What Is Rough Sawn, Full-Dimensional Lumber?

To understand rough-sawn and full-dimensional lumber, it’s important to understand the different ways that lumber might get processed before it gets sold. All lumber gets cut to the specified dimensions, but almost all methods of drying and processing will shrink the boards to some degree. Woodworkers need to be aware that the source and processing method of their lumber will impact the actual dimensions of the boards.

Rough Sawn And Full-Dimensional Lumber

Depending on a variety of factors including lumber type, lumberyards will cut timber to various sizes and leave them out in the air to dry. Once it dries, the lumber will not all be the same uniformed size, even if they are close. This is called rough-sawn lumber. It might still contain up to 20 percent water. If this is the case, the boards will still be close to the dimensions that it had when it was cut.

This is why it is called full-dimensional lumber. An air-dried two-by-four still measures very close to two inches by four inches. This is because air drying leaves quite a bit more water in the wood than modern, commercial drying processes, such as in a kiln or dryer. The water expands the wood.

Typical Lumber From The Lumber Yard

These days, woodworkers and carpenters tend to purchase lumber from retail sources. These retail wood sources include home improvement stores and even big box stores. This mass-produced wood comes in bundles and gets dried in commercial kilns before it gets packaged up and sold at retail outlets.

The kilns remove more water than air drying does. Because much of the moisture is pulled out of the material, it will cause the wood to shrink. A common 2 by 4 is really about 1.5 by 3.5 inches. After the wood loses most of its water, it goes down in size.

The Advantages Of Rough-Sawn Lumber

Air-dried lumber can be purchased at certain lumber yards and companies that deal with a variety of hardwoods and softwoods. It is difficult to find it at a warehouse though such as Lowe’s and Home Depot.  You typically will have to go to a mill that cuts the wood themselves to locate material of this kind.

Some woodworkers and carpenters prefer it because of these advantages:

* Various wood types for a variety of furniture and woodworking are only rough sawn.

* The surfaces can have a more rustic appearance, since they aren’t milled like what you see in the lumber store.

* This wood stock can be produced with less environmental impact because they are simply air dried.

* Typically, the more exotic woods with rich colors and designs are only rough sawn.

Since the lumber is usually available from local producers, some woodworkers also like to purchase rough-sawn lumber because it helps support local businesses and companies. Lumber from large chains may have been transported from across the country or even from another country. Transportation costs also add to the environmental impact of mass-produced lumber.

Rough-Sawn Lumber Disadvantages

The main disadvantage of rough-sawn wood stock is that it takes more effort to work with it. Woodworkers are normally the ones that will employ and purchase this type of material. You have to mill it including planning and possibly running it on a jointer, depending on if you purchase the wood true on one side.

Another problem is purchasing it before it is completely dry. The lumber mill should tell you if it needs to sit up, stacked with sticks between them so that they can dry for a longer period. If this is the case, you aren’t able to work with the material right away, but have to wait for the moisture to air out.

Some woodworkers prefer the more naturally processed lumber for almost all uses. However, it might be an issue if you are strapped for time, or lack the tools needed in order to mill it to the proper size.

 

About The Author:

Ted Leger is a woodworking enthusiast who turned his hobby into a passion. You can find more woodworking tips and advice from him at his woodworking blog, http://www.WooDesigner.net

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