Concrete Deck Repair: How to Fix Cracks in Concrete

What You'll Need
Cleaning agent, such as trisodium phosphate (TSP)
Safety gloves and goggles
Patching concrete
Scrubbing brush
Water-based sealant

Discovering a crack big enough to warrant concrete deck repair can be very frustrating. It may cause you an immediate desire to contact a contractor who can undertake a repair. However, you can also complete the work yourself by following the steps below.

Step 1 – Note the Weather

Undertaking a concrete deck repair in any extremes of weather will only yield poor results because the concrete will not adhere correctly. Hot and sunny conditions will cause the concrete to dry too quickly and shrink away from the sides. Weather that is too wet will not give the concrete the opportunity to dry. Conditions that are too windy can thwart your attempts to protect the repair and may leave ripples in the wet concrete.

Step 2 – Examine the Area

To ensure that the concrete deck has not sustained more cracks than you realize, examine the entire deck carefully. Check for any cracks within joins and hidden sections. This examination will allow you to complete the entire concrete deck repair at the same time.  

Step 3 – Choose the Concrete

Once you have examined the area, you will be in a better position to decide which type of concrete you need because you will be aware of the severity of the cracks. You can complete more superficial concrete deck repair with concrete filler, which is available at most hardware stores. Deeper cracks and more major damage may require a concrete that you mix. A variety with a high lime content will be more flexible and therefore best to use for repairs.

Step 4 – Prepare the Area   

Before breaking out the cement, you must prepare the surface by thoroughly cleaning it. For deep cracks, remove any pieces of loose cement with a hammer and chisel if necessary. Once you complete this process, you can treat the deep crack in the same manner as smaller ones.

Clean the area to be rectified with a TSP-based cleaning agent. TSP is available as a stand-alone product from most hardware stores. You should mix one part of the agent with four parts of water to make a solution ideal for scrubbing the area.

Step 5 – Mix and Pour the Concrete

If mixing the concrete for the concrete deck repair, do so in accordance with the manufacturer’s instructions when you're ready to use it. Carefully pour the cement in small increments so you do not risk overfilling the crack. Use a trowel to smooth the surface of the wet cement.

Step 6 – Protect Your Work

Leave the cement to dry for at least 24 hours. Cover it with a scrap piece of cardboard and cordon it off while it dries. Once the concrete is dry, cover it with a suitable water-based sealant to prevent any water damage or staining.