Understanding Solid and Engineered Bamboo Flooring

There are different processes that are used to turn bamboo grass materials into bamboo flooring planks ready for installation. Each manufacturing method produces a product with specific characteristics that may make it more or less desirable in a particular environment. By understanding the available options, you can choose the type of bamboo flooring that will work best for your project.

Traditional Use of Bamboo in Flooring

In its natural state, bamboo is the world’s largest species of grass. A tall, tubular plant, bamboo has a relatively hard outer shell that makes it suitable for some flooring applications, even in its raw state. Traditional flooring in Eastern Asia is made by slicing the stalks into thin sheets and then nailing them to hardwood beams. This is a flooring method that is still used in some rural areas to this day.

In modern flooring, bamboo is generally processed in different ways, although solid bamboo in a modified form still has its place. While some sources list as many as five different types of bamboo flooring, all types fall into two general categories: solid bamboo products, in which solid pieces or stands of bamboo are pressed and glued together to form flooring planks; and engineered bamboo flooring, which consists of a relatively thin surface layer of bamboo bonded to a wood or high-density fiberboard (HDF) substrate layer.

Solid Bamboo: Vertical Grain and Flat Grain

Flooring made from solid bamboo will give you the most natural look possible. The surface of materials has extremely rich features and the most interesting patterns. Solid bamboo flooring works well in bedrooms, living rooms, home offices, dens, and it can be also used in some kitchens if proper precautions are taken. This material should not be used in bathrooms or below-grade (basement) installations.

Manufacturing Process

While bamboo is fairly hard in its natural state, it is also brittle and uneven, and for that reason is not often used raw in modern flooring applications. Rather, the material is processed in such a way that the positive benefits of the bamboo are retained while also making it more versatile.

The first step in manufacturing solid bamboo floor planks is to slice the stalks of grass down into very thin pieces. The skin is removed from the material, and it is then boiled in boric acid. The acid helps to kill any microorganisms or bacteria that may be lurking in the bamboo, while also removing any lingering starches that may remain.

These individual slices are then coated with a special adhesive and are bonded together into solid pieces using heat and pressure. The way that the individual chips are lined up will determine the final appearance of the flooring. This takes one of two forms:

• Flat-grain: The chips are laid flat, one atop the other. This results in a floor with fewer features and a more consistent look. This is also the closest match to the actual appearance of natural bamboo materials. This is the most common type of bamboo flooring installed.
• Vertical-grain: The individual slats are lined up, straight up and down, and are bonded with pressure applied from both sides. While the result is still a natural bamboo look, these floors tend to have more mottled, busy features on their surface. This can be great for hiding dirt or giving a plain room a more interesting look.

Once the adhesive has dried, the material is planed and sanded down to ensure that they have smooth, even surfaces on every side. A UV lacquer is then applied to help the curing process. Finally, it is sanded one more time to complete the finish on the material.

The flooring sometimes is stained and finished before reaching retailers for consumer sale.

Installation

Both vertical-grain and horizontal-grain solid bamboo are typically sold as tongue-and-groove planks that are installed in much the same fashion as traditional hardwood flooring: blind nailing or adhesives.

Advantages

• Solid bamboo flooring can be sanded down and refinished periodically when scratches or dents appear.
• Because they are solid planks nailed or glued to a subfloor, these floors are rock solid, with no flex underfoot.
• Although they do use adhesives, there is less danger of outgassing than with strand-woven bamboo.

Disadvantages

• Solid planks are somewhat more difficult to install than click-and-lock engineered bamboo flooring.
• While still harder than most hardwood flooring materials, solid flat-grain or vertical-grain bamboo is less durable and resilient than strand-woven.
• Like all bamboo flooring, it should not be used in wet or damp locations, such as bathrooms or in below-grade applications.

Solid Bamboo: Strand-Woven

The other form of solid bamboo flooring also comes in planks that consist of bamboo from top to bottom, but instead of chips of bamboo bonded together, strand-woven bamboo is made from pulped bamboo that is pressed and formed into extremely dense blocks of solid material that are then sliced into flooring planks and tiles. Because the manufacturing process fully integrates the adhesive and the bamboo, and because more adhesive is used by a percentage of weight, strand-woven materials tend to be considerably harder and more durable than solid vertical-grain or horizontal-grain bamboo.

Strand-woven solid bamboo is suitable for any relatively dry, above-grade, interior installation, such as living rooms, hallways, and bedrooms. It should not be used in the bathroom or basement, and use caution when using it in kitchen installations.

Manufacturing Process

The manufacture of strand-woven bamboo begins when the stalks are sliced into strips and the skin is removed from them. The strips are then boiled in boric acid to remove the starch and kill any vermin. At that point, the stalks are placed into a shredder and processed down into a thick pulp in which individual strands of bamboo become tightly interwoven.

An adhesive substance is then mixed in with the pulp, and the material is injected into a mold. There, heat and pressure are used to force the mixture into a solid thick bar. Once the adhesive is fully dried, the bars are then sliced down into individual planks and tiles for flooring. Tongue-and-groove planks are the most common, though some strand-woven bamboo products use click-and-lock connection methods. The final material is planed and sanded multiple times to ensure a flat even surface on every side. A finishing agent or stain may also be applied before distribution.

Installation

Tongue-and-groove forms of strand-woven solid bamboo are installed in the same manner as traditional solid hardwood flooring—nailed or glued to a plywood or MDF subfloor. Click-lock forms of the product are “floating” floors that are installed so they float over a paper or foam underlayment, without permanent attachment to the subfloor.

Advantages

• Strand-woven bamboo is extremely hard—among the hardest and most durable of all flooring materials, including hardwoods.
• When scratches, dents, and other imperfections appear on the surface, it can be refinished, taking it down a layer to make the material look like new. The number of times it can be refinished over the years will depend on the thickness of the planks or tiles.

Disadvantages

• Solid planks are more difficult to install than click-and-lock engineered bamboo flooring.
• The adhesive used to make the material may cause the floor to emit harmful volatile organic compounds (VOCs).
• The manufacturing process removes some of the natural bamboo features from the floor, making it look slightly less natural and more processed.
• Like all bamboo, strand-woven flooring is suitable only for relatively dry locations. It should not be used in wet environments or below-grade.

 Engineered Bamboo Floors

While engineered flooring looks like it is made of solid pieces of bamboo, there is actually very little natural bamboo in each piece. Rather, the flooring planks consist of a relatively thin layer of natural bamboo adhered to a backing layer and topped with a wear layer. Engineered flooring is extremely stable and easy to maintain. It looks very much like real, natural bamboo, but without any of the hassle and concerns. Often available in click-together tiles and planks, it can be installed even by an amateur, and individual tiles can be removed and replaced if damaged. It can also be a better form of bamboo to use in wet environments, although this should be done with caution: Manufactures may void warranties if the product is installed in frequently wet environments where pooling water is a possibility.

When properly installed and maintained, engineered bamboo can be suitable for nearly any location, both above- and below-grade. In high traffic environments, you may want to purchase flooring with a thicker wear layer.

Manufacturing Process

The bamboo for engineered bamboo flooring is created in much the same way as for solid strand-woven bamboo. In this case, though, rather than solid bamboo flooring planks, thin veneer layers are cut from the molded blocks of bamboo. These thin sheets of processed bamboo are then bonded to a base layer of cross-laminated plywood or fiberboard. A clear wear layer is applied over the natural ply layer, and a waterproofing agent may be applied to the bottom of the sheets From these prepared sheets, flooring planks or tiles with tongue-and-groove or “click-lock” edges are cut for sale as commercial flooring materials.

Because of the surface wear layer and the waterproof undercoating used, these flooring products are considered more resistant to moisture and water than solid bamboo, though manufacturers rarely call their products truly waterproof.

Installation

Engineered bamboo flooring is the one form of bamboo that is relatively easy for amateurs to install. It is normally installed as a “floating” floor laid over a foam or membrane underlayment. Installation is similar to that of engineered wood flooring or laminate flooring. Click-lock products are designed so seams grip together without adhesives; some tongue-and-groove forms require edge gluing to hold the sides of the planks or tiles together.

Advantages

• This is the easiest of bamboo flooring products for DIYers to install themselves.
• Though not waterproof, the surface wear layer and a waterproof coating on the bottoms of the planks make engineered bamboo more resistant to moisture than solid bamboo.
• Those products made with cross-laminated wood substrates are very stable dimensionally; there is rarely any expansion and shrinkage problem due to seasonal climate changes.

Disadvantages

• You cannot refinish an engineered bamboo floor. While the wear layer is quite durable, it will degrade over time and once it does, the floor will need to be replaced.
• As a “floating floor,” there may be some flex to this floor; they are not as solid underfoot as solid nail-down bamboo.

Costs

Vertical-grain and horizontal-grain solid bamboo typically costs $2 to $4 per square foot for materials only, while strand-woven solid bamboo is slightly higher, at $3 to $5 per square foot. The longer lifespan of strand-woven bamboo, however, may equalize the price differences over the life of the flooring.

Engineered bamboo flooring costs are roughly comparable, running between $2 and $5 per square foot, depending on the thickness of the veneer and quality of the wear layer.