No Foundation

The Problem

Some older houses were built on wood beams laid directly on the ground, without foundations. These houses may shift during earthquakes, causing structural damage and breaking utility lines.

How to Identify

Look under the house. If you see no concrete or masonry around the outside walls, the house may lack a foundation.

What Can Be Done

You may need to add a foundation to make the house earthquake resistant. Just as when strengthening or replacing an unreinforced masonry foundation, you will require the advice of a licensed architect, engineer, or foundation contractor.

Old Concrete Foundation

The Problem

Some older concrete foundations were made with sand or stone that interacted chemically over time, and the concrete eventually crumbles and becomes too soft to withstand earthquake forces.

How to Identify

Inspect the foundation for large cracks in the concrete, concrete crumbling off the foundation, or concrete crumbling when you pick at it with a screwdriver.

What Can Be Done

You may need to replace some or all of the foundation. You should consult a licensed foundation contractor or an engineer.