What Is Sanforisation? Sanforised and Sanforising Explained for Interior Designers

What it is: A mechanical pre-shrinking finishing process applied to woven fabric before it leaves the mill. Named after Sanford Lockwood Cluett, who patented the process in 1930.
Which fabrics: Most commonly applied to cotton and linen. Also used on some cotton-blend upholstery and shirting fabrics.
Why it matters: Fabric that has not been sanforised may shrink when used in curtains or upholstery that are subsequently washed or exposed to moisture. Sanforised fabric has been pre-shrunk to defined limits at the mill, reducing but not eliminating subsequent shrinkage.
On the label: Sanforised is a registered trademark. Fabric labelled Sanforised has been tested and certified to shrink no more than 1% in either direction. Sanforised-Plus is the rating for fabrics with even greater dimensional stability.

Sanforising is a mechanical finishing process applied to woven fabric to reduce the shrinkage that would otherwise occur when the fabric is exposed to moisture or heat after making up. Interior designers encounter the term on fabric data sheets and labels, most commonly on cotton and linen upholstery and curtain fabrics. Understanding what it means and what it does not guarantee is a practical specification consideration.

How the Process Works

Sanforising passes the woven fabric through a machine that compresses it mechanically in the warp direction — along the length of the fabric. A rubber blanket is stretched and then released, and the fabric is carried through this process so that the yarns are forced into a more compact arrangement in the warp direction before they are set by steam. The result is a fabric whose yarns have already been displaced into the position they would naturally move to if the fabric were washed. When the finished curtain or upholstered piece is subsequently washed or exposed to moisture, the fabric has less remaining tendency to shrink because the displacement has already occurred.

The process addresses warp shrinkage — shrinkage along the length of the fabric. Weft shrinkage — shrinkage across the width — is controlled by a separate process called tentering, in which the fabric is held to a defined width during drying and heat setting. Sanforised fabric has typically been through both processes.

What Sanforised Means on a Label

Sanforised is a registered trademark owned by Cluett, Peabody and Co. Fabric carrying the Sanforised mark has been independently tested and certified to shrink no more than 1% in either the warp or weft direction when washed. This is the residual shrinkage after the sanforising process — fabric may still shrink by up to 1% in each direction, but no more.

Sanforised-Plus is a higher standard, certifying residual shrinkage of no more than 0.5% in either direction. It appears on some high-quality cotton fabrics and performance linens.

Fabric described as pre-shrunk rather than Sanforised may have been through a similar mechanical process but without independent certification to the same standard. The level of residual shrinkage permitted under a pre-shrunk claim is not standardised.

What It Does Not Guarantee

Sanforised certification applies to shrinkage caused by washing. It does not address all the dimensional changes that fabric may undergo in use. Natural fibre fabrics — cotton and linen in particular — absorb and release atmospheric moisture as humidity changes. This hygroscopic behaviour causes minor dimensional changes that are distinct from washing shrinkage and are not addressed by sanforising. In environments with significant humidity variation — a room that alternates between very dry and very damp conditions — even sanforised linen or cotton may show minor dimensional change over time.

Sanforised certification also does not address the relaxation shrinkage that may occur in curtains hung under their own weight over time, particularly in heavy cotton or linen fabrics. This is a tension-release effect rather than a moisture-induced shrinkage and is unrelated to the sanforising process.

Relevance for Upholstery Specification

For upholstery fabrics that will not be washed — most contract upholstery is dry-clean or spot-clean only — sanforised certification has limited direct relevance to the face fabric performance. Where it matters most is in curtain fabrics that will be laundered, and in loose covers and cushion covers in domestic settings where machine washing is planned.

For linen upholstery fabrics, the dimensional stability of the fabric during making-up is more practically significant than its washing shrinkage. A fabric that relaxes or distorts during the tension applied in upholstery construction will affect the alignment of the finished piece regardless of its sanforised status. Confirm dimensional stability under tension with the supplier for any linen or cotton fabric being used in tight upholstery applications.

For linen upholstery fabric specification, see our upholstery linen page. For fabric care and cleaning codes, see our fabric care symbols guide. For fabric hand and how natural fibres behave in use, see our fabric hand and tactile properties guide.