Carpet Installation Methods
Stretch-in Installation

There are situations in which the specifier will wish to utilize the stretch-in method. Its selection may be for one of the following reasons:

• Provides enhanced underfoot comfort, acoustical properties (i.e., higher noise reduction coefficients and higher impact noise ratings) when installed with separate cushion
• Increases thermal insulation (R-value)
• Can be used over floors that are unsuitable for glue-down
• Patterned carpet may be more easily matched
• Corrective measures, such as seam repair, may be easier to perform
• Removal costs usually are less than the removal of an adhered installation

Stretch-in installations should be avoided:

• On ramps and inclines
• Where office systems furniture and demountable partitions are utilized
• Where heavy rolling traffic is likely
• Where there is excessive humidity
• When carpet has a unitary backing or other backing systems designed only for glue-down installation
  Direct Glue-down Installation
• Suitable for rolling traffic and ramp areas
• Seams are more durable since there is no vertical flexing
• Minimized buckling in buildings that have HVAC systems turned off for extended periods of time
• No restretch situations
• Facilitates access to electrical and telephone lines under floor
• Practically eliminates incidences of seam peaking
• No restrictions to area size
• Intricate border and inlay possibilities
• Usually less expensive

Double Glue-down Installation

• Combines the stability of direct glue-down carpet with the cushioning benefits of a separate cushion, stretch-in installation
• Improves carpet appearance retention, foot comfort and overall performance
• Simplifies carpet bordering and inlaying
• Suitable for wheeled traffic areas
• No restrictions to size of area

Article Credit: http://www.carpet-rug.com/