It is no fun putting a ton of time and energy into pouring concrete only to have it crack a few months later. More than one DIY homeowner has experienced this very thing. The good news is that cracked concrete is avoidable. Most cases of cracking would not have occurred had homeowners done things a little bit differently.
In Salt Lake City, the Concrete Raising Company assists homeowners with concrete repairs on a daily basis. They know a thing or two about what causes concrete to crack. They recommend a few simple things that homeowners can do during the installation process to minimize the risks.
Properly Compact the Soil
One of the most common causes of cracking is sinking. Slabs, foundations, and steps can all sink if the soil underneath begins to give way. And when concrete sinks, it also cracks. Avoid both problems by properly compacting the soil before the actual pour.
Understand that concrete is essentially artificial rock. It is heavy. As such, the soil underneath needs to be strong enough to support its weight. You compact soil in order to increase its density and, subsequently, its ability to hold up heavy concrete. Failing to compact the soil virtually guarantees it will erode over time. Then the concrete above will sink and potentially crack.
Ensure Proper Drainage
Concrete is also a porous material. It can absorb some water, but not a lot. This suggests that you need to ensure proper drainage during the design stage of a new concrete pour. You want water to flow off and away from the concrete. You do not want it to puddle.
Puddling water can be a problem because it seeps down into the small pores of the concrete. That water can expand and contract with the temperature, thus leading to cracks. Indeed, this problem is especially pervasive in northern environments that frequently see cold temperatures during the winter months.
Get the Mixture Right
There is another cause of cracking that cannot be fixed with slab leveling or better drainage. What is it? Improperly mixed concrete. Know that concrete is a mixture of aggregate, sand, Portland cement, and water. The dry ingredients in the bag should already be properly mixed. All you have to do is add water. However, too much or too little water can cause problems.
You start by following the mixing instructions printed on the bag to the letter. But understand that you might have to make adjustments. If you are pouring concrete on especially hot or windy day for instance, you may have to keep the top surface of the slab moist with a garden hose during the early stages of curing. Otherwise, water could evaporate too quickly and cause a problem known as plastic shrinkage. Cracks may result.
Stay Off It for a While
Finally, you can create unnoticeable internal cracks by using freshly poured concrete too soon. Those internal cracks could eventually make it to the surface. You can avoid this sort of thing by staying off new concrete for a while.
Again, follow the instructions printed on the concrete mix bag. In most cases, a couple of days should be sufficient. If you poured a rather large slab and the weather hasn’t cooperated, you might have to wait a week or longer. The goal is to give the concrete enough time to completely cure before it has to accommodate a load.
The Concrete Raising Company encourages Salt Lake City residents to follow the basic rules of pouring concrete to avoid cracks. Those same rules apply everywhere else, too.