Terminology

• Full-grain: hide with the grain layer intact; typically the highest quality
• Top-grain: grain layer sanded or buffed to remove blemishes
• Split: leather from the corium layer below the grain
• Bonded leather: 10 to 90 percent leather fibers, depending on the mix
• Wet white: chrome-free aldehyde-tanned leather
• Ounce (leather thickness): 1/64 in. (about 0.4 mm)

History and demand

Sourcing

• Cattle supply about 65 percent of leather, sheep 13 percent, goats 11 percent, pigs 10 percent; China and India are the leading producers

Composition and production

Manufacturing process

• Chrome tanning: most common method; about 80 percent of leather is chrome tanned
• Vegetable tanning: bark tannins
• Aldehyde tanning: chrome-free
• Alum tawing is not true tanning; the material reverts to rawhide if the alum is washed out

Product forms

• Sides and hides for upholstery, wrapped wall panels, and floor and wall tiles

Grades and types

• Full-grain: grain layer intact
• Top-grain: grain layer sanded
• Split: from the corium; thick hides split into middle and flesh splits
• Bonded: leather fibers in a binder
• Synthetic alternatives: polyurethane or vinyl coating on cloth backing

Properties

Physical

• Thickness: upholstery cowhide about 1.1 to 1.6 mm (0.043 to 0.063 in.)

Durability

• Lasts decades with maintenance; below 40 percent relative humidity leather can dry out
• Takes 25 to 40 years to decompose

Uses in buildings

Building elements

• Wall Cladding: leather-wrapped wall and ceiling panels on Baltic birch plywood or fire-rated substrate, hung with Z-clips
• Resilient Flooring: leather floor and wall tiles

Pros and cons

Pros

• Durable for decades; repairable
• Natural material in many finishes

Cons

• Tanning wastewater and chromium pollution when poorly managed
• Dries out below 40 percent relative humidity
• Slow to biodegrade

Sustainability

Embodied carbon

• Bovine leather carbon footprint 65 to 150 kg CO₂e per square meter

Health

• Tanning wastewater: 20 to 80 m³ per tonne of hide, chromium 100 to 400 mg/L, sulfide 200 to 800 mg/L; solid waste up to 70 percent of wet hide weight
• Trivalent chromium used in tanning is not toxic; other byproducts can be
• Formaldehyde tanning is being phased out

Manufacturing and cost

Main manufacturers and suppliers

• Spinneybeck
• Garrett Leather

Trade association: Leather Working Group.

Sources

• Wikipedia: Leather, https://en.wikipedia.org/wiki/Leather
• Spinneybeck: about us, https://www.spinneybeck.com/about-us
• Garrett Leather: leather wallcoverings, https://garrettleather.com/blog/post/leather-wallcoverings
• Wikimedia Commons: Aarong leather wallet.jpg, photo by Nafis Fuad Ayon (CC BY-SA 4.0), https://commons.wikimedia.org/wiki/File:Aarong_leather_wallet.jpg