Unravelling textile testing | Seam slippage

Usually occurring along a sewn seam or join, seam slippage is the separation or pulling apart of yarns. Generally, the yarns separate instead of actually breaking, leaving an unsightly gap.

Although seam slippage may be the result of a poorly constructed textile and/or the use of defective yarns in the fabric, it is more commonly due to an inadequate standard of upholstery manufacturing. This could refer to an insufficient seam allowance, a deficient number of stitches in the seam, or the failure to overlock raw edges during the upholstery process – or a combination of the three.

Seam slippage usually occurs when joins are subjected to a heavy load and pressure, such as seat cushions and armrests. Furniture styles such as tub chairs or those with a fixed back or seat cushion put more stress on fabric seams.

Yes, it can.

Linen, for example, is beloved as a smooth, lustrous fibre but this can make it more susceptible to seam slippage. For some linen textiles we would recommend discussing the need for reinforcing upholstery seams with your upholsterer.

No, it doesn’t infer inferior quality. If we’ve specified a fabric for upholstery then it is fit for purpose, but we recommend additional seam support for that particular textile.

‘Reinforce upholstery seams’ suggests employing an additional safeguard by stitching a tape along the seam to prevent fraying in high-load areas, such as the corner back cushions. Overlocking should be used for loose woven fabrics and seated cushion seams.

It is difficult to repair seam slippage once it starts. In almost all instances of seam slippage, it will require the furniture to be recovered or re-upholstered.

It’s important to ascertain the cause of the seam slippage. If it can be identified as a result of inadequate manufacturing, you’ll need to work with the upholsterer to ensure appropriate manufacturing techniques are being used, including reinforcing seams if required.

If the seam slippage is clearly related to the fabric, the furniture would need to be recovered with fabric from a different batch (if it’s an isolated batch issue) or with an alternative fabric which is more suitable to the particular frame.

The test measures how resistant a fabric is to yarns opening/slipping under pressure along the seam line.

Two fabric swatches are sewn together with a standardised seam, then pulled apart with an equal and opposite force. The test is performed in both warp and weft directions. Any seam opening is measured while the fabric swatches are being pulled apart. According to the Australian standard, a seam opening should be less than 6mm at maximum force. A lower result indicates a smaller opening and thus a better resistance to seam slippage.