Of all the various mending tasks that I undertake, the most frequent (and sometimes most onerous) is The Mending Of The Knees.

Fortunately, this means I have learned much by trial and error – not to mention that I have already gotten all my pants-related swearing out of the way – and that I am ready to share my knowledge with you in a socially acceptable fashion.

While there are times when a simple zigzag stitch across a straight, clean rip will get the job done, I find that holes or uneven tears develop more frequently, and the pointers below are written with larger, trickier problems in mind.

Materials and Equipment

First, for all but the thinnest fabric you will need a heavy-duty needle for your machine, or a substantial hand-sewing needle and at least one thimble that fits you well. Personally, I prefer to work with two thimbles when sewing heavy fabric by hand – one for my thumb and one for my middle finger – but that may not work for everyone. Make sure that your needles are sharp either because they’re right out of the box or because you’ve employed the sandpaper trick.

You’ll also need either a seam ripper or a small pair of scissors and a good light source. Even though I somehow lucked out and don’t yet wear glasses or contacts, I make sure I have plenty of light before I start working on a pair of pants.

You’ll need material with which to patch, too. Ideally, this will be heavier-weight fabric like denim or sturdy corduroy. If you want to reinforce the knees on the inside of the pants, as I do, you’ll need additional material of a similar weight.

Patches: DIY or Ready-Made?

If you want to use iron-on patches, you’ll need either ready-made patches or double-sided fusible web to make your own patches (if you don’t have an iron or prefer to use the sewing-only method, Verdant Toes’ Instructable on patching knees is excellent). I always make my own iron-on patches using a medium-weight fusible web, and I try to make several large sets – just rectangles about four inches by three inches with rounded corners – at a time so that they’re ready when I need them (they can always be cut down to size). I am not crazy about the look of iron-on denim patches that are sold seemingly for the express purpose of patching jeans, but to be completely honest those patches are the fastest and easiest things to use. Dritz, maker of many notions, also offers (or offered) iron-on patches with a little more swing in their step, so if you (or your kids) prefer something more colorful but don’t want to fuss with making your own patches, the fashion patches might be an option. (Sew, Mama, Sew! has a good tutorial on machine appliqués, much of which can be applied to the creation of your own patches.)

Catching Problems Early

It might go without saying, but the sooner the better when it comes to mending or reinforcing knees that are showing wear. Culling clothes to be mended from the rotation can backfire if you can’t get to the task within a few days, and you can end up – as I did recently – finding a comparatively perfect pair of pants on the mending pile that should have been pressed into service months before. Cue swearing.

Step One: Ripping the Outside Seam

Once you’ve amassed your materials (including your patches, whether purchased or made), identified your target, and set aside some time to complete the repairs, the fun begins. The very first thing you should do is get your seam ripper or small scissors out and open up the side seam of the leg you want to mend, going about two to three inches beyond the location of the repair so that the fabric will lie flat. Don’t open the flat fell inside seam – the outside seam that is more than likely finished on the inside with overlock and some straight stitching. I realize that (carefully!) ripping open the leg of the pants you need to repair may seem counterproductive or an unnecessary step, but if you have ever tried to mend small, narrow pants legs before and sewn the leg shut at the knee or otherwise wrestled with mending pants, you will probably agree that this is the better, if slightly more time-consuming, method.

Step Two: Ironing, Trimming, and Double-Checking

After you have opened up the leg that needs work, iron it so that it is as flat as possible. If the worn or torn portion of the fabric is bulky with out-of-place strings, cut them away neatly. Make sure your patch covers the area to be mended to about an inch beyond the place where the fabric is compromised. Don’t iron it on yet – you first want to stitch any reinforcement material to the inside of the leg so that the iron-on adhesive in the patch affixes itself to the inside/reinforcing layer of fabric instead of your ironing board.

Step Three: Reinforcing the Inside Knee

Reinforcing the inside knee area was a necessary step I figured out early in my pants-mending career. The photo at left shows the inside of a patched and reinforced pair of jeans. The stitching in the center of the larger rectangle is where the iron-on patch is sewn around its edges – the final step in my approach to mending knees. To prevent the fraying of the edges of the reinforcement seen here, cut out the reinforcing material using pinking shears instead of straight scissors. If the not-usually-visible fraying doesn’t bother you (or the pants-wearer, more importantly), just trim the strings now and again after laundering. To attach the reinforcement, just sew around the rectangle using your favorite stitch. If you’re using thread that will end up contrasting with the right side of the pants, take more care with making your stitches straight as this will end up looking like topstitching.

Step Four: Attaching the Patch

Once the reinforcement is in place, give it a quick press and flip the pants over to attach the iron-on patch to the front side. Align the patch so that its center is in the center of the trouble spot, and iron it on according to the directions either for the pre-made patch or the fusible web. I always use a press cloth for this portion of the project to keep the fusible web from adhering to the iron if something begins to slip. My press cloth is a clean scrap of muslin about the size of a piece of notebook paper. A clean scrap of cotton fabric is all you really need. Avoid using blends unless you are absolutely, positively certain they can take the heat needed to fuse the patch to the front of the pants without melting all over your iron and somebody’s britches.

(Note from Jo:  If you DO get iron-on goo all over your iron,  A) rub a bit of beeswax onto the hot iron and scrub all the goo off onto an old towel, B) use a commercially available iron cleaner, or C) allow your iron to cool completely and use a magic eraser to remove the gunk.)

If there is a hole all the way through the fabric at the knee, the adhesive will bond the fabric of the patch to the reinforcing material in this spot. If you are just ironing on a patch without reinforcing the inside of the knee, you must put down some kind of barrier between the patch and the top of your ironing board; otherwise your patch will attach itself to your ironing board cover as well as the pants. Before I began reinforcing the inside of knees I was mending, I placed a rectangle of kitchen parchment paper between the back of the patch and the ironing board. While this will eventually become brittle and need to be replaced, I never had a problem with the parchment melting or sticking to anything.

Step Five: Stitching the Patch

I confess that I sometimes skip this step, though the addition of stitching to the edge of the patch gives a more finished appearance. As long as the patch fused completely during the previous step, I have found that the weak spot will need another repair before the edges of the ironed-on patch begin to separate from the fabric below, particularly when the corners of the patch are rounded. I have found it’s a little easier to add a patch atop a previous patch that was not stitched, but as I mentioned the stitching imparts a certain look. Whether you stitch over the edges of the patch or not depends upon your needs and the likelihood that the knees will need to be repaired again.

Step Six: Closing the Outside Seam

Once you are satisfied with the amount of stitching present, turn the pants inside-out again, pin the open side back together, and stitch closed. Start with a straight stitch, finish the inside edge with a serger or using a zigzag stitch, and you’re finished!