How to Repair Cracks in Your Precast Concrete Fence

Person repairing their precast concrete wall

Despite how precast concrete is one of the toughest building materials out there, sometimes things happen, and you might find a crack. The good news is most cracks are easy to fix. Here is the best 3 step process to fix the crack.

Before you start, assess the size and the number of cracks. If you have a lot of cracks, or if you keep getting cracks, you might need someone to assess the fence. Reoccurring or many cracks could be a sign that there is a structural issue with the fence.

Clean and Prepare

You can enlarge the crack slightly, but you don’t need to do this. No need to go crazy here; just make sure the crack is bigger for the grout to have somewhere to go. 

As we said, this is an optional measure unless you have a larger crack. You want to make the crack bigger with a chisel and hammer for larger cracks. This step ensures plenty of surface area for the grout to stick.

Now, make sure the area around the crack is completely clean. The goal here is to create a good surface for the grout to stick.

Clean off any dust, dirt, and white mineral buildup. Next, sand the area with 50-80 sandpaper. Take your time here to get things clean. The more effort you put in at this step, the longer and better the fix will last.

Next, you want to prepare the area for the grout. Do this by covering the crack with a wet fabric. Keep it wet for a few hours. If the wall is dry when you apply the grout, the wall will suck out all the water from the grout. If the wall does this, it could cause the grout to crack as it’s curing.

Apply Portland Cement Grout

After the area has been soaking for a few hours, it’s time to mix the grout. Mix Portland cement and water until you get a peanut butter consistency. You want to stir this continuously to stop it from forming lumps.

You can add some acrylic bonding agent, which will help the grout stick to the fence. This step is optional. Follow the mixing directions on the bottle.

Next, use a trowel to fill the crack with the grout. You want to pack the crack with the grout completely. Push the grout into the crack and around the crack. Once the crack is full, allow the grout to cure slightly. Then, skim over the grout with a clean trowel to smooth the surface.

Start Curing

Now, you need to allow the grout to dry for 2 to 3 hours. Once this time has passed, cover the area with a plastic sheet. Make sure you tape down the plastic sheet with duct tape. Over five days, come out to the fence and rewet the grout with a bit of water. When you’re doing rewetting the group, recover it each time with the plastic sheet and duct tape.

You want to apply a silane-based sealant to the crack repair. Go a few inches around the whole thing with the sealant and use a synthetic bristle paintbrush. 

Make sure you fix the crack as soon as you see it. A crack will allow water to seep in, quickly making it worse.

American Precast Concrete Inc. 

If you have any questions or want a professional to help you repair cracks in your precast concrete fence, please contact us. We look forward to helping you.