Similar to iron-on patches, iron-on adhesive tape allows you to bond two pieces of fabric together without the hassle of a needle and thread. Place the double-sided strip of adhesive between two pieces of fabric and apply high heat to hem trousers quickly and securely. Depending on the type pf adhesive used, the glue may or may not come off easily, so this method of hemming is best for clothes that don't shrink or won't require adjustments later.
Mark the garment's hem according to the length desired using a white fabric pencil. Delineate the fabric where the item will be folded. Leave a hem allowance of 2.5 to 5 cm (1 to 2 inches). Trim away the excess with fabric scissors.
Set the iron to the appropriate heat level. Use high heat for thicker fabrics such as denim.
Press the iron on top of the inside of the hem, preheating the fabric for bonding. Be prepared to place the tape right away.
Apply the adhesive tape horizontally along the edge of the marked hem, pressing down as you go. Do this on one side of the garment at a time.
Fold the bottom of your trousers along the marked line, pressing it down over the tape with one hand. With the other hand, press the iron on top of the fabric firmly. Hold the iron in place for at least five seconds to allow the tape to melt.
Place another piece of adhesive in the hem if you're shortening the fabric by more than 2.5 cm (1 inch) or if the adhesive doesn't cover the entire hem's width. This will bond the fabric more securely.
Preheat the clothing with the iron to keep the adhesive from sliding before it's ironed in place. Cut pieces of adhesive in advance according to length of the hem for quick placement. Remove paper backing in advance. For thicker fabrics such as denim, layer pieces of tape over each other to create a stronger bond.
Some brands of iron-on adhesive tape create a more secure stitch than others. Results may vary depending on how often the garment is washed, how much adhesive was used and the weight/texture of the garment. Do not use adhesive hemming on transparent, fine or delicate fabrics such as silk or lace as they can't conceal the adhesive if placed underneath.