How Not to Get Your Concrete Patio Cracked

Concrete patios are an attractive addition to any home and are durable, cheap to build, and attractive in appearance. Yet even firmly installed patios suffer from the effects of the elements over time if they are not built, maintained, and sealed properly. The good news? Cracks can be avoided: with a little thought and action, you can preserve your concrete investment and patio for many years.  

In this instruction manual, we’re going to tell you all about why cracks occur (telling us why this should happen is interesting), and even more importantly—how to prevent them; from planning through maintenance over the long term.

Why Concrete Cracks

Before we talk about preservation, it's important to have some background. Here are five common causes of your concrete patio cracking:

- Shrinkage – The concrete contracts as it dries and hardens. If drying happens too rapidly or unevenly, cracks will show themselves.

- Settlement – The soil under a slab suffering uneven settlement could provide points of stress.

- Temperature Changes – Expansion and contraction caused by environmental changes is problematic.

- Overloading – Overburdened, stressed to breaking point, a slab can fracture.

- Faulty Installation – Whether control joints are lacking altogether or cutting poorly done and pouring unevenly, each of these errors can lead to decreased strength in the patio.

Knowing these problems is your first step in prevention.

1. Give a Good Beginning  

The foundation—or subgrade beneath your patio—is just as important as the concrete. Make sure you have a good foundation.

   Suggestion:

   - Soil Compaction: Soft or uneven soil is likely to compact under the weight you place on it given time when it goes for the concrete pad above. A good rule of thumb is never to load soil that has not been compacted by first stamping down with a plate compactor.

   - With crushed stone or gravel below the slab, you'll get better drainage and less settling.

   - Level It Properly: Make sure the base is level and sloped downhill.

   Skipping these essential steps has been a major reason for trouble in the long run.

2. Use Quality Concrete Mix  

Not all concrete mixes are created equal. The life and fitness of your patio is reliant to a large extent upon which mix you choose.

   Tips:

   - Choose a Mix with Lower Water Content: Too much water weakens the concrete and increases the chances of shrinkage cracks.

   - Use Reinforced Concrete: Adding rebar or wire mesh helps minimize cracking and increases strength.

   - Additives: Fiber or other admixtures can decrease shrinkage and increase flexibility.

   If you are engaging a contractor with an offer of PSI rating (standard measure for the strength of concrete), a minimum of 4000 PSI is recommended for outdoor patios.

3. Install Expansion Joints  

Concrete shrinks during curing—that's a fact of life. Expansion joints let you choose where to direct the cracking.

   Spacing: All 8-12 feet apart, there should be a control joint in each direction.  

   Depth: Joints should be at least one-quarter the thickness of the slab (e.g., 1 inch deep for a 4-inch slab).  

   Timing: These should be cut or tooled into the surface within 6 to 18 hours after pouring in order to work.  

   Finally, think of control joints as “planned” weak spots that encourage the concrete to crack along a line instead of haphazardly.

4. Watch the Weather  

For the curing process, weather plays a crucial part. Both hot and cold temperatures present their own dangers.

   Tips:

   - Professional Opinion: Hot concrete pours are not ideal in hot weather, drying very quickly and causing shrinkage cracks to appear. Consider deploying shade cloths or water misters when the thermometer rises.

   - Protect from Rain: Puddles of rain on freshly laid concrete will make your surface look horrible. Cover your project with a sheet of plastic until it's cured.

   - Parking in Cold Areas: Water that gets into and then freezes inside concrete can cause serious problems. Use atmospheric air-filled concrete to guard against this kind of issue.

   Some people say that if you fail to look at the weather forecast, your cement pour will be a miserable failure. Timing is everything! Always check the weather channel before scheduling your concrete pour.

5. Carefully Curing the Project 

Curing is the process that allows concrete to develop its strength. Don't rush this step: if you cut corners here, then not only will your surface be less strong than it might otherwise have been, but it could also easily crack.

   Tips:

   - Keep It Wet: You need to keep moisture on concrete for at least 7 days. There are several things you can do to achieve this. Watering with a hose, sprinkler system, or just putting wet burlap down in the mornings will all work.

   - Use a Curing Compound: Curing compounds are applied just after the surface has turned color. This final touch can help to maintain humidity and reduce the risk of cracking.

   - Stay Off It Too Soon: Most concrete patios need at least 24–48 hours before you can use them lightly for walking and 7+ days before you set furnishings or planters on them.

   Proper curing is a bit slow, but it's also probably the best way to prevent early cracks from sprouting up.

6. Keep Off the Patio  

Concrete is very strong, but it is not indestructible. The strain of excessive or even uneven weight can easily cause damage to your project—usually at slab edges more than anywhere else.

   Tips:  

 - Be Kind to Heavy Objects: Don't put hot tubs or heavy grills next to the edge of the slab. If a large potted plant stands in an area that's not well supported, you'll get the same issue.

   - Balance Weight: Underneath all that furniture and mechanical equipment, pad out your space with cement slabs or pavers so your load can be distributed as easily as possible.

   - Automobiles Must Wait: Unless your patio is specifically designed to accommodate them, don't drive your car or truck onto it.

   Know your slab's design characteristics and take care to protect it.

7. Seasonal Maintenance and Other Details

   - Spring: Remove leaves and debris; reseal if needed; examine for gaps in the concrete.

   - Summer: Check for pools of water or discoloration from sun damage. Use umbrellas, awnings, or other coverings to protect the material.

   - Fall: Clear off leaves and prepare the concrete for winter by applying a new coat of sealant to the surface.

   - Winter: Keep away from deicing salts. They can harm the concrete. Shovel snow with a plastic (not metal) shovel.

8. Fix Small Cracks IMMEDIATELY  

Despite your best efforts and those of the professionals who built it, small cracks can still develop. Respond early with a repair because otherwise they will grow and split your project apart.

   Fixing Small Cracks:

   - Clean the crack out completely.

   - Use a concrete crack filler or a patch mix to fill the void.

   - Smooth with a trowel and let it cure.

   - If necessary, reseal the surface to prevent dirt from penetrating further into any possible moisture-control system that might be present in the concrete.

 Think of maintenance for cracks as routine as cleaning gutters or repainting your trim.

Closing: A Crack-Free Patio Starts with Prevention

What follows here are some tips for saving energy and materials in the long run if you are properly prepared. Use quality mixes, compact the soil, and do everything else you can to help place your concrete right—from the ground up. With good preparation, the right materials, and follow-up care through its lifetime, your effort will stand as strong and clean looking in 20 years as it is now. If you’re planning a new patio or concerned about cracks in your current one, don’t go it alone. Work with a professional concrete contractor who knows how to install and maintain settings properly, such as HBT Concrete. With experienced help and a little know-how, you can build a space that stands the test of time—without cracks.