Grades & Properties of Wood Flooring —
Other Common Names and Related Species:
Western Blue Gum
Karri is one of the tallest tree species in the world — only the California Redwoods are taller. One particular specimen, the "Karri Knight" in Portugal's Vale de Canas National Forest, stands at nearly 260′ (by comparison, the Statue of Liberty is 151′ tall).
Learn more about this hardwood flooring species »
Janka Hardness: 2030
Karri is 57% harder than Red Oak.
Grades of Karri Flooring:
Karri flooring is grouped into two grades. The grades are called different things by different manufacturers, but there is a Select grade Karri and a #1 Common grade. Select grade Karri flooring has some color variation from light tan to pink and grays but has no knots. The #1 Common grade Karri will have pitch pockets and small knots. Pitch pockets are small black openings where pitch gathered inside the tree.
Karri Flooring Dimension Specifications:
Most Karri is milled in Australia because it is more cost-effective to ship finished material than raw lumber. Lengths of the Karri flooring bundles are 7 feet so they can easily fit into 8-foot-wide steel shipping containers. All pre-milled products are tongue-&-groove and end-matched (tongue-&-grooved on the ends of the boards). Moisture content ranges from 6% to 8% for quick acclimation. The average length of the flooring pieces is usually about 3 feet and ranges from 1 to 7 feet. Almost all imported flooring that is found is in 7-foot bundles, with widths available from 2¼″ to 5″. If a long or wide plank floor is desired, raw lumber must be obtained and the flooring must be milled here in the United States. Typically, the lengths can develop up to 12 feet. However, the cost can be double that of the pre-milled stock because of waste and labor costs in the United States. Also, raw lumber is relatively expensive and rare with this species.
Karri flooring is available prefinished or unfinished in solid form for nail-down applications and in engineered form with a veneer top layer for concrete applications. Karri is an uncommon species in comparison with most hardwood flooring. There is a moderate amount of Karri in Australia, and it is not endangered. However, less logging, stricter regulations, and a slower American economy have limited commodities and caused slightly higher prices of this product in this country.
Finished Floor Appearance:
Karri flooring has muted pink, tan, and gray color variations. The pitch pockets are almost black, and the wood color is dark tan and contains dark color variation. Oil- or water-based finishes are recommended. The flooring does not darken significantly with age.
Flooring Durability and Stability:
Karri flooring is very durable and resists denting and traffic wear quite well. It is harder than many North American floors because of its density but can swell with moisture if not acclimated properly. Karri is heavy, weighing about 3 pounds per square foot.
Workability of Karri Flooring:
Although hard and tough, Karri works with little difficulty with both hand and power tools. When installing the flooring, it is best to use a manual nailer, but staples and pneumatic nailers can be used. It holds screws well, glues well, stains, and polishes to a very attractive finish. It can be difficult to sand with flooring equipment, so professional sanding and finishing is recommended. This wood is not very resistant to decay and insects. To avoid a possible allergic reaction to the material, wear a dust mask and long-sleeve shirt when working with Karri.
Principal Uses of Karri Flooring:
Karri flooring is used in medium- to high-end residential and commercial applications for an interesting floor. It is used in rustic camps as well as in contemporary structures.