“Winston, what is the etiquette/rule regarding cardigan buttons? I see you wear your bottom one undone (like a waistcoat) but is this necessary? Can all buttons be done up?”
Cardigans are one of winter’s greatest pleasures. There are few comparable feelings to that of the warmth and reassurance provided by a toasty lambswool six-buttoner underneath your suit as you step out on a chilly morning. Warmer than waistcoats and smarter than sweaters, they are a compromise between comfort and formality. They are often perceived as slightly geeky and even fuddy duddy; “My grandad wears them” sneer detractors and they are certainly less favourable for more formal occasions.
However, they are perfect for insulating against the punishing cold of the darker months and many chaps have begun to use them in their business winter wardrobes. For this purpose, merino wool is favoured for its fineness. Lambswool is acceptable but many view the weave as too thick and coarse for wearing with suits. However, I do not believe this applies to all weights of suit; a heavy-weight fabric easily stands up to its robustness.
The general preference for buttoning cardigans in a more formal ensemble seems to be to follow the practice of the waistcoat and leave the bottom button undone, however I have seen many who are fully buttoned. Many would argue that the cardigan is not subject to the same ‘rule’ as the waistcoat.
However, for me, this is an aesthetic point. As with the waistcoat, the unbuttoned bottom button forms an attractive inverted V-shape which mirrors that of the upper cardigan, exposing the shirt and tie. When it is fully buttoned, this ‘mock waistcoat’ effect is lost and the cardigan appears more restrictive. Unlike, for example, the double-breasted waistcoat, the cardigan does not have the structure to be fully secured and also play into the flow of the suit.
Even in a relatively informal outfit, without a suit, the bottom-unbuttoned cardigan, with its V-shaped symmetry, interacts more successfully with the other elements.
The other point to consider is that the top button of the cardigan, unlike the waistcoat, might also be unsecured. This allows more of the tie to be seen, particularly if the wearer likes a good tie arch. However, some consider this a little too informal, even rakish as the ‘mock waistcoat’ effect is no longer being followed, and the cardigan is essentially playing by its own rules, or rather, the wanton extravagance of its wearer.
So, in answer to the question originally posted, I would say no; the bottom button shouldn’t be secured. Undoing two buttons is perhaps a little extravagant, but undoing one at the top does provide an excellent stage for a statement necktie.