image of square layer from toni&guy's Australian website
Anyone who has trained in the salon with me, will tell you I have a thing against square layers. Mostly about using them in long hair. I had a client find me again 9 months after I moved to a different location in my salon group. She drove for an hour, and paid at least a third more, because I can get rid of her square layers, and she is one of many. I have rarely heard any long hair client in the last 10 years, ask me for a haircut that would require a square layer, yet I see so many coming to me with exactly that cut into their hair.
I have two main problems with the square layer technique. The first is the shape around the face. This haircut only really works well with a centre parting, as shifting the part to either side creates unwanted asymmetry. But even when styled to a centre part, there is usually a large gap left below the layer, because the hair around the ear is not thick enough to compensate for the hair that has been cut away. This is very noticeable on fine hair where it sometimes seems like only 10 hairs are left to define the face frame. On thick hair this cut often results in a mushroom shape. The layers on top lift, thanks to being cut shorter, and fill out till they fall into a strong weight area at the bottom of the layers. Below this layer there is now less hair to reach the base line, hence the mushroom. Curly haired girls are very often the victim of this one. The second problem is the back area below the crown. Most of the hair below the crown is not cut when the hair is overdirected upwards, but the hair above the crown, usually loses quite a bit comparatively. The result is a rounded area at the top of the head which then drops to a solid base line.
My solution to this problem is usually to do a version of an increase layer, or natural inversion. By overdirecting the hair from the sides to the desired parting, and elevating as much as needed, I can maintain weight over the ears, and get a more fluid distribution of weight throughout the layers. At the back I often connect long layers in the area under the crest of the head, with the inversion, by overdirecting the crown backwards to a vertical layer. In the consultation, I ask if the client feels top-heavy in their cut, and if they would like to see more strength in the line of hair falling in front of their shoulders. Invariably they say yes, and I tell them I am going to give them classic flowing layers that blend seamlessly throughout the shape. Because square layers are such a common haircut, some clients do not even know they can ask to fix these problems, and are usually grateful to you for fixing their hair problems.
The times when a square layer really works, is when doing a version of the lioness or a chick-mullet. It will give you lots of volume on top and leave you length in the back and remove a lot of weight in the face frame to allow for the jawline to be opened up. If this is what your client is asking for then the square layer is your place to start. The cut is definitely worth learning, as every style will eventually come back into fashion, and someone less mainstream will be wearing it anyway. The trick is in learning when to pull this one out of your trick bag, and when to leave it alone.