One of the most telling indicators of the quality of a suit is whether the lining is canvassed or fused. There is a significant difference between the two suit construction techniques. They are relatively simple to tell apart and this specification is often what separates a basic suit structure that you'll probably only have a season or two from an investment piece you can wear for a lifetime.
The Canvassed Suit
A high quality men's suit jacket is constructed with an outside shell -- usually wool or a wool-blend fabric -- a comfortable satin-like lining on the inside and canvas in between the outer fabric and the lining. This canvas keeps the shape of the suit and prevents it from sagging or deforming over time. The canvas is cut to fit the shape of the jacket. A full canvas suit will have a canvas structure that covers the front of the jacket -- running all the way from the the top of the shoulder to the hem and spanning the entire inside front panels and lapels of the jacket. The canvas, the wool and the inside lining are all hand-stitched together. The canvas is made from a flexible but structured fabric that is meant to drape in a clean line and mold to the shape of the body after multiple wears for a superior fit.
The Fused Suit
A less expensive way to build a suit is to opt for a fusing technique instead of stitching a canvas. In a fused suit, a fusible interlining is glued to the wool fabric, resulting in one thicker piece of fabric that serves as the shell and is then sewn to the satin-like jacket lining. Fusing serves the same purpose as canvas -- to help the jacket keep its shape. Most suit suppliers, from high-end designers to mass retailers use fused construction in their suit jackets as a way to save them money and, in exchange, give you the option to save money as well, as this is a much less expensive and less laborious way to construct a suit.
Telling the Difference
To determine if a jacket is canvassed or fused you have to be a bit of a detective. Gently pinch and pull apart both sides of the cloth below the bottom buttonhole. If you feel a third layer floating inside, then the coat is fully canvassed. If you don’t feel a third layer -- if it feels like one thick piece of fabric and one thin satiny piece of fabric -- then the jacket is likely fused. However, advances in fusing technology have made it more difficult to tell the difference in some suits. Another technique for telling the difference is to look at the lapel. The reverse side of a canvassed lapel has stitching, where the canvas is sewn to the wool; a fused jacket doesn't require stitching, so you won't find thread there. In addition, fused jackets often appear more stiff than canvassed jackets because of the dried glue.
Fused Vs. Canvassed
A fused suit is going to be considerably more affordable than a canvassed suit, allowing you to try newer trends, colors and styles that diversify your look. This diversity comes with a risk. The glue in a fused suit does not interact well with water, heat or dry-cleaning solvents and will eventually bubble due to the lining and shell coming unglued from one another. This is not a problem a tailor can fix, so once that's happened your suit is rendered useless. A canvassed suit -- typically coming from a high-end designer -- has superior construction that will last longer and fit your body better. This quality is going to cost you a pretty penny though. A canvassed suit is an investment.