How to make things reversible: adapting patterns

According to the 'What brings you here?' poll, a large percentage of you lot are hoping I'll give you something or tell you something useful. I've been doing a fair amount of giving recently with pattern giveaways, but as yet, I haven't told you anything useful.

But what do I have to offer?! I haven't been sewing long enough to be an authority and I'm not formally trained so I'm hardly going to tell you how to do technical things... There are, however, quite a few posts on the board on Craftster asking how to make different things reversible. And reversible I do know a bit about. You'd cry if I told you how many hours I've lay in bed trying to figure it out...

Here are the stages I go through:

Will it work?

The first thing you should think about is whether it's an appropriate style. Some styles would just be too bulky to reverse, for example, if there are ruffles, pleats or a lot of gathered seams. These styles might not sit well in duplicate.

Do I have to change the original pattern?

If your using an exisiting, non-reversible pattern as a basis (as opposed to something intended to be reversible), you might need to change some things first. Think about your seam allowances, particularly at the arm seam, armhole and the side seams. If the garment is close fitting like a fitted shirt, or you are reversing with bulky fabrics like fleece in a coat, make sure that the bulk of a second fabric (and a second set of seams) doesn't stop it fitting properly. You might want to add a bit extra width through the bodice, open up the armhole a bit and widen the sleeves.

Another consideration is hem allowances, as the allowances for hemming garments is likely to be more than you need to make it reversible. For example, if you are going to make a simple elasticated a-line skirt reversible, and your original pattern accommodated more than an inch for your hem, when you attach your two skirts together at the hem to make it reversible, you won't need that whole inch. At the dotted fold line (the actual length of your skirt), add your seam allowance for attaching the two fabrics together, and that is your new cut line. The same goes for your waistband foldover / elastic channel. Start from your fold lines and add seam allowances to figure out your new cutting edges.

The other alteration you might need to make is if your original pattern has fold overs for plackets. This predominantly effects tops that open down the front, like button up shirts, zippy hoodies and coats. This is what your original pattern might look like:

If you're making this type of clothing reversible, the excess at the foldover is redundant. Your dotted line is your actual finished edge, so start from there and add a seam allowance to accommodate stitching the two fabrics together. When you flip it right sides out, the dotted line will still be your finished edge.

I don't want to make this too much of a tome, so I'll do separate posts on the practicalities / technicalities of making things reversible soon. Apologies to the people who come for my scintillating chat and wit :)