Pssst...They're called slubs.

Nubbies, knots, flecks, knobblies, tweedy-things…no matter what you call them, you’re probably talking about slubs. From barkcloth to wool upholstery fabric, and all kinds of blends in between, much mid-century fabric was all about the slubs. By definition, a slub is a soft lump or unevenness in a yarn, either an imperfection or created by design.

One of the early problems with automated carding and spinning processes was the appearance of an incidental section of the yarn that was fuller than the yarn was intended to be. This soft lump would have to be removed before the material would be ready for warping or twisting. Originally, there were standards set in place that established what was considered an acceptable amount of slubbed or nubby yarn for first quality grading and sale.

Over time, however, the concept of yarns containing a high count of slubs as a textural and style alternative began to develop. Slub yarn began to be used intentionally, especially in fabrics that were characterized by what is referred to as roves. Essentially, a rove is an intentional pattern of slub yarn that is produced when spinning and twisting machinery is adjusted to allow the presence of the fuller lumps in the yarn itself. The result is that when the fabric is woven, the slubs form a continuous pattern in the material.

While slubbed fabric was very popular for mid-century furniture and draperies, the presence of slub yarn, particularly in upholstery fabric, results in a lower level of durability than one finds in smooth, more tightly woven material, making it all the more amazing that some of our favorite pieces have been preserved with their original covering still intact. 

From wisegeek.com and wordnetweb.princeton.edu

My highly slubby sofa, with original upholstery fabric

Close-up of sofa upholstery fabric

My semi-slubby chair

Close-up of chair upholstery fabric

A few months ago, I found a set of drapes at an estate sale that must have originally been ceiling-to-floor and covered an entire wall. I got half a dozen huge panels for $5. The orange and green fabric is very slubbed and is so typically mid-century. I've literally covered everything that would sit still with the stuff, including my daughter's dining room chair seats, the seat of a desk chair at my house and several pieces we sold in our booth. I've made pillows out of it too, and I still have a ton of fabric left. I swear, every time I cut a piece off,  the stuff regenerates in the dark at night.

The oddly regenerating slubby fabric that will never be used up

One of the chair seats I've recovered with the drapery fabric

Slubby pillows in my TV room/grandson playroom

Some highly slubbed Robert Allen fabric I'm considering for a reupholstery project

modern-fabrics.com