Do Cloth Awnings Repel Water?

Waterproof Vs. Water Repellent

• During the course of a long storm, awning fabrics will eventually become soaked and drippy. Chemicals applied during manufacture help awnings repel water, which will often bead up, run off without incident or evaporate without leaking. Awnings are designed to be repellent rather than waterproof because their fine porosity is essential to their function, letting vapor and moisture trapped under the awning escape into dry air. A completely waterproof awning, such as you might make out of an impenetrable sheet of vinyl or plastic, can keep those under the awning from getting wet in a storm but offers no way to disperse steam from food, sweat from activity or even moisture from breathing. Awning fabrics therefore are designed to breathe as well as repel water and provide shade.

Types of Awning Fabric

• Awnings are usually made of one of four fabric types. Solution-dyed 100 percent acrylic offers a fine weave, quick-drying breathability and durable color. A factory-applied fluorocarbon finish-coating increases the fabrics water-repellent capacities. Acrylic-coated 100 percent polyester holds color well and provides sufficient weather-protection that it is often used for car- or boat-covers as well as awnings. Acrylic-coated polyester-cotton blends have a slightly coarser weave because of the inclusion of natural fibers. Applying a vinyl coating to cotton or polyester fabrics increases water-resistance to a high degree and makes these materials suitable for large, permanent awnings. Consumers may also find Teflon-coated fabrics that are both breathable and water-repellent when looking for awning material.

Selection Criteria

• Because these water-repellent methods all work at comparable levels, a consumer may feel comfortable basing choices on color selection and fabric finish as well as performance. If awnings are intended for year-round use, your choice may be influenced by how they will look against changing seasonal landscapes. If spring and early summer are your blooming seasons, green awnings may morph into too much late-summer green. If awnings are seasonal, think about how much contrast you want them to display in relation to the overall look of your house. Red stripes may look festive when first erected but less so as the season wears on. A blue-gray that echoes exterior trim might produce a more coherent and attractive facade over the long run.

Care Issues

• Awnings need regular washing, with low hose pressure and a mild soap, to maintain their good looks. While the fabrics do not themselves harbor mildew, it can grow on dirt that accumulates on awnings. Detergents can harm some water-repellent coatings and should not be used unless specified by the manufacturer or vendor of your awnings. Gentle scrubbing can remove bird deposits, sap drips and other dirt, but heavy scrubbing can damage coatings and weaken fabric. Check awnings at the beginning and end of each season for fading, tears and fiber deterioration.

Maintaining Water Repellence

• Manufacturers caution against supplementing factory-applied water-repellent coatings with do-it-yourself home water-repelling products. Products readily available to consumers may be designed for indoor use only and may conflict chemically with existing coatings. Some coatings can be reapplied professionally; ask about renewal when purchasing awning materials.