Making your own winter coat has one great advantage, especially for a large woman, it allows you to, coordinate design and selection of fabric most flattering for you. Alas winter coats by design are intended to be loose with heavier fabrics for warmth---making most large women look like mini battleships. But take heart, --with the right design and fabric, even a winter coat can make a large woman look "smashing."
Because of the simple design of most coats, sewing a winter coat is more a problem related to the added volume than design. Today, several fabric stores now carry outdoor fabric--water resistant and insulated. The fabric is expensive and as Tennessee only occasionally requires a coat for below freezing temperatures, for me, not worth the expense.
Another fabric available, and one I have used is bonded synthetic sherpa. This fabric is two sided with a sheared wool look on one side, and a "skin" on the other. The sherpa is for temperatures from 50 to 30 degrees, it is warm enough to stave off a chilly night, but shouldn't be used if you need serious warmth. You can do a lot with the fabric as it has a realistic look, is very light weight, and, can take limited washings. Since it doesn't fray, to avoid bulky hems, I hand stitched a blanket stitch around the coat.
Hemming the coat would have created too much bulk around the hemmed areas, and my sewing machine could not do a decorative stitch large enough in proportion to the coat to look right, so I did a chain stitch with acrylic thread
Generally, my go to winter fabric for winter coats is true upholstery fabric. This fabric is dense, can be washed and gives you great flexibility for texture, color and design. The negative is that unlike down filled outdoor coats, these coats can get heavy. There are several sprays and treatments that can be added to the coat, after it is made to make it water resistant, but this treatment will wash out.
Upholstery fabric often has stronger design more appropriate for winter coats.
More available colors to complement your tones,
Patterns are larger
Fabric stronger and more suitable for outerwear
Convincing your sewing machine to hem, upholstery fabric and lining, may not go well--since most of us do not have a commercial sewing machine. I believe like me, you will find your sewing machine can handle the thicknesses with a straight stitch, but probably won't be able to do many of the decorative stitches available on your machine. There are some good sources available for learning how to decoratively hand stitch your coat. An even easier solution for finishing coat hems is to use upholstery trim. Most fashion trim will be too thin for your coat. Upholstery trim can be washed, and comes in good sizes to accent winter coats. Also, don't forget about grosgrain ribbon which is very appropriate for trimming out winter coats.
Washing your fabric
Most fabrics wash well
Even the chenille washed well, although it flattened a little.
A caution regarding washing your upholstery fabric. Returning to my philosophy, if the fabric doesn't survive the wash, I throw it out. Ironically, I have yet to throw out any fabric. If you go to my Pinterest site you will notice the upholstery side of my fur coat. That fabric was pre washed in hot water. It actually has a chenille thread, blue, grey and cream and rayon which gives it a shiny look. I didn't iron the fabric, left it as it was, and cut the jacket. The shrinkage, gives me a denser fabric, although the chenille is a little flatter, the washing gives the fabric an over all warm pleasant look.
Most upholstery fabric will unravel more so than fashion fabric. So, either anticipate a little loss during the wash, or zigzag your raw ends before putting the fabric in the wash. Avoid unnecessary cutting--throwing one piece into the wash will limit loss of fabric.
Notions unique to the fabric
You will need upholstery thread and an upholstery needle to sew the winter coat. If you sew with regular thread, the weight of the fabric will wear out the thread, and tear seams. Upholstery thread is strong enough to hold the fabric weight. You will need the needle to plow through the thickness and not bend from the strength of the thread. Therefore, you will need both upholstery thread and needle.
At one time heavy duty polyester thread was being suggested as a replacement for upholstery thread. If you are absolutely desperate, this can be used, however, upholstery thread is made of nylon and is much stronger.
You will want to line the jacket as the under side of upholstery fabric can be rough. The weight of the lining will have to be appropriate for the fabric. If you select fabric too light, over a period of time, the lining will tear. Remember to preshrink this fabric also.
Join me next time when we will make a sherpa coat.