Unscrew the bolts that hold the awning onto the camper shell and remove the old awning. Keep it as a pattern for your new awning.
Measure the old awning to see how much canvas you need to buy. Purchase a little extra canvas for hemming and flaps.
Lay the new canvas on a large, flat surface. Do this outside on the grass if you don't have a large enough space inside the house.
Pin the old awning on top of the new canvas and cut out the new awning. Cut the new awning a little larger than the old one to allow for hemming. Allow an extra 5 inches on the side of the awning that will contain the grommets.
Turn under the edges of the canvas on the sides and front of the awning, pin in place and sew a hem using heavy-duty thread.
Lay the old awning on top of the new awning again and make marks for grommets on the outside of the new awning, 5 inches from the edge. Flip the new awning over. Turn the edges of the canvas under, leaving the grommet marks visible.
Use the grommet tool to attach grommets to the new awning. Follow the package directions for the particular tool you purchase.
Line up the grommets with the bolt holes in the camper shell. Insert the bolts to attach the new awning to your camper.