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Cold Joint

The cold joint occurs between the end of one concrete pour and the beginning of a new fresh concrete pour.

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A cold joint in concrete is likely to be a cause of concern for many homeowners in Virginia Beach, VA. The discontinuity between the content slabs often comes about as a result of the time delay in concrete pours, which results in poor bonding. Read on to find out how they occur, their effect on your home, and how to fix them.

What Is a Cold Joint?

A cold joint happens when fresh concrete is poured on top of existing concrete. It looks like a huge crack and some home buyers even mistake them for structural cracks or movements. The truth is that cold joints rarely create structural integrity issues, especially if they’re compressed. 

Mixing each batch of concrete typically requires some amount of manual work. Because of this, considerable time can elapse between successive pours. The lower pour will cure and harden before the next concrete pours. Because each layer has different chemical compositions, it may contract and expand at different intervals.

With time, there is a likelihood that the bond between the two concrete pours will weaken and this might create a frail zone in the voids. Talk to your foundation contractor if you feel something is wrong. They can identify the position and pattern of a cold pour joint and how it slopes by locating where the concrete was poured.

Problems Associated with Cold Joints

The inability of the two pours of concrete to combine creates a weak plane, which significantly affects the performance of a structural system. Some of the problems that may arise from cold joints can range from relatively mild to very serious and they include:

1. Reduced Strength of Concrete 

Concrete may be naturally strong, but it’s still frail under tension. A cold joint can weaken concrete floors, making them susceptible to damage at the discontinuity. This happens a lot when water gets into a cold joint. 

Are you wondering how? 

Water expands when it freezes and contracts when it thaws. This freeze-thaw cycle exerts pressure on your concrete walls and this can lead to cracks. 

2. Concrete Becomes Visually Unpleasing

Another common effect of a cold joint on your structure is that it may result in a visually unappealing discontinuity known as a cold joint line. This line is visible on the surface when the second layer of concrete starts to harden.

3. Leaks

When you pour wet concrete onto an existing block of concrete, the two won’t mix. This creates voids at the joint between the two adjacent pours. Such voids allow water to penetrate your basement walls, and this can lead to water damage. 

How to Fix Cold Joints in Concrete 

The good news is that you can fix cold joint issues. One way to correct a cold joint is by applying a joint sealant that makes it watertight. This protects the joint from water. Another way to strengthen the bond between two layers is installing reinforcing bars into the first layer before pouring a fresh one. Rebars will help tie both layers together and increase the tensile strength of the joint. 

Why Repair a Cold Joint?

There are many benefits to repairing concrete floors with cold joints. Sealing the joints stops water infiltration and makes your home dry and mold-free, making moisture issues a thing of the past.

Cold joint repairs also help preserve the structural integrity of your home. And this will in turn increase your home’s value. But that’s not all. You will also block radon gas and stop insects and rodents from moving into your home.

While cold joints in concrete foundations aren’t a structural problem, they can form dry joints that let water seep through your foundation wall. You need to hire a foundation contractor to inspect and fix them. If you need help, schedule a first free foundation repair inspection with JES Foundation Repair and get a no-obligation quote plus recommendations.

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