How to install laminate flooring underlayment
Install laminate flooring underlayment by rolling it out over the subfloor, ensuring seams overlap correctly and are taped. Cut to fit around obstacles and against walls. It provides cushioning, sound dampening, and a moisture barrier, essential for laminate’s longevity.
Before you begin installing laminate flooring, preparing the subfloor and laying the underlayment is a critical step. Underlayment provides a moisture barrier, sound insulation, and cushioning for your new floor. You’ll typically find underlayment in rolls, either made of foam, felt, or a combination.
Start by ensuring your subfloor is clean, dry, and level. Remove any debris, staples, or old adhesive. If you’re installing over concrete, a vapor barrier underlayment is essential. For wood subfloors in basements or over crawl spaces, a vapor barrier is also highly recommended. Many laminate underlayments come with a built-in vapor barrier, often indicated by a plastic film on one side. If yours does not, you’ll need to install a separate vapor barrier first, typically a 6-mil polyethylene sheeting, overlapping seams by 6-12 inches and taping them with construction tape.
Begin unrolling the underlayment perpendicular to the direction you plan to lay your laminate planks. Leave a small gap around the perimeter of the room, similar to how you’ll leave a gap for the laminate itself. This allows for expansion and contraction.
Butt the seams of the underlayment together. Do not overlap them unless the manufacturer specifically instructs you to do so. If they have a self-adhering strip, use it. Otherwise, use a good quality seam tape specifically designed for underlayment to join the sections. This tape prevents the seams from separating and maintains the integrity of the underlayment layer.
Trim the underlayment with a utility knife to fit around doorways, cabinets, and other fixed obstacles. You can score and snap thicker foam underlayment, or simply cut through thinner foam or felt. Ensure the underlayment lies flat and smooth, without any wrinkles or bubbles, as these can transfer to the finished laminate floor.
When you reach a wall, cut the underlayment cleanly. Some installers recommend running the underlayment up the wall slightly, like a cove base, to ensure a complete seal. However, most manufacturers prefer it to be cut flush with the wall, especially if you’re using a separate vapor barrier that is taped to the wall.
Benefits of installing laminate underlayment
Installing laminate underlayment is not an optional step; it’s a requirement for most laminate flooring manufacturers and provides significant benefits. The primary function is to act as a sound dampener. Laminate can be noisy when walked on, producing a hollow or clicking sound. Underlayment absorbs much of this impact sound, making your home quieter and more pleasant.
Another crucial benefit is its role as a moisture barrier, particularly important for laminate installed over concrete slabs or in basements. Laminate flooring itself is not waterproof and can be damaged by moisture seeping up from below. A quality underlayment with a built-in or separate vapor barrier prevents this moisture from reaching the laminate, thus avoiding warping, buckling, or mold growth.
Underlayment also adds a layer of cushioning beneath your feet, making the floor feel more comfortable to walk on. This can reduce fatigue and make rooms feel more luxurious. Finally, it helps to smooth out minor imperfections in the subfloor. While significant subfloor issues need to be addressed, a good underlayment can compensate for very small irregularities, ensuring a flatter finished surface.
Types of laminate flooring underlayment
Underlayment for laminate flooring comes in several types, each with its own advantages. The most common are foam, felt, and rubber. Foam underlayment is lightweight, inexpensive, and offers good cushioning and moisture resistance, especially if it has a built-in vapor barrier. It’s easy to cut and install.
Felt underlayment is generally denser and provides better sound insulation than basic foam. It’s a good option for reducing footfall noise. Some felt underlayments also offer good moisture resistance.
Rubber underlayment is the densest and offers the best sound dampening and cushioning. It’s often used in high-traffic areas or where maximum sound reduction is desired. However, it can be more expensive and heavier than foam or felt. Some rubber underlayments also incorporate a moisture barrier.
Many underlayments are combination products, such as foam with a built-in vapor barrier or a felt with a plastic film. Always check the product specifications to ensure it meets your needs for moisture protection, sound reduction, and cushioning. Some manufacturers also offer specialized underlayments for radiant heated floors, which require specific thermal properties.
Preparing the subfloor for underlayment
Before you can lay down underlayment, the subfloor must be meticulously prepared. This step is non-negotiable and directly impacts the longevity and appearance of your laminate floor. Begin by sweeping or vacuuming the entire subfloor thoroughly. Remove all dust, dirt, and debris. Any small particles left behind can cause lumps or tears in the underlayment and eventually the flooring above.
Inspect the subfloor for any damage. This includes loose boards, protruding nails or staples, or significant cracks. Loose boards should be secured with screws. Protruding fasteners must be hammered down or removed. Fill any holes or cracks with a suitable patching compound and allow it to dry completely.
Check for levelness. Most laminate flooring manufacturers recommend a subfloor that is flat within 1/8 inch over a 6-foot span. Use a long level or a straightedge to check for high spots or low spots. High spots can be ground down, while low spots need to be filled with a leveling compound. Uneven subfloors can cause stress on the laminate planks, leading to joint failure and squeaking.
If installing over concrete, ensure it is completely dry. Moisture testing may be necessary. For basements or rooms above unconditioned spaces, a vapor barrier is essential, even if the concrete appears dry. If your chosen underlayment doesn’t have a built-in vapor barrier, you’ll need to install a separate one before laying the underlayment.
Common Mistakes When Installing Laminate Underlayment
| Step/Tool | Typical Mistake | Why It’s a Problem |
|---|---|---|
| Rolling out underlayment | Overlapping seams | Creates an uneven surface that can telegraph through the laminate, causing joint stress and potential buckling. It can also create a weak spot. |
| Taping seams | Using the wrong tape or not taping securely | Seams can separate, compromising the integrity of the underlayment layer, its moisture barrier capabilities, and its ability to provide a smooth surface. |
| Cutting underlayment | Leaving gaps or not cutting precisely around obstacles | Gaps allow moisture to reach the subfloor or air pockets to form. Imprecise cuts can lead to buckling or difficult transitions at walls and doorways. |
FAQ
How to install underlay for laminate flooring?
Roll out the underlayment perpendicular to your laminate planks, ensuring seams are butted together and taped securely. Cut it to fit around obstacles and trim it flush with the walls, leaving a small expansion gap around the perimeter. Ensure it lies flat without wrinkles.
Do I need underlayment for laminate flooring?
Yes, underlayment is essential for laminate flooring. It provides sound dampening, cushioning for comfort, and often includes a vital moisture barrier to protect the laminate from subfloor moisture, preventing damage and ensuring longevity.
What is the purpose of laminate flooring underlayment?
The primary purposes of laminate flooring underlayment are to provide sound insulation, reduce impact noise, add cushioning for comfort underfoot, and act as a moisture barrier to protect the laminate from subfloor moisture. It also helps to smooth minor subfloor imperfections.