Measure the length, width, and height of your pet bed. Add a few inches to each measurement to allow for seam allowances and a snug fit.
Lay the flat-weave rug flat on a clean surface. Using the measurements from step 1, mark the dimensions on the rug with chalk or a fabric marker. Cut the rug according to these dimensions.
Fold the edges of the rug pieces inward about 1 inch and pin them in place. Sew along the folded edges to create a clean hem, preventing fraying and giving the slipcover a finished look.
With the hemmed pieces, pin the sides together inside out (the patterned side should be facing inward). Sew the pieces together along the edges, leaving one side open for inserting the pet bed.
For easy removal and washing, add a closure to the open side. You can sew Velcro strips along the open edge or attach a zipper. This step is optional but recommended for convenience.
Turn the slipcover right side out and fit it over your pet bed. Adjust the fit as needed and ensure the closure works properly.
Smooth out any wrinkles and make sure the slipcover fits snugly. Trim any excess threads and make any necessary adjustments to ensure a perfect fit.