Flooring Underlayment Basics: What to Know Before You Buy

Installing new flooring can completely transform the look and feel of a room. But the quality of your floor installation depends heavily on the underlayment. Choosing the right underlayment is crucial for providing a smooth, quiet, and well-protected foundation for your new flooring. This comprehensive guide will walk you through the basics of flooring underlayments to help you select the perfect product for your project.

What is Flooring Underlayment?

Flooring underlayment is a thin layer of material installed underneath flooring to provide a smooth, uniform surface. Underlayment panels are typically 1/4″ to 1/2″ thick. The underlayment creates a protective barrier between your subfloor and finished floor to prevent moisture damage, smooth out imperfections, insulate against sound transmission, and improve comfort underfoot.

There are several different types of underlayment materials:

  • Felt – Compressed paper fiber, economical option for laminate and vinyl plank flooring
  • Cork – Natural material made from cork oak tree bark, provides cushioning
  • Rubber – Provides excellent sound dampening, often used under hard surface flooring
  • Foam – Closed or open cell foam, adds comfort and insulation
  • Plywood – Sturdy wood panels create smooth surface for flooring

Choosing the right underlayment will depend on your subfloor type, chosen flooring, and performance needs. Keep reading to learn more about selecting the best underlayment for your home.

Reasons to Use Flooring Underlayment

There are several important benefits that a quality underlayment provides:

Smooths Out Subfloor Irregularities

Underlayment creates an even, uniform surface over an existing subfloor. This compensates for any slight depressions, bumps, cracking, or uneven areas in the subfloor. Smoothing out these imperfections helps prevent them from telegraphing through the finished floor and negatively impacting the look and performance.

Adds Comfort Underfoot

Certain underlayment materials like cork and rubber provide a slight cushioning effect. This increases comfort, especially for floors installed over concrete subfloors. Underlayments with insulation properties can also help a floor feel warmer.

Reduces Noise

Quality underlayments will dampen the transmission of noise between floors. This provides important soundproofing, especially for upper level units in multi-family buildings. Underlayment helps block noise transfer for quieter, more peaceful rooms.

Protects Against Moisture

Flooring underlayments provide an impermeable moisture barrier between the subfloor and flooring. This prevents spills, flooding, or ground moisture from seeping through the flooring and causing damage. Proper moisture protection preserves the life of the flooring.

Extends Service Life of Flooring

By smoothing irregularities, adding cushioning, preventing moisture damage, and reducing wear from noise vibrations, underlayments help protect flooring materials. This extended service life repays the small initial investment in underlayment many times over.

Factors to Consider When Selecting Underlayment

With an understanding of the benefits, we can now explore the factors that help determine the best underlayment choice:

Type of Subfloor

The existing subfloor influences underlayment selection. For concrete subfloors, foam or cork provide better insulation and comfort. For wood subfloors, felt and rubber are common options. Manufacturers may indicate suitable subfloor types.

Choice of Flooring

Laminate and engineered wood floors need underlayments with moisture barriers. Natural stone and tile require cushioning help. Always check flooring specifications for underlayment recommendations.

Location and Use

High traffic areas benefit from underlayment with extra durability and indentation resistance. Upstairs rooms need options with maximum soundproofing. Wet areas require exceptional moisture barriers.

Installation Method

Glue-down floors require thin, dense underlayments. Floating click-lock floors pair well with thicker, cushier materials. Ensure underlayment and flooring installation methods are compatible.

Cost Considerations

Felt and foam are generally the most budget-friendly options. Rubber and cork provide excellent performance at moderate cost. Plywood is the most expensive choice. Prioritize key benefits over cost alone.

Environmental Factors

Look for sustainable underlayment materials like organic felt, natural cork and rubber. Check certifications. Avoid old carpet padding which may contain harmful substances.

Considering these factors will guide you towards the ideal underlayment for your specific subfloor, flooring, room usage, and budget.

Types of Flooring Underlayment

Now let’s take a closer look at the pros, cons, and appropriate uses for the most common floor underlayment materials:


Felt underlayment consists of tightly compressed paper fibers. It is one of the thinner, more affordable underlayment options.

Key Features:

  • Economical price point
  • Thin profile from 1/8″ up to 1/4″ thickness
  • Easy for DIY installation
  • Made from recycled materials
  • Can act as moisture barrier when coated

Best Uses:

  • Laminate flooring
  • Vinyl plank flooring
  • Areas with light to moderate traffic
  • Dry areas only unless moisture membrane coated


  • Minimal sound insulation
  • Not for use over concrete subfloors
  • Durability limits for high traffic areas
  • Requires additional moisture barrier in damp areas


Cork underlayments provide natural soundproofing and comfort. Cork is harvested from the bark of cork oak trees without harming the tree.

Key Features:

  • Naturally moisture resistant
  • Good acoustic insulation up to 70 dB
  • Comfortable cushioning effect
  • Hypoallergenic and antimicrobial
  • Sustainable and recyclable

Best Uses:

  • Hardwood, laminate, and vinyl floors
  • Tile and stone flooring
  • Basements and condos with noise concerns
  • Concrete subfloors to increase comfort


  • More expensive than felt or foam
  • Thicker than some options at up to 1/4″
  • Not for extremely damp or wet areas


Rubber underlayments excel at sound absorption and durability. Reclaimed rubber or tire crumb rubber are common materials.

Key Features:

  • Excellent impact sound insulation
  • Withstands heavy foot traffic
  • Made from recycled rubber in sustainable versions
  • Does not deteriorate or compress over time
  • Available in rolls for easy installation

Best Uses:

  • Hardwood, laminate in high traffic areas
  • Multifamily housing with noise concerns
  • Basements and concrete subfloors
  • Commercial and industrial flooring


  • Can have lingering rubber odor
  • Higher cost than felt or foam
  • Thicker profile up to 1/4″ may raise floor


Foam underlayments like rebond pad provide affordable sound dampening. Available as dense closed-cell or cushy open-cell.

Key Features:

  • Good sound insulation, 60-70 dB for floors
  • Cushioning for hard surfaces like concrete
  • Allows for floating floor movement
  • Variety of thicknesses from 1/8″ to 3/8″
  • Low cost material

Best Uses:

  • Laminate and vinyl plank floors
  • Hardwood flooring
  • Basements, condos, apartments
  • Radiant heating floor systems


  • Durability limits for high-traffic areas
  • Minimal moisture protection on its own
  • Can compress or deteriorate over time
  • Not for extremely damp areas


Plywood offers an extremely smooth, stable underlayment surface. Often made from birch wood.

Key Features:

  • Provides flawless flat surface
  • Stability resists dips and indentation
  • Excellent load-bearing strength
  • Available in many thicknesses
  • Can be sanded smooth

Best Uses:

  • Natural hardwood flooring
  • Solid wood subfloors
  • Commercial and industrial installs
  • Renovation over damaged subfloors


  • More expensive option
  • Special tools needed to install properly
  • Heavy and difficult to cut
  • Lacks moisture barrier

Best Underlayment Options by Flooring Type

We’ve covered the basics of the main underlayment categories. Here are more specific recommendations for optimal underlayment selection based on your chosen flooring:

Hardwood Flooring Underlayment

For solid and engineered hardwood floors, look for underlayments that cushion without excessive compression or movement. Plywood and cork are excellent choices. Felt or rubber can also work if not too thin. Ensure moisture barrier protection.

Laminate Flooring Underlayment

Laminate flooring pairs well with foam, felt, or cork underlayments in the 1/8” thickness range. Prioritize options with attached moisture barrier films. Avoid soft, spongy materials that allow too much floor movement.

Vinyl Plank Underlayment

Vinyl plank flooring requires a thin, dense underlayment like rebond foam or recycled felt. Limit underlayment thickness to 1/8” or risk compromising the vinyl plank locking system. Focus on sound insulation.

Tile or Stone Underlayment

Tile needs a crack isolation membrane topped with a cement board underlayment. For a more cushioned surface, add a thin foam layer before the membrane. This enhances comfort on harder surfaces.

Concrete Subfloor Underlayment

For cold, hard concrete subfloors invest in a quality foam, cork, or rubber underlayment. This adds warmth and comfort while smoothing any variations in the slab. Most concrete subfloors benefit from vapor barrier protection.

Tips for Installing Underlayment

Underlayment plays a critical role in flooring performance, so take care to install it properly:

  • Always follow manufacturer’s installation guidelines
  • Unroll underlayment and allow time to relax before installing flooring over top
  • Butt edges together tightly without overlapping
  • Use an adhesive seam tape to join any seams or edges
  • Run the underlayment up walls about 1” to provide a full moisture barrier
  • Carefully cut around pipes, drains, pillars and other fixtures
  • Fill any seams or gaps with adhesive caulk to prevent moisture intrusion

Investing a small amount of extra time during underlayment installation prevents major headaches down the road.

Frequently Asked Questions

Still have questions about choosing and installing the right flooring underlayment? Here are answers to some of the most common questions:

Do I need underlayment for vinyl plank flooring?

Yes, vinyl plank flooring requires underlayment for proper installation and performance. Choose a very thin, dense underlayment no thicker than 1/8”. This prevents an uneven floor surface. Look for vinyl plank underlayments with attached vapor barriers.

What kind of underlayment should I use for laminate floors?

For laminate flooring, use a thin foam, felt or cork underlayment in the 1/8” thickness range. Ensure the underlayment allows the laminate floor to float freely rather than compressing too much. An attached moisture barrier film is recommended.

Can you install hardwood floors over concrete without underlayment?

It is not recommended to install hardwood flooring directly over concrete. A proper underlayment is vital to provide moisture protection, smooth any variations, and add insulation against the cold slab. Cork or rubber are great choices for concrete subfloor underlayments.

Should underlayment go under or over vapour barrier?

The vapor barrier should be installed directly over the subfloor, then the underlayment placed over the vapor barrier. The plastic moisture barrier protects from ground moisture, while the underlayment provides cushioning. Follow flooring manufacturer instructions.

What thickness of underlayment is best?

In general, a thinner underlayment from 1/8” up to 1/4″ is preferable. Thinner underlayments are suitable for floating floors and prevent an uneven floor surface. Use thicker underlayment only if recommended for the specific flooring type per the manufacturer.

Can I install underlayment and flooring in sections rather than all at once?

It is strongly recommended to install the underlayment and flooring across the entire room for best results. But for DIY projects in a single large space, you can do sections if necessary. Allow the flooring to run 6” past the underlayment end to properly join the sections.


Choosing the ideal underlayment involves considering your subfloor, flooring type, usage, and noise or moisture needs. Felt, foam, cork, rubber, and plywood each provide different benefits. Following manufacturer guidelines and proper installation techniques ensures your underlayment performs as intended. Investing in quality underlayment provides a smooth foundation that enhances the durability and enjoyment of your new flooring.