Asked by: Adair Tembrockhausasked in category: General Last Updated: 9th January, 2020
Why is lumber measured in quarters?
In this way, why is wood measured in quarters?
Rob Johnstone: The “quarter system” is a metric for roughsawn lumber. It simply refers to how many 1/4-inches thick the rough stock is. For example, 4/4 (read out loud as four-quarters) is 1-in. thick in the rough.
One may also ask, is a 4x4 really 4 inches? Believe it or not, there actually is some rhyme and reason for why the actual measurements of dimensional lumber don't match their names.
Actual Dimensions and Nominal Dimensions.
|Nominal Measurement||Actual (inches)||Actual (mm)|
|2 x 12||1-1/2 x 11-1/4||38 x 286|
|4 x 4||3-1/2 x 3-1/2||89 x 89|
|4 x 6||3-1/2 x 5-1/2||89 x 140|
One may also ask, why is a 2x4 not 2 inches by 4 inches?
"Dimensional" lumber is the general name for framing lumber. Now, most timber is milled and planed to give it a little more of a finished look, and a little more of a consistent size and profile. Because of this extra milling, a 2x4 no longer measures a full 2 inches by four inches.
What size is 4/4 lumber?
Also in North America, hardwood lumber is commonly sold in a "quarter" system, when referring to thickness; 4/4 (four quarter) refers to a 1-inch-thick (25 mm) board, 8/4 (eight quarter) is a 2-inch-thick (51 mm) board, etc.