Tar Paper Under Laminate Flooring: Pros, Cons, and Best Alternatives

Using tar paper, an asphalt-saturated felt, as underlayment for laminate flooring is a topic that surfaces in DIY guides and contractor notes. This article examines whether tar paper can be used under laminate, why it’s generally discouraged, and what better options exist to protect against moisture, reduce sound, and improve comfort. Readers will find actionable guidance for common subfloors in the United States, including wood, plywood, and concrete, with practical steps to ensure a durable, gap-free installation.

What Is Tar Paper And How Does It Work

Tar paper, also known as asphalt-saturated felt, is a traditional moisture barrier used in roofing and some floor installations. Its primary purpose is to repel water from above and prevent moisture from seeping into structural materials. When used under laminate, tar paper can act as a barrier between the subfloor and the laminate’s underlayment. However, laminate flooring requires a specific balance of moisture control, sound reduction, and a flat, stable surface. Tar paper can compromise one or more of these needs if not installed properly. Key point to remember: tar paper is not designed to meet modern lamination underlayment standards, which emphasize uniform thickness, vapor management, and surface stability.

Why Tar Paper Is Generally Not Recommended for Laminate

There are several reasons why tar paper is not the preferred choice for laminate installations in most U.S. homes. First, lamination responds best to underlayment that provides a consistent, cushioned surface; tar paper can have irregularities that telegraph through the laminate, causing warmth or sound issues. Second, tar paper can trap moisture if the subfloor has any residual dampness, especially on concrete slabs, potentially leading to mold risk or adhesive failure. Third, tar paper is less effective for sound dampening compared with purpose-built underlayments designed for laminate. Finally, tar paper is less forgiving of minor subfloor imperfections, which can result in visible seams or chatter underfoot. Practical takeaway: if a moisture barrier is needed, use products specifically rated for laminate installations, not generic tar paper.

Moisture Management Across Subfloors

Effective moisture management starts with identifying the subfloor type. On wooden subfloors, moisture risk is primarily from the environment rather than the subfloor itself, but concrete slabs require robust vapor barriers. For concrete slabs, a polyethylene vapor barrier or a specialized underlayment with a built-in moisture barrier is often recommended. Wood subfloors should be checked for dry conditions and leveled before any underlayment is installed. In climates with high humidity or basements, a breathable, foam-based or cork underlayment with a dedicated vapor barrier can offer both moisture control and acoustic benefits. Rule of thumb: never rely on tar paper alone to meet modern moisture standards for laminate floors.

Better Alternatives To Tar Paper

Numerous underlayment options are better suited for laminate flooring than tar paper. The choice depends on subfloor type, room conditions, and desired benefits such as sound reduction or warmth. Below are common, well-regarded alternatives:

• Foam Underlayment: An inexpensive, easy-to-install option that provides a smooth surface and basic sound reduction. Choose a product with a built-in moisture barrier for concrete slabs.
• Butyl or Polyethylene Vapor Barriers: In concrete installations, a separate vapor barrier under a high-density underlayment helps limit moisture migration.
• Rosin Paper (Builder’s Paper): A lightweight, breathable paper sometimes used under wood floors, but it is less common under laminate unless specified by the manufacturer.
• Wood Fiber or Cork Underlayments: These materials offer superior sound insulation and comfortable underfoot feel while maintaining moisture control when paired with appropriate barriers.
• Hybrid Underlayments: Combine moisture barriers with sound-dampening layers and are engineered specifically for laminate installations.

Guidelines For Selecting Underlayment

When choosing underlayment for laminate flooring, consider the following factors. Compatibility: Always verify the underlayment is rated by the laminate manufacturer. Moisture Barrier: Select a product with a moisture barrier if installing over concrete or in damp basements. Sound Reduction: If noise is a concern, look for products with higher ANSI or AC ratings for impact sound reduction. Flatness: Ensure the subfloor is flat to within manufacturer tolerances to prevent telegraphing. Climate: In extreme temperature ranges, underlayment with thermal properties can improve comfort. Installation: Follow precise installation guidelines, including seams alignment and expansion gaps.

Step-By-Step Installation Guidance

Below is a practical workflow for laminate installation that avoids tar paper and uses a recommended underlayment. This approach supports a durable, visually appealing floor.

1. Prepare Subfloor: Clean, dry, and level the surface. Repair any cracks or high spots; allow subfloor to acclimate to room conditions.
2. Check Humidity: For wood subfloors, ensure moisture levels meet the laminate manufacturer’s requirements. For concrete, confirm the slab’s moisture content and install an appropriate vapor barrier.
3. Lay Underlayment: Install the chosen underlayment with the vapor barrier facing the subfloor (as specified by the product). Seal seams according to manufacturer instructions.
4. Acclimate Laminate: Allow planks to acclimate in the room for the recommended duration before installation to reduce shrinkage or expansion post-installation.
5. Install Flooring: Follow the click-lock or glue-down method recommended by the laminate brand. Leave expansion gaps around the perimeter and at fixed objects.
6. Finish: Install baseboards or trim to cover expansion gaps. Clean the surface to remove any dust or packaging residues.

Common Mistakes To Avoid

Avoid These Pitfalls To Protect Your Investment. Overlapping tar paper or using it as the sole moisture barrier can trap moisture and damage the floor. Skipping acclimation or using a non-rated underlayment may lead to warping, edge lifting, or squeaks. Neglecting subfloor irregularities can telegraph through the laminate. Lastly, mismatching underlayment thickness with the door clearances can create installation problems in tight spaces.

FAQs

Can I use tar paper under laminate flooring? Generally not recommended in modern installations. Tar paper can trap moisture, fail to provide adequate flatness, and not meet manufacturer specifications. Use a purpose-built underlayment with a dedicated moisture barrier when needed.

What underlayment should I use over a concrete slab? Use a high-quality laminate underlayment with a built-in vapor barrier or install a separate vapor barrier beneath the underlayment to control moisture.

Is rosin paper acceptable under laminate? Rosin paper can be used in some cases, but always check the laminate manufacturer’s recommendations. It often provides minimal moisture protection compared with modern underlayments.