What Is Fabric Crazing?

If your Sunbrella^® Marine Grade or Awning/Shade fabric develops what looks like faint lines as you’re working on your projects, don’t panic. This is what’s known as crazing and it’s completely normal and to be expected. Luckily, this issue resolves itself in time, and we’re here to explain how this happens. Read on to learn more about what crazing is and what causes it.

Crazing lines can appear on any project that uses a stiff, heavy fabric, such as biminis and dodgers.

Crazing affects any solution-dyed, 100% acrylic fabric, and any fabric with a heavy coating. Crazing appears on your fabric when it is folded or creased, usually during patterning or sewing. The effect is most noticeable on light-colored solids, but may also appear on darker or heathered fabrics. Because Sunbrella Marine Grade and Awning/Shade fabrics are treated with a coating to make them water resistant and to increase stiffness, they have a heavier finish than other fabrics.

This is how crazing may appear on a Sunbrella Marine Grade fabric.

For popular applications of these fabrics — covers, biminis, dodgers — you want the stiff quality of the fabric. The stiffness makes the fabric easier to work with while patterning, sewing and installing your projects. But the resins that make the fabric stiff are also responsible for crazing. When the finish is disturbed, the result is a faint marbling effect. When heavy, stiff fabrics are folded, bunched or creased, light refracts differently against the surface where the finish has been disturbed. If you can picture light reflecting on the bottom of a pool, it looks a bit like that.

On the left is a freshly crumpled piece of stiff computer paper. You can see the shadows and lines that appear as a result of light refraction. On the right, this thinner piece of tissue has less light refraction. Over time, a stiff marine grade fabric will soften with use and exposure to the elements, and the crazing lines will eventually soften and fade.

Some crazing is generally unavoidable, but it isn’t permanent and it doesn’t affect the performance of the fabric. However, you may feel that it changes the look of your projects. Crazing lines will fade over time as the fabric is used and as the fabric softens with age.

One strategy to adopt when working with heavy fabrics is to be careful and mindful when handling the fabric. When sewing or patterning your fabric, try to avoid bunching or folding the material. Instead, scroll your fabric under the sewing machine arm as you work with it. You should also store unused fabric on the roll.

Remember, crazing can be annoying but it isn’t permanent. The effect will disappear naturally over time as the fabric is used and weathers.