How to Install Laminate Flooring on Cement

How to install laminate flooring on cement

To install laminate flooring on cement, thoroughly prepare the concrete subfloor by cleaning, leveling, and testing for moisture. Properly lay a 6-mil vapor barrier and underlayment. Then, click the laminate planks together following manufacturer guidelines, ensuring expansion gaps are maintained around the entire perimeter of the room.

Installing laminate flooring over a concrete slab is a common and achievable DIY project. Concrete is a stable subfloor, but it requires specific preparation to ensure your laminate lasts. You’ll need to address moisture, ensure the surface is level, and use the correct underlayment.

Before you begin, gather your tools and materials. You’ll need the laminate flooring planks, underlayment (often a combination vapor barrier and sound reducer), a vapor barrier if not integrated into the underlayment, a tape measure, a utility knife, a tapping block, a pull bar, a rubber mallet, a jigsaw or miter saw for cuts, safety glasses, a dust mask, and potentially a moisture meter and leveling compound.

Start by clearing the room of all furniture and removing existing flooring, baseboards, and quarter-round trim. Inspect the concrete slab carefully. It must be clean, dry, and free of cracks or significant imperfections. Sweep and vacuum thoroughly to remove all dust and debris. A clean surface is crucial for adhesion and a smooth finish.

Check for moisture. Concrete slabs, especially those on or below grade, can emit moisture that will damage laminate. Use a reliable moisture meter or perform a simple plastic sheet test. Tape a 3-foot by 3-foot piece of plastic sheeting tightly to the concrete. After 24 hours, check for condensation on the underside of the plastic or any dampness on the concrete. If moisture is present, you must address it, often with a specialized moisture-blocking primer or a thicker vapor barrier, before proceeding.

Prepare the concrete subfloor

The concrete must be level. Most laminate manufacturers require the subfloor to be flat within 3/16 inch over a 10-foot span. Use a long, straight edge or a level to check for high and low spots. For high spots, you can carefully grind them down with a concrete grinder. For low spots, use a self-leveling compound designed for concrete floors. Follow the product instructions precisely for mixing and application, and allow it to cure completely.

Ensure the concrete is free of any old adhesive, paint, or sealers that could prevent proper underlayment or plank locking. A scraper or grinder may be necessary. The goal is a smooth, monolithic surface. If you have radiant heating in your slab, ensure your laminate and underlayment are compatible with it, and follow specific installation guidelines for heated floors.

Install the underlayment and vapor barrier

Laminate flooring requires an underlayment for cushioning, sound reduction, and to provide a smooth surface. For concrete subfloors, it’s highly recommended, and often mandatory, to use an underlayment that includes a built-in vapor barrier or to install a separate 6-mil polyethylene vapor barrier. This protects the laminate from moisture seeping up through the concrete.

If using a separate vapor barrier, unroll the 6-mil polyethylene sheeting over the entire concrete surface, overlapping seams by at least 6 inches. Tape the seams securely with a strong, waterproof tape. Run the sheeting up the walls about 2-3 inches. Trim excess later. This creates a continuous moisture barrier.

Next, lay down your laminate underlayment according to the manufacturer’s instructions. This might be a foam roll, felt, or cork material. If it doesn’t have an integrated vapor barrier, ensure your separate vapor barrier is installed first. Roll out the underlayment perpendicular to the direction you plan to lay your laminate planks. Overlap seams as recommended by the manufacturer, and tape them if necessary. Ensure the underlayment covers the entire area where the laminate will be installed.

Lay the laminate planks

Begin installing the laminate planks in the longest, straightest run of the room, usually starting along an exterior wall. Leave an expansion gap of about 1/4 to 3/8 inch around the perimeter of the room, including against walls, doorways, and any fixed objects like cabinets or pipes. This gap is crucial to allow the laminate to expand and contract with changes in temperature and humidity without buckling.

Use spacers between the planks and the walls to maintain this gap. Most laminate flooring uses a click-lock or tongue-and-groove system. Start the first row by connecting the short ends of the planks. For subsequent planks in the first row, you may need to cut off the tongue on the side that will face the wall. You can use a utility knife for this.

Continue laying planks, connecting them end-to-end and side-to-side. Use a tapping block and rubber mallet to gently tap the planks into place, ensuring a tight fit without damaging the edges. For the last plank in a row, you’ll likely need to cut it to length. Measure the remaining space, subtract your expansion gap, and cut the plank. Use a pull bar to engage the end joint.

Begin the second row with the offcut from the first row, ensuring it’s at least 6 inches shorter than the first plank in the previous row to create a staggered or offset pattern. This interlocking pattern provides structural integrity and a more natural wood appearance. Continue this process, staggering the end joints by at least 6 inches in each row for strength and aesthetics. Use your jigsaw to cut intricate shapes around doorways, vents, or other obstacles, always remembering to maintain the expansion gap.

Finishing touches

Once all planks are laid, trim the excess vapor barrier and underlayment along the walls. Reinstall your baseboards and quarter-round trim. The baseboards should cover the expansion gap. Ensure the baseboards are secured to the wall, not to the laminate flooring, so they don’t restrict the floor’s movement.

If you have transitions to other flooring types, install transition strips (such as T-molding, reducers, or end caps) in doorways or where the laminate meets another floor. These are typically screwed or glued down to the subfloor, not the laminate.

Clean the new floor according to the laminate manufacturer’s recommendations. Avoid excessive water, as it can damage the material. Sweep or vacuum regularly and use a damp mop with a laminate-specific cleaner for deeper cleaning.

Common mistakes when installing laminate on cement

FAQ

Do I need a vapor barrier when installing laminate on cement?

Yes, a vapor barrier is almost always required when installing laminate flooring over a cement subfloor, especially on ground level or below. Concrete can emit moisture, which can damage the laminate’s core and backing. Use at least a 6-mil polyethylene vapor barrier, or an underlayment with an integrated vapor barrier.

Can I install laminate flooring directly over old vinyl or tile on cement?

Generally, no. You must remove existing flooring to expose the concrete subfloor. The concrete needs to be clean, level, and dry. Installing over existing flooring can lead to an uneven surface, improper locking of the laminate, and potential moisture issues trapped underneath.

How do I cut laminate flooring for doorways?

You’ll need to undercut the door casings. Place a piece of laminate and the underlayment next to the casing and mark the height you need to cut. Use a hand saw or oscillating multi-tool to cut the bottom of the casing, allowing the laminate to slide underneath while maintaining the necessary expansion gap.

What kind of underlayment is best for laminate on concrete?

For concrete subfloors, choose an underlayment that includes a built-in vapor barrier or use a separate 6-mil polyethylene vapor barrier. The underlayment itself should provide cushioning and sound dampening. Check the laminate manufacturer’s specific recommendations for underlayment compatibility.