Interlock and why it holds its shape
Short answer: Interlock is two layers of jersey knitted together in one process, so the loops from both layers lock into each other. The fabric gets the same smooth surface on both sides, does not curl and stretches less than plain jersey.
How the fabric is built
In interlock, two rows of loops are knitted together in one process, so they lock into each other from each side. The result is a fabric with the same surface on the right side and the reverse, whereas plain jersey always shows a clear difference. The construction makes the fabric twice as thick as single jersey made from the same yarn, and noticeably more stable.
Why the edge lies flat
Because both layers carry the same tension, no force pulls an edge sideways in one direction. That is why an interlock garment can have an untreated edge that simply stays put, instead of curling the way plain jersey does. The same property also makes the fabric less prone to twisting after washing.
Where the thickness comes from
Because two layers are knitted as one, considerably more yarn per square metre is used than in single jersey. That gives a denser, heavier fabric that feels solid to wear, but also one that insulates more. The thickness is a direct result of the construction rather than of the yarn or fibre type itself.
Where interlock is used
Interlock typically shows up in underwear and sleepwear, where softness and shape stability both matter more than weight. See bamboo underwear for women and bamboo sleepwear for women. The fabric is also used in closer fitting t-shirts, where a surface is needed that does not fold or loosen after hours of wear.
The downside of interlock
Interlock is thicker and therefore warmer than single jersey, and it takes longer to dry after washing. For summer clothing, where avoiding sweat matters, single jersey is often the better choice. In return, interlock keeps its shape better through a full day, which makes the difference worth knowing before choosing a material.
How interlock feels against the skin
Because both sides are identical, the fabric sits stable against the skin without twisting during movement. That gives an even feel all the way round, unlike jersey, which can feel different depending on which side faces out. See bamboo t shirt for women, where interlock is often used in closer fitting styles.
Shape over time
Because the construction is denser and more stable, interlock loses less shape after repeated washing than loosely knitted fabrics. The garment stretches less at the waist and edges, which is especially noticeable in underwear, where elastic and shape need to hold without constant retightening over time.
Weight and comfort
Although interlock is thicker, it does not necessarily feel heavy to wear, because bamboo viscose itself is light and soft. The combination gives a fabric that feels solid without feeling stiff, which is one reason interlock is used widely in both underwear and everyday clothing for women.
How to recognise interlock
The easiest way to recognise interlock is to turn the garment inside out and look at the surface. If it looks like the right side, it is interlock. If there is instead a clear difference with visible ribs on the reverse, it is more likely plain single jersey or another type of knit.
Frequently asked questions
Frequently asked questions
Can you tell if a garment is interlock
Yes. Turn it inside out and look at the surface. If it looks equally smooth and structured on both sides, it is interlock rather than plain jersey.
Is interlock more expensive than plain jersey
Often a little, because more yarn per square metre is used and the knitting itself takes longer in production. The price difference is rarely large in the finished garment.
Does interlock shrink less than other fabrics
Yes, usually, because the double construction makes the fabric more stable in the wash. That gives less shrinkage in both length and width compared with loosely knitted alternatives.
You can find the full range at Bamboo-Clothing.com.
