Flooring is an intimate building material. When indoors we're almost always in contact with it. Consequently, we demand a lot from flooring. In addition to being pleasing to the eye, it has to be comfortable underfoot, easily cleaned, hypoallergenic, smooth but not slippery, scratch and gouge resistant, durable, and easily refinished or replaced when it wears out. The ability to stand up to moisture is also important for bathrooms, kitchens and basements.

Wood Floors
Of the many flooring materials available to homeowners, solid wood is still the standard. It offers a multitude of design and finishing options, is easily repaired, can last several generations and, according to real estate agents, is a highly prized feature with home buyers.

Solid wood flooring is not recommended for moisture-prone areas, such as basements, bathrooms and kitchens, or in climates with high humidity. Moisture can cause wood to discolor, swell, cup and buckle. Dryness can cause problems, too. If a room is too dry and the moisture content of the wood flooring is high when it's installed, gaps or cracks may appear as the boards dry out and shrink. Manufactured so its moisture content is an average indoor humidity of 6 to 9 percent, wood flooring should be acclimated to the job site prior to installation.

Solid wood flooring is available in a variety of species and grades. Oak and ash, for example, are available in clear (free of knots), select (small knots and minor color variations) and common grades 1 and 2 (more knots and color variation). All of the grades are structurally sound, but each will give a different look, from formal to rustic.

Sold prefinished and unfinished, solid wood flooring is available in strips, planks and parquet. Strip thicknesses range from 5/16 to 3/4 in., widths from 1-1/2 to 2-1/4 in. Planks are 1/2 to 3/4 in. thick and 3 to 8 in. wide. Strips and planks may be plainsawn or quartersawn when they are milled from logs. Quartersawn boards, cut from logs that have been quartered first, have straighter grain patterns and are generally more stable than plainsawn stock. Parquet, which is usually square, is composed of small wood slats joined by adhesive and fasteners.

Material costs range from $2 per square foot for low-end parquet to more than $7 per square foot for prefinished plank flooring. Installed, site-finished, select oak strip flooring can easily top $14 per square foot. Site-finished plank and maple floors cost more.

Two lower-cost alternatives to solid wood flooring are engineered hardwood floors and longstrip plank floors. The first is made by gluing up three to five thin layers of hardwood, with the woodgrain of each layer perpendicular to the grain of the one below it. It is offered prefinished and unfinished in strip, plank and random plank styles. Longstrip planks are typically a 1/8-in. prefinished hardwood veneer glued to a plywood base. The planks look like three rows of prefinished strip flooring joined together.

Both engineered and longstrip flooring are more stable than solid wood products -- they can hold up to slightly moist conditions in basements and over concrete floors. Installation methods include gluing, stapling and floating -- the latter is when the boards are glued together but not attached to the floor. Both types of flooring can be sanded and refinished when necessary.

Plastic Laminate
In the last decade, high-pressure plastic laminate flooring products have earned a place in the market. Made to look similar to wood, they consist of protective and decorative layers that are bonded to a dense fiberboard core, backed with a moisture-resistant bottom layer -- sometimes with a sound-dampening underlayment as well. The decorative layer is typically printed on paper and embedded in resin. Plastic laminate flooring is similar to the laminate used for countertops, but it's much harder.

One big advantage of laminate flooring is that it can be used in moisture-prone areas where homeowners want the look of wood. Laminate manufacturers claim that their products are more dimensionally stable under moist conditions than wood flooring. Nevertheless, they warn that these products are not immune to moisture problems and that care must be taken in their installation. This includes doing a moisture test, acclimating the flooring prior to installation, and using vapor barriers and sealants.

Another advantage of plastic laminate is that you can float it (install it without glue or nails) over nearly any substrate including most old flooring. In addition, installation is relatively quick and suitable for do-it-yourselfers. Highly durable, plastic laminates are resistant to dents, stains, gouges and cigarette burns.

Disadvantages are few. The primary one is that most plastic laminate floors cannot be refinished like solid wood floors can if they are damaged or begin to show wear. Minor damage, such as a deep scratch, is more difficult to repair than with solid wood.

This flooring comes in various sizes, shapes, patterns and colors, including strip, plank and tile. It's offered in thicknesses that range from 5/16 to 5/8 in. Installed costs of laminate products -- $6 to $7 per square foot -- are typically less than site-finished solid wood and about the same as prefinished oak strip flooring.

Carpeting
Wall-to-wall carpeting is a quick, easy and relatively inexpensive flooring solution, often installed directly over the subfloor. It's available in a dizzying myriad of materials, from high-tech nylon fibers to traditional materials like wool. Carpeting has several advantages. It's a nice surface for your foot to touch first thing on a cold winter morning. Carpeting also can reduce noise in the home and provide a resilient, nonslip surface for weary legs.

Unfortunately, the less expensive grades of carpeting will begin to look worn relatively quickly. In general, carpeting is difficult to keep clean, despite stain-resistant fibers and coatings. It wears unevenly, is subject to fading in sunny rooms, and you typically have to replace it in eight to 10 years. The best grades will last longer, but are more expensive.

Installation costs for a better-grade, nylon-fiber carpet range from $4 to $5 per square foot, depending upon the size of the installation.

Resilient Flooring
Any man-made flooring product that has a firm surface but gives under pressure is considered resilient flooring. The first resilient flooring was introduced in the 12th or 13th century in the form of rubber tiles. Today, resilient flooring is made from vinyl, linoleum, rubber or cork, and is second only to carpeting in terms of sales.

The most popular resilient flooring is vinyl. It's made by bonding a protective clear layer, called the wear layer, to a decorative layer (either inlaid vinyl chips or a printed gelcoat) and finally to a felt backing. The thicker the wear layer, measured in mils, the more durable the product will be.

Vinyl flooring is available as tiles, strips and rolls in an enormous number of styles and colors, including wood and stone patterns. Best suited to kitchens and baths, it's easy to clean, moisture resistant and fairly durable if you buy a premium-quality product. Also, even a novice can install vinyl flooring, using very few tools. One drawback is that things like tracked-in driveway sealer, color markers and Kool-Aid can cause stains, especially on lower-end products. Better grades of vinyl sheet or tile flooring cost between $4 and $6 per square foot installed.

Linoleum waned in popularity as easy-care vinyl products became popular in the 1950s and '60s, but has experienced a comeback in recent years due to its beautiful vibrant colors, design flexibility and natural composition. Invented in the mid-1800s, linoleum is made from linseed oil, resins, cork powder, wood dust, ground limestone and pigments. Unlike vinyl, it is a nonpetroleum-based product and is completely recyclable. It wears well, thanks to colors and patterns that go completely through the wear layer of the product. Linoleum manufacturers say that its natural properties inhibit the breeding of some microorganisms and make it antistatic, so it repels dust and dirt.

Due to its porosity, linoleum is subject to staining and requires periodic polishing. It is not as resilient as vinyl, and areas not exposed to light will take on a temporary yellowish cast. Linoleum is not recommended for below-grade installations or in bathrooms, and is best installed by a professional. Its cost is between $9 and $10 per square foot installed.

Cork and rubber are two other forms of resilient flooring. Some homeowners like cork for its warm, soft feel underfoot and the fact that it's slip resistant. It comes in natural wood tones and colors, and is typically finished with water-based varnishes. Rubber is also very resilient and slip resistant, but is subject to staining from grease and oil. It requires no finish and is available in colorful studded and ribbed rolls, and tiles. Both products should be installed by a professional.

Masonry Flooring
Masonry floors include ceramic and marble tile, decorative concrete and stone. Ceramic tile is by far the leader in this category. It's beautiful, natural, easy to clean, extremely durable, resistant to moisture, easy to install and available in hundreds of shapes and styles -- including stone patterns that are extremely natural looking. On the other hand, tile is cool and hard to the touch. High-gloss glazes should be avoided due to their slipperiness when wet. Opt for slip-resistant glazes. Installed ceramic tile costs about $10 per square foot.

Decorative concrete flooring is gaining popularity thanks to companies that have devised ways to pour thin-but-strong layers of concrete over various substrates. They then use acid stains that create stonelike visual effects and colors on the smooth concrete surface. Once polished, these floors require little maintenance and are unaffected by moisture. When coupled with radiant heat in the floor, a cold floor temperature is no longer an issue. The cost for a decorative concrete floor including graphic patterns, staining, sealing and polishing is about $3 per square foot. Real stone, such as slate and granite, costs much more and requires regular maintenance.