Buckled laminate flooring after flooding Best Practices Guide to Engineered Wood Floors
Selection & Installation of Engineered & Laminated Wood Flooring

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Engineered wood floors & laminated wood floors:

This article explains the choices and proper installation of engineered wood flooring and laminated wood floor products.

This article series discusses and provides a best construction practices guide to the selection and installation of building interior surface materials, carpeting, doors, drywall, trim, flooring, lighting, plaster, materials, finishes, and sound control materials.

Our page top photo illustrates what can happen to an engineered-wood floor (or any wood floor for that matter) if it is exposed to flooding from a burst plumbing or heating pipe.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Guide to Choosing & Installing Engineered Wood Floors: Wood Laminates

Laminate and engineered wood flooring samples (C) Daniel FriedmanAs described in the book, Best Practices Guide to Residential Construction Chapter 5, Interior Finish:

The main advantage of engineered wood floors is dimensional stability.

[Click to enlarge any image]

Because most engineered floors consist of cross-laminated plies of wood, they are less likely to swell, shrink, cup, or warp.

This makes them the best choice for applications subject to wide changes in moisture levels— below grade, over radiant heating, or over concrete slabs with poor drainage or no vapor barrier.

Our photo (left) shows a selection of engineered wood and laminate flooring choices that we discuss here. (The first two samples from the left side of the photo are a resilient vinyl floor sample and a solid maple flooring sample and do not belong in the category of laminate nor engineered wood flooring.)

Laminated floors are also the best choice for glue-down applications because of their inherent stability. Another advantage is that engineered wood floors do not require a beveled edge. Most have tight-fitting, square-edged joints.

Materials Used in Engineered Wood Floors

Laminated floors come in a wide variety of sizes, from 1/4 to 3/4-inch thick. In general, the more plies a flooring has, the stronger and more stable it will be. Three plies is typical. Look for a top wear layer of at least 1/8-inch if the floor is to be sanded and refinished in the future.

Typical laminated floors can be sanded and refinished once or twice; the best, up to three or four times.

Figure 5-11: (C) J Wiley, S Bliss

The sanding thickness in some laminated flooring is nearly as thick as in traditional hardwood strip flooring, which although 3/4-inch thick, can be sanded down only about 1/4 inch (see Figure 5-11).

Longstrip flooring has several short pieces of strip flooring in the top ply to give the appearance of random length strip flooring.

Single panels are as large as 8x96 inches (see Figure 5-12). It is used primarily in floating floors, but some products may also be nailed or glued.

Since each panel is two or three strips wide, the end joints of these strips line up at panel ends, unlike in a true strip floor.

Single-strip flooring products, on the other hand, are visually indistinguishable from a traditional strip floor. Our photo (below right) illustrates an engineered wood floor product sample from Bruce® hardwood floors.

Figure 5-12: (C) J Wiley, S Bliss Engineered wood maple floor sample © D Friedman at

Veneers may be either sliced or rotary cut. Rotary-cut veneers make better use of the tree with less waste, but sliced veneers are harder and less prone to denting. Also, look for interior veneers that are the same wood as the face veneer or at least as hard. Soft interior veneers make a weaker flooring that is more prone to denting.

Installation Procedures for Engineered Wood Floors

Laminated wood floors can be nailed, stapled, or glued with mastic to any dry wood subfloor. Many can also be glued directly to dry concrete (see “Installing over Concrete,” page 168, for how to test dryness). If the concrete is below grade, check with the manufacturer to see if the product is guaranteed for that application.

A floating floor may be a better choice for below-grade applications.

In general, glue-down products are 1/4- to 3/8-inch thick parquet tiles, strips, or planks. Strips or planks are generally less than 2 feet long, since longer pieces are too difficult to straighten with glue. The only solid wood flooring that is glued is parquet, which gains stability from the short pieces and different orientations of the grain.

As with unfinished flooring, the building should be closed in, with all wet work completed and dried, before installing engineered wood flooring.

Make sure the concrete or subfloor is sufficiently dry and the indoor humidity level is close to the level it will be when the building is occupied. Keep the flooring materials packaged until installation.

Floating Floor Installation Methods for Engineered Wood Floors

Another option is to float the finish flooring. You can float a floor over virtually any stable substrate, including concrete, wood, smooth tile, or even short-nap carpet. With most floating floors, the T&G pieces are edge-glued to one another with PVA wood glue and installed over a thin layer of closed-cell, high-density foam and a vapor barrier.

A floating floor is more resilient underfoot than one glued to concrete, but feels less solid than a nailed or glued floor.

Some manufacturers offer a harder premium foam underlayment, which is recommended for those seeking a more solid feel underfoot. Still, customers should be aware that a floating floor will feel different from a nailed or glued floor.

Figure 5-13: (C) J Wiley, S Bliss

Installers must leave a 1/2-inch expansion gap around the edges of floating floors, typically hidden by baseboard, or use special T- or L-shaped moldings at door openings and other transitions to accommodate movement (Figure 5-13).

Existing door casings can be undercut to allow for movement. Restraining the flooring ends at doorways or the room perimeter can lead to open joints or buckling.

Because there are no mechanical fasteners to the substrate, floating floors rely on good quality flooring and a very flat slab or subfloor to produce a smooth, trouble-free floor.

In shopping for the flooring, choose materials that are straight and uniform in thickness, fit together snugly, and lay flat with few visible gaps.

The subfloor should be level to within 1/8-inch over 10 feet. If necessary, shim low points with clean mason’s sand or felt or rosin paper layered in the low spots to create a tapered shim (do not use asphalt felt over radiant floors, however, to avoid fumes).

While floating floors cannot tolerate the heavy vibration caused by standard floor sanding equipment, most floating wood floors can be lightly sanded and refinished or coated with sandless finishes.

Follow the manufacturer’s recommendations regarding refinishing.

No-Glue Installation Method for Engineered Wood Floors

No-glue longstrip flooring is available from Alloc, Inc. and BHK of America (see Buy Interior Finish Product Resources).

Each company uses its own interlocking edge design to snap the 8x48-inch or 8x96-inch panels together in place of adhesive. These products were developed in Europe where people often take their floors with them when they move.

Figure 5-14: (C) J Wiley, S Bliss

The Denmark-based company Junckers Hardwood Inc. manufactures the only solid-hardwood floating floor.

The 6-foot-long strips are held together with special metal clips that snap in place on the underside of the floor (Figure 5-14).

The clips, along with adhesive at butt joints only, work together to create a strong monolithic floor with the appearance of traditional strip flooring but the ability to move with moisture and temperature changes, making it ideal for use over radiant slabs.

The 5-inch-wide boards are either a single plank in width or two strips dovetailed together. The 9/16 -inch product is guaranteed for two sandings, the 3/5-inch for seven.

Bamboo Flooring Sources, Properties, Installation Guide

A recent introduction to the flooring market, bamboo is not really a wood, but a type of grass that matures in three to five years on plantations, making it an environmentally friendly alternative to premium hardwoods.

To make bamboo into flooring, thin strips are laminated to form planks from 3/8 to 3/4 inch thick.

The familiar nodes that separate bamboo stalks into short sections create darker cross markings, giving the product an attractive and unusual appearance.

A more homogenous color is also available from some manufacturers by using laminated strands. Engineered bamboo flooring is as hard as maple and more stable than oak, and comes either unfinished or prefinished with the same types of finishes as used on hardwood flooring.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Formaldehyde Warnings for Some Laminated Flooring Products: Lumber Liquidators

On Sunday [1 March 2015], CBS News' "60 Minutes" aired a program in which it had independent laboratories test laminate flooring from Lumber Liquidators for high concentrations of formaldehyde. The show said that samples of the flooring had levels of formaldehyde well in excess of limits set by the California Air Resources Board.

Lumber Liquidators said Monday that the news program used an improper testing method and that it stands by its products. - retrieved 5 March 2015, original source:

The New York Times, reporting on this program cited independent tests by investors Whitney Tilson and Xuhua Zhou dating as early as 2013 and producing results indicating [Tilson] "... formaldehyde levels in the wood he tested were two to six times the California limits". - Rachel Abrams and Aaron M. Kessler, "Lumber Liquidators Plunges After TV Report of Tainted Flooring", The New York Times, 5 March 20915, p. B2.

See FORMALDEHYDE in LAMINATE FLOORING for a discussion about testing & remediation of Chinese-made Freight Liquidators laminate flooring suspected of outgassing formaldehyde at hazardous levels. Quoting from that article:

Watch out: no gas exposure test will accurately describe the actual human exposure levels in a building if the test is not properly conducted.

The risks are of both Type 1 Errors (a false positive result) and Type 2 Errors (a false negative result). That is to say that depending on how it was conducted, your test may indicate a costly, actionable problem where in fact there is not one (a false positive) or your formaldehyde (or any other) test may indicate that there is no hazard or no problem when in truth there is one (a false negative result).

See FORMALDEHYDE GAS TEST KITS, METERS for help in choosing a formaldehyde outgassing or exposure test method, tool, or service.

See GAS EXPOSURE LIMITS & STANDARDS for formaldehyde gase exposure limits & standards


Manufacturers, Industry Associations, & Sources of Indoor Engineered Wood and Wood Laminate Flooring Materials

at FLOOR, WOOD ENGINEERED & LAMINATED we define three basic types of flooring products: hardwood flooring, engineered wood flooring, and laminate flooring. We illustrate each of these floor covering approaches with flooring sample photographs. Excerpts are bgelow

  1. [Solid] Hardwood flooring is illustrated by our photo at below-left. This hardwood flooring sample is Vintage Maple Natural 3/4" thick x 3 1/4" wide tongue and groove flooring produced by Tarkett and has a hardness rating of 4 on a 1 to 5 scale.

    Solid hardwood flooring is just that - flooring material made out of a single piece of hardwood, usually cut into a tongue-and-groove profile that is installed to the subfloor by nailing through the tongue on a diagonal into the floor board and into the subfloor below.
  2. Engineered wood flooring is illustrated by our second photo at below right. Shown is Click Bamboo-Toast 9/16" flooring available through Home Depot® stores.

    Engineered wood flooring combines a top layer of wood that is bonded to multiple plies of softwood that affords uniformity and dimensional stability.
  3. Laminate flooring, including laminate wood flooring looks like a hardwood floor, provides a hard surable surface, but is usually less costly per square foot than the solid or engineered wood floor products above.

Prefinished Wood Flooring

Bamboo Flooring Producers & Sources

Resilient Flooring Manufacturers List

Cork Flooring Manufacturers & Sources

Industry & Trade Associations for Flooring

-- Adapted with permission from Best Practices Guide to Residential Construction.


Continue reading at WOOD FLOOR ENGINEERED & SOLID or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see FORMALDEHYDE TESTS for FLOORING, a discussion of testing for formaldehyde outgassing from Chinese made laminate flooring

Or see FLOOR, WOOD ENGINEERED & LAMINATED where we define three basic types of flooring products: hardwood flooring, engineered wood flooring, and laminate flooring.

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FLOOR, WOOD ENGINEERED, LAMINATE, INSTALL at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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Publisher - Daniel Friedman