Laminate Flooring Installation Over a Concrete Subfloor—Requirements and Preparation

If you’re installing your laminate flooring in a basement, or ground floor, it’s likely you’ll run into a concrete subfloor. As a sturdy foundation, a concrete subfloor is a great surface to lay a laminate floor on. Since concrete is a porous material, there are a few requirements to prepare a concrete subfloor before installing your laminate flooring.

#1. Take a Moisture Rating

The moisture factor with a concrete subfloor is the most important thing to consider. The moisture reading for concrete subfloors cannot be higher than 4.5%. Concrete can often times hold moisture for longer than other types of floors due to its’ porous composition. If you poured your subfloor recently, make sure you get an accurate reading on the moisture level prior to installation. As a rule, new concrete must cure for 60 days before you can install laminate, vinyl or hardwood flooring on top.

To check your moisture levels by using a standard moisture meter. You can also use the Calcium Chloride Test. Even if your concrete subfloors are a few years old, it is still important to check the moisture levels. There could be unsuspecting areas of moisture you were not aware of.

#2. Check Levelness 

When installing laminate flooring over concrete, it is also important to inspect the levelness and surface. Since laminate is a floating floor installation, areas of peaks and lows can interfere with the stability of the locking system and joints.

Any subfloor should be free of major gaps, voids, or crevices. If you find that your concrete subfloor has cracks or crevices, you will need to repair the subfloor using a cement compounding agent. If there is too much variation in the levelness, anything greater than 3/16 inches in a 10 foot radius, you must either level low spots with a cement and latex compounding agent or ground low spots.

#3. Use a Vapor Barrier Underlayment

As mentioned, concrete subfloors are porous and have the potential to hold onto excess moisture. It is important to choose an underlayment with a vapor barrier for all laminate flooring installations on concrete subfloors. If you want to learn more about the right underlayment for your laminate flooring installation, click here.

If your laminate flooring has an underlayment attached, you should use a vapor barrier film to protect your floors.

For hardwood floors, you can opt for a floor muffler or Aquabar underlayment. Glue down hardwoods do not require any underlayment.

#4. Floor Drains and Pipes

Never install your flooring over a concrete subfloor with a drain. If the water gets backed up you might not see the flood or problem until it is too late.

Likewise, you should not install your flooring over a sump pump.

Once your concrete subfloors are checked and approved, you’re ready to begin your installation!

Have a few lingering questions? Let’s chat! Contact our flooring experts for more help determining the condition of your subfloor.

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