Tips About Self-Leveling Concrete
Self-leveling concrete can be a fast, cost-effective solution to the problem whenever you need to repair, smooth, or raise a floor.
What is Self-Leveling Concrete
Self-leveling concrete is a cementitious mixture, much like concrete. But unlike concrete, it flows easier and sets up much faster. The product is mixed with water, pumped or poured into place, and spread evenly with a gauge rake. Once it’s spread out, it continues to flow evenly and levels itself out.
Now that you know what self-leveling concrete is, in the article, we’ll discuss the following:
- How Long Does Self-Leveling Concrete Take to Harden?
- 7 Tips on How to Apply Self-Leveling Concrete
- Where Self-Leveling Concrete Is Used
- Cost of Self-Leveling Concrete
- Preparing to Use Self-Leveling Compound
- Troubleshooting Self-Leveling Concrete
- Takeaways for a Successful Self-Leveling Pour
How Long Does Self-Leveling Concrete Take to Harden?
Depending on the product, it may be smooth and flat within 1-2 hours. In about 6 hours, it may be completely hardened and ready for use, depending on the flooring material being installed on top. Self-leveling concrete can be used as an underlayment for tile, carpet, or other floor coverings.
Now, let’s clarify some things concerning product names. Instead of “concrete,” you might see products called “self-leveling underlayment.” This name means the same thing as “self-leveling concrete.”
They’re generally mixtures of Portland cement, polymer plasticizers, and other ingredients. They have the strength of concrete but flow more easily and are set up quickly.
Self-leveling concrete can be poured as thin as a quarter of an inch, just enough to smooth out small imperfections if that’s all you need. But if the concrete floor has low spots and needs to be smoothed even more, it can be poured as thick as an inch and a half without adding aggregate and 5 inches with the addition of aggregate (though make sure you follow all manufacturer’s guidelines).
Self-leveling concrete works especially well with radiant heating installations because it easily flows around the tubing. The thicker floor-leveling compounds that must be troweled to achieve a proper finish can’t do this.
If you find moisture is a problem in the slab, you need to get a professional to handle the moisture remediation. You can also visit the International Concrete Repair Institute (ICRI) for more information on next steps or to find an expert to help.
7 Tips on How to Apply Self-Leveling Concrete
- Read and follow the manufacturer’s instructions to the letter. Don’t skip or skimp on any step. And if any of these tips conflict with the instructions, go with the manufacturer’s process instead.
- Buy more products than you need. A difference of a fraction of an inch in thickness can mean several bags of product. You must finish the job in one pour so you can’t return to the store for more.
- Have all your tools and supplies ready. Once you pour, you may only have about 10-20 minutes to work.
- Keep your leveler product dry – store the bags indoors and up off the ground.
- Do not mix products in extremes of heat or cold.
- Do not add water to the product while spreading it. The mix ratio is critical.
- Clean all tools and buckets immediately when you’re done. If you allow the product to set it will never come off.
- Be careful not to pour more product than you need. If you do, quickly and carefully scoop it up into a bucket and remove it.
Where Self-Leveling Concrete Is Used
Let’s say you’re upgrading an old, damaged concrete floor that’s settled or cracked. Or maybe you’re installing a radiant heating system in a floor. Maybe you’re building an addition and must match the floor to the floor in an adjoining room. Maybe you’re finishing a basement where the floor is rough and uneven concrete.
Other concrete toppings applications include warehouse floors, light industrial applications, retail stores, and institutional facilities.
Concrete toppings can also receive pigmented color dyes, stains, saw cuts or mechanical polishing to produce a decorative concrete finished wear surface.
Cost of Self-Leveling Concrete
The cost of self-leveling concrete can vary depending on various factors such as the size of the area to be covered, the thickness required, and the brand of the product. On average, a 50-pound bag of self-leveling concrete costs between $30 to $60, and it typically covers an area of about 20 to 30 square feet at a quarter-inch thickness.
Keep in mind that this is only the cost of the material itself. If you’re hiring a professional for the job, labor costs will also factor in. The labor cost usually depends on the complexity of the job and the contractor’s experience and can range from $3 to $5 per square foot.
When compared to traditional concrete leveling methods, self-leveling concrete often proves to be more cost-effective due to its ease of application and reduced labor cost, although the initial material cost might be higher.
Preparing to Use Self-Leveling Compound
Before installing your new floor, there’s an essential consideration you need to address: moisture in the existing concrete floor. All concrete contains moisture, and if the moisture level is too high, it may cause the leveling compound to degrade over time.
So you need to test the slab to ensure the moisture level is not too high.
This isn’t something you can do just by looking at the slab. No matter how the slab looks, moisture deep in the slab can migrate to the surface over time and cause serious problems.
If the moisture level deep in the slab is too high, you need to take steps to remediate it before you can pour your new concrete floor.
RH testing is the basis for the ASTM F2170 standard. This standard governs the processes of obtaining results using in situ probes in concrete slabs. Despite the complex terminology, this test method is actually straightforward and much faster than you would think.
Once the L6 sensors are installed in the slab and equilibrated after the F2170 requirement of 24 hours, there’s no need to move them from location to location and wait for them to equilibrate again.
Repeat readings can be taken without additional equilibration time. And unlike reusable probes, the L6 sensors never need calibration.
- Shop vacuum, broom, and mop
- Mixing buckets or barrels, as large as you need (6-gallon minimum)
- Mixing drill and mixing head
- Gauge rake
- Kraft paper or plastic sheet
- Silicone caulk
- Leveling product and primer
Troubleshooting Self-Leveling Concrete
While self-leveling concrete is designed to be easy to use, problems can sometimes occur. Here are a few common issues and their solutions:
If the compound doesn’t level as expected, it might be due to incorrect mixing or application. Ensure that you follow the manufacturer’s instructions for mixing and applying the product. Using a gauge rake can help to distribute the product evenly.
Cracking or Curling
This can happen if the compound dries too quickly, which might be due to high temperatures or low humidity. Try to control the working environment as much as possible to avoid rapid drying.
Loose or Debonding Layers
This problem may occur if the old concrete surface wasn’t prepared properly before application. Make sure the surface is clean, free of dust or oil, and primed if necessary before applying the self-leveling concrete.
As mentioned in the original article, high moisture levels can cause problems. Always check the moisture content of the slab before application and take necessary steps if the moisture level is too high.
Remember, when facing difficulties, it’s always beneficial to reach out to a professional or contact the product manufacturer’s customer service. They can provide you with specific advice and guidance based on your situation.
Free Download – 4 Reasons Why Your Concrete Is Taking Forever to Dry
Takeaways for a Successful Self-Leveling Pour
Whenever you need to repair, level or raise a floor, self-leveling concrete can be a fast, cost-effective solution.
Self-leveling concrete can be used as an underlayment for tile, carpet, or other floor coverings.
For a successful self-leveling concrete installation, follow the seven tips in this article.
To ensure that your finished floor does not suffer from a concrete flooring failure, it’s essential to test the concrete subfloor for high moisture levels according to the ASTM F2170 standard. It’s not that hard to do, and you’ve got a great product from Wagner Meters that can help.
The Rapid RH L6 system is the fastest, easiest, most cost-effective system for RH testing concrete slabs in compliance with ASTM F2170. It will get you accurate results in a fraction of the time versus other methods, and it’s digital, with convenient wireless communication to your smart device.
Jason has 20+ years’ experience in sales and sales management in a spectrum of industries and has successfully launched a variety of products to the market, including the original Rapid RH® concrete moisture tests. He currently works with Wagner Meters as our Rapid RH® product sales manager.
Last updated on June 7th, 2023