THE GOODYEAR WELT
Sole Thickness: 8 mm = 0.32 inches.
If a rubber Vibram sole is added to this sole construction, the thickness of this sole will be 12 mm = 0.48 inches.
A heavier and sturdy construction, the Goodyear welt has been known historically for being the golden standard for quality shoemaking and it is synonymous with high quality footwear. The space enclosed by the welt is filled with shredded cork to add cushioning and breathability to the interior of the shoe. In the resoling process, the outsole can be removed without causing damage to the upper.
The Goodyear construction method is most popular in England as its weatherproofness becomes a utilitarian necessity to match its year-round rainy weather. It is known to be the most complex and sturdy construction available for shoes. The thickness of the sole will be 8 mm or 0.32 inches and it can go up from there depending on how many layers of leather the client wants for his soles. Each leather outsole addition comes in 4mm increments. This method also requires the most skilled craftsmanship as it is time consuming and laborious.
The two level stitching makes it incredibly easy to resole, making it the preferred construction by shoe repair shops. Because the welt performs as a buffer between the insole and the outsole, removing the old sole and attaching a new one can be done by machine or by hand. The extra cost that comes with this method is worthwhile as it allows repeated resoling, making it possible for a pair of shoes to last decades.