Area rugs are often sold in sizes that are not exactly the right size for your room or application. It is possible to join two rugs together into a single, larger rug, particularly if the smaller rugs are rectangular or square in shape and of a similar size. The easiest type of rug to join together are the edgeless, shag-style bathroom rugs that have a rubber backing. Other rugs, with edging, require a bit of deconstruction before you can join them together.
Decide which sides of the rugs you want to join together. Since most small area rugs have finished edges, one edge on each rug will need to be removed to bring the piles of the rugs together. Start at the corner and use a seam ripper to remove the crossover edge stitching. This usually extends at least 3/8 inch around the perimeter of the rug. Remove the edging just along the side you are joining.
Pull rug yarn out of the edging area with tweezers. Be careful not to cause a run and to remove yarn only from the edging area. Stop any runs or loose threads with fabric glue. You are trying to reveal the carpet backing fabric. Clean your rug this way along each edge where you will be joining the rugs.
Bring the top corners of the rug together. Fold the cleaned carpet backing fabric under and bring the piles of the carpet yarns together. Make sure you start at the very top of both rugs so that when you seam them together they will match exactly.
Thread a strong curved needle. Use a very heavy thread or double up to make your thread as strong as possible. Bring your needle up from the bottom through the edge of the folded carpet backer fabric. Pull your needle through until 2 inches remains on the end.
Cross over to the second rug and pierce down through the top and folded layer of that rug. You should be 1/8 inch away from the edge, making a 1/4-inch total stitch across the seam.
Hold the loose thread end and pull the stitch tight. Continue with tight stitches down the length of the rugs. A tight stitch is between 1/16 and 1/8 inch apart. Keep your rug edges flat as you sew. Your piles should be touching when the seam is in place.
Turn the rugs face down. Apply a bead of fabric glue under the open edge of the carpet backer fabric and press the backer firmly to itself. Measure, cut and apply 1 1/2-inch cotton tape over the glued seam once the glue has dried.
Stitch shag-type edgeless rugs together in much the same way, except you will not have an edge to remove.