continuous concrete strip beneath a wall
- Width and thickness sized to the wall’s load and soil bearing capacity
- Reinforcing steel running along its length
- Placement below the local frost depth
Why Is a Strip Footing Important?
A strip footing that’s undersized for the soil conditions or the wall load above it can lead to uneven settlement along the wall’s length, showing up as cracks that run horizontally or diagonally through the foundation. Because it runs continuously, a strip footing also helps bridge minor variations in soil conditions along a wall’s length, distributing load more evenly than isolated points would.
This continuity is particularly valuable on sites where soil quality isn’t perfectly uniform, since a strip footing can transfer some load away from a locally weaker pocket of soil toward adjacent, stronger sections rather than concentrating stress at one point. Contractors typically pour these footings using removable wood or metal forms set to the engineered width, checked for level before the concrete is placed.
Strip Footing vs. Isolated Footing
A strip footing runs continuously beneath a wall, while an isolated footing supports a single point load, like an individual column. Buildings often use both together: strip footings beneath the perimeter walls and isolated footings beneath interior columns carrying concentrated loads, each sized independently for the specific load it needs to carry.