What is the real size of a 2x4?Nominal vs. Actual.
The 2x4 is the most well-known piece of lumber.It is mostly used in the framing of houses, but you will also see it in any other construction project.
A 2x4 is not really two inches by four inches as the name implies.A 2x4 is actually close to 1 inch.Many of you know this, but why is it?If you go to Subway and pay $5 for a long, you don't expect to get 11 inches.It is not just a 2x4: a 1x4 is actually 34 inches by 3-12 inches.This is how it has always been for most of us.
There is a reason.The discrepancy in size is due to the need for the lumber industry to stay competitive during times of scarcity.
Before mass production of lumber and wood started around 1870, trees were cut and made to order for carpenters.It was up to the builders on site to make final sizes.Many people in the industry viewed lumber and forests as an unlimited resource, because trees were grown and used locally.
As the population grew in the United States, so did building.The once unlimited resources were starting to be hard to find.Major U.S. cities like New York, Boston, Baltimore, and Philadelphia were where the prime forestland was located.The forests around these cities were becoming clear.
Other areas of the country saw this as an opportunity to enter the market as resources in these areas became scarce.The railroads made it possible for other cities to ship lumber to different parts of the country.The lumber capitals of the country were Chicago, Albany, NY, and Bangor, ME.
There was competition among regions and species.For example, western Douglas fir and western hemlock forests competed against southern yellow pine forests.
The purchaser of lumber was responsible for shipping at the turn of the 20th century.The cost of lumber doubled when shipping charges were determined by distance traveled and weight, according to the U.S. Department of Agriculture.The impact of wood on economics began to change.Thinner, lighter sizes were preferred by people in the industry.Optimal finished sizes of preferred species were produced by kiln drying.
The same technology used to power steam engine trains was being used in the new circular saw to achieve faster, continuous cuts.The evolution of framing building was related to this development.The wood was shipped directly to the job site.The 2x4 was being used more and more.
The need for a uniformed sizing became apparent with the increased use of common lumber.Trade associations were formed as retail lumberyards pushed for more regulation.The attendees of the first American Lumber Congress called for size and terminology standardization.For decades, there was disagreement about specific language.
Then came World War II.There was a shortage of wood for the lumber industry because of the war demand.Builders began to use concrete block and engineered products instead of wood.There was a lot of pressure to figure out how to become more efficient in the forest industry.Thinner 2x4s were a way to compete with alternatives in the industry because of the lack of resources.
Size standards, maximum moisture content, and naming were all agreed upon in 1964.The nominal 2x4 became the actual board.The industry was able to sell 2x4s with 34% less volume at a lower price than alternatives.The standard is accepted in the building industry.
The standard was challenged by lawsuits against Home Depot and Menards.Both claims were dismissed by a judge.
Next time you go to your local lumber store and order a few 2x4s, take a moment to think about the actual dimensions you are getting.You know this is how it has always been, but now you know why.
There is a link to more information on our website if you want to know common lumber dimensions.