Canvas patio awnings are great for providing a shaded area outdoors. They are made with a durable awning fabric specially designed to withstand the sun and rain for years. As tough as they are, however, there may come a time when they will need repairs. You can easily perform these repairs yourself, and fixing a little problem now may prevent having a big problem later.
Rather than removing the whole canvas awning to do the repairs, the best way to repair it is to repair it in place. The most common areas of a canvas patio awning that need repair are small rips and tears in the body of the awning, and where the frame has worn holes in the corners of the awning. Contact an awning fabricator to buy a yard of fabric in the same pattern as your awning. Most awning fabricators use the same fabric suppliers, so any of them should be able to match your awning. If your awning pattern has been discontinued, or the fabric is unavailable, just pick any complementary color fabric.
For rips in the body of the canvas awning, cut a piece of replacement fabric that is 4 inches wider and 4 inches longer than the rip. This will give you a 2-inch reinforced repair on all sides of the rip. Using contact cement, paint one side of the repair patch and then paint the corresponding area on the underside of the awning, 2 inches beyond all sides of the rip. Let the contact cement dry according to the manufacturer's directions, then press the repair patch to the bottom of the awning. To achieve a good bond, it is helpful to have another person to press down from the top of the awning at the same time. Alternately, there are specialty repair tapes made for awning fabric (see Resources). For very small tears and holes in the canvas, you can simply apply a dab of clear silicone caulk with your finger to the area.
For corner rips, you may need to loosen each corner in order to access the underside of the canvas awning. Most canvas patio awnings are laced on with awning line. Unlace the awning far enough that you can lift up the corner. Follow the same procedure as for rips in the fabric body, cutting your repair fabric long enough and wide enough to extend beyond the rip. Glue it in place from the underside, pressing it well. Do not lace the awning corner back on until the glue has set up completely. Sometimes the corners are so badly ripped that a patch can't fix them. In that case, the best thing to do is to simply screw the fabric to the frame, at the corners, with small self-drilling screws. Screw from the outside of the fabric. This will hold the fabric securely in place and prevent further damage.