Rib knit and where it is used in underwear

Short answer: Rib stretches a great deal across and pulls back. That is why it appears in neck edges, cuffs, waistbands and sock legs.

How rib is built

Rib alternates between knit and purl in vertical columns, which gives the fabric grooves. The grooves can open and close like a concertina, which is why the fabric stretches a lot without stretching out.

Where you find it

Look at the places where a garment has to stretch over a head or a hand and then close tightly. The neck edge of a t-shirt, the cuff of a sweatshirt and the leg of a sock are all rib. See bamboo t-shirts for men.

Rib as the whole garment

Some undershirts and tank tops are knitted entirely in rib. They sit close to the body and follow movement. See bamboo undershirts for men and bamboo tank tops for men.

How rib wears out

Rib loses its pull when the elastane is broken down by heat. The edge then goes wavy and no longer sits flat. Wash cool to extend its life. See bamboo underwear for men.

Frequently asked questions

Is rib the same as elastic

No. Rib is a knit structure. Elastane is a fibre. The two are often used together.

Why does the rib edge go wavy

Because it has been stretched beyond its limit or because the elastane has broken down.

Can a wavy rib edge be repaired

An alterations shop can sew on a new edge. The old one cannot be tightened.