How to Seal Concrete Floors With High Moisture Content

Basement floors get wet from humidity and from structural leaks.

Concrete floors require regular maintenance if you want them to last a long time while still looking their best. Sealing the floor makes it simpler to clean while also protecting the concrete against damage from water or impact. The sealer also prevents concrete dust from spreading throughout a room, and it fills the pores in the concrete so moisture won't come up from underneath the slab. If the concrete floor is moist due to high humidity or recent water exposure, dry it as thoroughly as possible before you seal it.

Things You'll Need

• Dehumidifier
• Dish soap or mild detergent
• Towel
• Fans
• Rust removal agent
• Scrub brush
• Mop with mop bucket
• Concrete floor sealer

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Instructions

1. Identify the source of the moisture buildup. Any leaks that are affecting the floor require repair before you can move forward. High humidity should be countered with a dehumidifier while you are working to prevent water from getting under the sealer as you apply it.

2. Wash the floor with warm water and a mild detergent. Several drops of liquid dish soap are useful for this because dish soap is gentle while also working as an antidirt and antigrease agent. Dry the floor thoroughly by either running a towel over it and allowing it to air-dry or by placing fans on it to accelerate the process.

3. Remove any rust stains from the concrete, using a rust removal agent. Scrub it into the stains with a scrub brush and then rinse it once the stains are removed. Any stains that are on the concrete will become locked in there once you seal the floor, so it's best to get the floor as clean and stain-free as possible.

4. Use a mop to apply sealer to the floor once it is fully clean and dry. Start in a far corner of the room and work backward toward the door so you don't have to walk across the sealer, which is both very slippery and likely to retain footprints.

5. Apply a second coat once the first coat is dry. Some sealers recommend waiting a week before applying the second coat, while others allow you to do it within a few hours. Follow all instructions on the container for the best results.

Tips & Warnings

• Wax the floor once the two coats of sealer have fully dried for additional shine and moisture protection. Three coats of wax on two coats of sealer typically provide the best results and a long-lasting moisture barrier.

References

• Concrete Network.com: How to Seal Plain Concrete
• Iowa State University: Controlling Moisture on Concrete Floors