What characteristic makes boucle fabrics more prone to seam slippage?

Boucle fabrics are characterized by their unique texture, which is created using looped yarns. The looser construction inherent in boucle fabrics contributes to their susceptibility to seam slippage. Since the loops form part of the surface and are not held tightly in place, they can shift or move easily when under stress or tension. This shifting can lead to the seams pulling apart or becoming misaligned.

In contrast, a tight construction would typically prevent this movement, as the threads are woven closely together, creating a more stable fabric structure that resists slippage. Similarly, while heavy weight can add some durability to a fabric, it does not inherently address the issue of seam slippage as effectively as the fabric's construction type does. Thus, it is the looser construction of boucle fabrics that primarily contributes to this characteristic behavior, making it essential for designers to consider seam strength and construction techniques when working with such textiles.