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Cracked Piers – Don’t Panic

A building inspector recently told a young couple that were buying a house, “The piers are cracked. You need a structural engineer.”

What does that mean? Why do piers crack? What can a structural engineer do?

Building Inspector Report

When a building inspector reports that piers are cracked, they could be the concrete stumps under an older style low set house, or they could be engaged brick piers that make up part of a brick perimeter wall. Either way, the problem the

Photos of a cracked concrete pier
Cracked pier caused by corrosion of reinforcement

inspector is referring to is informally known as “concrete cancer”, ie corrosion of steel reinforcement.

Steel reinforcement corrodes when it is too close to the external surface of a concrete pier or brick pier. The effect is similar in both cases. The products of corrosion, rust, have a greater volume than the original steel. The steel grows in volume and pushes outwards. This causes the concrete or brickwork to crack. The cracks allow more air and more moisture into the pier. The corrosion process continues and accelerates.

Replacing Cracked Concrete Piers

If you have cracked piers you probably need a structural engineer to help solve the problem.

Short stumps under a low set house can be easily replaced with galvanised steel posts in a new concrete footing.  A structural engineer can specify what steel post to use and how big the footing needs to be. Check with a certifier to see if you need building approval for your project.

Repairing Cracked Brick Piers

For brick piers, the problem is somewhat more complicated. Stopping the corrosion in a brick pier is difficult. A structural engineer will help you identify the cause of the corrosion and can write a specification for the repairs or replacement of the cracked piers.

Cracked concrete stump under a house

Continuing Our Story

For the young couple, they decided to go ahead with their purchase. They have scheduled some post replacement weekends to replace the cracked piers under their house and they’re enjoying their new house.

Don’t Panic

Don’t panic if your inspector tells you you have some cracked stumps. Call Cornell Engineers. We’ll help you work out why the piers are cracked and the best way to fix them.

By Matt Cornell
Cornell Engineers