This week we discuss how to fix puddling from improper concrete laying or settling.
Q: I laid a concrete slab in my backyard last year for a one-sided basketball court for the kids. After it rains there is a lot of sitting water in the middle of the pad. It’s not that big so I’d rather not tear it out. How do I repair it? – Tim Reese
A: Thank you for your question Tim! This is a pretty common issue to have, as there are a lot of physical factors at play when laying concrete. Much of it depends on what caused the uneven concrete in the first place. The first step is to determine what is causing the sitting water.
What You Should Know First
DIY repair jobs on concrete can be hit-and-miss. There are multiple reasons for this: the color of the existing concrete may be different from the new concrete. Additionally patches may not last as long as an original concrete pour. Lastly, it can be difficult to level the concrete patch accurately. Weigh your options – you can do a DIY job now, but you will someday probably need to replace the pad. With that said, if you are still comfortable with proceeding, read on!
Determining The Cause
Photo Credit: Vesta Foundation
Firstly, you must determine if the concrete is bowing down due to settling or puddling.
1. Often occurs in areas where water accumulates.
2. Often has a ‘trajectory line’ where the settlement occurs; for example, if it occurs in one square foot you will probably see settlement nearby in a linear pattern or patches.
3. Makes the concrete look cracked or ‘spider-webbed’.
1. Often difficult to see without using levels.
2. Gives a more smooth appearance than settlement.
Standing water from puddling.
Photo Credit: allgaragefloors.com
From the question it sounds like this is not concrete settlement but rather puddling. If, by chance, your concrete has settled it is much more difficult to fix than puddling. If your cement is settling, then the larger concern is that the soil beneath your basketball pad is moving. You can add to it, as we will discuss in puddling, but the larger concern is with the fact that it will probably do it again.
If you experience settlement, we recommend contacting a professional who will come in and raise the basketball pad. This is much easier and safer than doing it by yourself. We also urge you to check around other places on your property to ensure your home isn’t experiencing any settling also. You can read more about settling here.
From here, we will discuss how to fix puddling.
Clean It Thoroughly
The first step is to clean that pad deeply. Any grime, even smaller particles, can cause problems with laying a patch. A pressure washer is great to use. Spray it down, then spray it again. You want the water coming off the pad absolutely clear. Depending on the depth of the puddle, you may need to do a more thorough preparation job, such as an acid etch.
If you don’t have a pressure washer a hose will work, but you will need to wash, rinse, and repeat over and over again. Taking a scrub brush to the area might be a good idea.
Evaluate The Depth of Repair
If you have a very small amount of area that needs patched (i.e. less than one vertical inch) you can use something more liquid in nature. Anything above an inch in depth and you will want to have a thicker mix, including something with a bit of rock in it. You decide what kind of patch you want to apply, but know this cardinal rule that applies to much more than concrete – if you buy cheap, you reap cheap rewards. If you want a lasting job, buy quality patch materials. You can find these concrete mixes at pretty much any home improvement store, and will likely need just one bag for a smaller job.
1. Use a 2×4, or several, to lay across the puddling. This is going to act as your level – bringing the new patch up to the bottom of the board. This will ensure that your patch is level with the concrete around it. Note: Use discretion when using a level on your concrete pads. Sometimes concrete may not always be laid entirely level to begin with.
2. To prep the pad, soak the pad with water. Concrete is of course wet, but the water will seep down into the existing pad if it is not wet. Thus, you want to make sure the existing slab is saturated with water.
3. Mix the concrete (remember, thicker concrete for a thicker patch).
The two options: patch mix or a bonding agent. The patch mix works by itself; the bonding agent needs mixed with concrete. Available at Home Depot.
You first want to add a primer coat, then follow it up with the full patch (either a patch mix or concrete with a bonding agent). The combination will ensure proper bonding.
1. Mix the primer according to the instructions on the bag (remember, thick aggregate for larger patches, thin aggregate for thinner patches).
2. Place the primer in the patch area and smooth it with whatever is working best – a trowel, board, or another tool. For this portion the primer should be very thin. Just enough to cover the area lightly (around 1/8″ deep).
3. Combine the patch mix with water. Alternately, you can use normal concrete mix and a bonding agent. These should be near the concrete at the store. Use your best judgment in buying a concrete mix and the bonding agent.
4. Fill in the patch area and level it out with a trowel or 2×4.
5. Ensure that the patch lines up with the bottom of the 2×4(s) that you lined up as guides. Remember, the more time you spend ensuring the patch looks smooth, the better it will look when you are finished.
As soon as the new concrete is laid down, you will need to add a curing agent. This will help with the longevity of the patch. This is a liquid substance that is sprayed on top of the new concrete and can be found in the same place you purchase your primer, concrete, and bonding agent.
Concrete should stay put for about a week without being disturbed. This will ensure that your concrete hardens correctly.
After you have completed the patch, it should work as you originally intended. You may need to take additional steps to fix coloration issues.
Another issue that you may find is some newly laid concrete that still needs work. If it fixes the problem of standing water on your pad, and doesn’t pose a threat to injury by people playing ball on the pad, then it will probably be fine to be left alone. However, you are probably aware that there are multiple factors at play that can cause concrete cracking. Your patch may crack, so you may need to do several iterations, or fixes, to get a smooth pad. We will not explore more in depth here, but would refer you to a local professional or other guides on concrete cracking.
Vacuums For Concrete Cleanup
Understandably, working with concrete can be messy. We make vacuums that are specifically designed for concrete work and cleanup in two options: HEPA Wet+Dry and Wet+Dry Vacuums. HEPA vacuums filter out the smallest particles, including hazardous material such as silica from concrete. Our normal Wet+Dry Vacuums will still filter out small dust particles and is great for slurry work. Both types of vacuum can be used in cleaning up concrete slurry and concrete dust.