In most cases, carpeting isn’t kind to the wood that it’s attached to. Most carpet installation uses adhesive or nailing strips, both of which will damage wood. Conversely, you can choose to use an adhesive designed to be removed from wood, in which case carpeting can actually protect your hardwood stairs.

The cost to install carpet is $1,780 on average for 330 square feet, the size of an average living room. This cost could range from $200 to $5,000, depending on the amount of carpet, material, and type of carpet. 

If you need 500 square feet of carpet, it’ll cost $1,500 to $5,500, while 1,000 square feet of carpet costs $3,000 to $11,000. Polyester is one of the more affordable options, ranging from $1 to $3 per square foot. Wool is a more luxurious option, ranging from $4 to $20 per square foot. 

In most cases, you do not need to put padding or underlayment under carpet tiles. Unlike traditional carpet, which requires a separate pad, carpet tiles are designed to be installed directly onto a firm subfloor like plywood, concrete, or tile. Many carpet tiles come with a built-in underlay and attach with peel-and-stick adhesive, double-sided carpet tape, or glue. For a more comfortable, cushioned feel, especially in residential settings, you can opt for padded carpet tiles that have a thicker underlay attached. While it's generally not recommended to install a separate pad, a compact underlayment might be used in some situations, though this typically requires professional installation. An acoustic underlay may also be considered in commercial spaces or multi-level homes where noise reduction is a priority.

Carpet glue is very sticky, but it's not permanent. The glue usually lasts as long as a typical carpet installation, which is five to 15 years. For the best results, you should always use the right type of carpet glue for the area you're using it in. There are carpet glues for high-traffic areas, which are more high-quality and durable than others.