Interfacing – Buttonholes need to be stabilised first, before the stitching is sewn and the hole is created, using interfacing.
As a general rule, buttonholes should be 3mm bigger than the button diameter. Buttonhole placement.
1 : a slit or loop through which a button is passed. 2 chiefly British : boutonniere. buttonhole. verb (1) buttonholed; buttonholing; buttonholes.
Horizontal buttonholes should extend 1/8 inch over the center front or back toward the garment edge. Vertical buttonholes should be sewn on the center front or back lines and are best for garments with a banded or placket opening.
If you are using woven fabrics, choose a lightweight fusible interfacing, purchased either by the bolt or pre-packaged. If using a knit fabric, choose a knit interfacing. If you don’t choose a knit interfacing, you will lose all the stretch in your fabric.