Is Pre-Attached or Separate Underlayment Laminate Flooring Best?

New Floor Installation
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Unlike floors that have a high degree of tolerance for problems such as moisture and wear, laminate flooring works only as long as you take proper precautions.

Tightly seaming the boards against moisture is one such precaution. Another precaution is installing underlayment below the planks.

Pre-Attached vs. Separate Underlayment

Laminate flooring manufacturers always recommend having an underlayment under the boards. Underlayment can help to smooth over small imperfections in the subfloor (substrate); provide minor sound absorption; and soften footfall. 

Underlayment is found in two forms:

  • Separate: Rolls of 3 mm polyethylene foam or felt underlayment laid on the subfloor prior to installation and taped side-to-side.
  • Attached: Underlayment may be pre-attached by the manufacturer to the bottom of the laminate planks. Not only does this eliminate the preliminary step of rolling out underlayment, you are prevented from using separate underlayment--the flooring would not lay correctly.

Bottom Line

Laminate manufacturers are slowly going the way of producing more planks with pre-attached underlayment than planks that require separate underlayment. Even so, buying laminate flooring with separate underlayment is your best option at this time.

One reason is that separate underlayment gives you better control. If sound is a problem, you could pair 12 mm thick laminate with heavy felt underlayment for a high quality, though expensive, laminate floor. If smoothing out the substrate is your only aim, you could purchase closed cell polyethylene underlayment for a less expensive flooring product.

Separate Underlayment

  • Inexpensive: Polyethylene foam underlayment, the cheapest you can purchase, costs as little as $0.15 per square foot.
  • Improves Thin Laminate: Buying cheap laminate floor means that you are also buying thin laminate. Boards under 8 mm qualify as thin. Lumber Liquidators sells the cheapest, thinnest laminate around: 2 mm. To put that in perspective, two U.S. dimes are thicker than 2 mm. With such paper-thin product, underlayment is not just a good idea, it is mandatory.
  • Control: You can choose your underlayment and not have it chosen for you, which helps control the overall cost and quality of floor installation.

Brands With Unattached Padding

At one time, nearly all laminate required separate underlayment. These are now becoming more difficult to find. A few brands and lines that do not have attached underlayment are:

  • Pergo Portfolio
  • Shaw laminates without the suffix "Plus"
  • Many Lumber Liquidators Dream Home laminates
  • Lowe's Style Selections brand
  • Home Depot's Trafficmaster brand
  • Most laminates under 10 mm thick

Types and Brands of Underlayment

Foam: Foam underlayment is cheaper than felt underlayment. Lighter foam does little more than smooth out the substrate; it has practically no sound absorbing qualities. Heavier, denser foam is better at limiting the transmission of sound but not by much.

Felt: Felt underlayment tends to be over four times heavier than foam and at least twice as expensive. This recycled product carries higher sound absorption ratings than other underlayment types.

Pre-Attached Underlayment

  • Saves Time, But Not Much: Eliminating one step from the process of installing flooring may reduce overall time spent on the project. Note that it usually takes little time to lay out and tape separate underlayment. Budget about thirty minutes to install underlayment in a 400 square foot room.
  • Pre-Attached Is Thinner Underlayment: Pre-attached underlayment tends to be 2 mm. Separate underlayment is slightly thicker, at 3 mm.
  • Gaps in Underlayment: Every board has its own underlayment, which means that you have a floor of hundreds of separate underlayment pads with seams separating them.

Brands With Attached Padding

Laminate companies are slowly filling their catalogs with more attached-pad flooring. For example, laminate floor originator Pergo now has a catalog with pre-attached pads on over 75% of its products.

  • Lumber Liquidators Dream Home and Dream Home XD, mostly confined to the 10 mm and 12 mm thicknesses.
  • Pergo XP, Pergo Max, Pergo Outlast+.
  • Lowe's Allen + Roth.
  • Shaw laminates with the suffix "Plus." For example, Shaw Biltmore Plus.