Lumber, which is sawn wood, is still the construction material of choice in the United States and many other countries. However, not all wood is best for all kinds of construction. Here are some tips to choose the best lumber for a construction project:
Hardwood vs. Softwood Lumber
Lumber can be made from hardwood trees or softwood trees. Hardwood trees are usually deciduous trees such as oak or maple while softwoods are usually conifers such as pine or cedar. Hardwood and softwood doesn’t necessarily tell the builder whether the wood is hard or soft. Balsa wood is one of the softest woods known yet is classified as a hardwood. But it is true that most softwood used in construction is indeed a bit softer than hardwood.
Softwood is preferred for construction by builders because it’s less expensive than hardwood. This is because softwood trees grow more quickly and are ready for harvest earlier than hardwoods. Softwood lumber is abundant at building supply stores.
How to Buy Softwood Lumber
In the United States, softwood lumber is rated by the American Softwood Lumber Standard. The classifications are Shop and Factory, Yard and Structural.
Shop and factory is used in doors, ladders, boxes and other items that are not meant to support a great weight. Because shop lumber can be used for so many different things, including clothespins, each type has a different grading system.
Yard is made for building construction. They are graded by eye then separated into the common and select categories. These categories are broken down still further. No 1. common is the highest quality, followed by No. 2 and No. 3. These grades are based on the number and sizes of knots found in the wood. The professionals at the local building supply store can help the builder choose the right wood for their construction project.
Select yard lumber ideally has no knots. If it does have knots, they are very small and few in number. This type of wood is used for finishes and is graded by letter. C select is nearly flawless, and D select is allowed to have a few tiny knots.
Structural lumber is cut to standard widths and thicknesses, such as 2 x 4. Because these pieces are used to make the frames of houses, they’re usually machine stress graded then separated into seven more categories. They are:
Light framing, which is the standard 2 x 4. Lumber used for light framing can be construction grade, which means they are allowed small knots; standard, which can have small splits at the ends and a few knots; utility, which can have longer splits and any number of knots.
Structural light framing is 2 to 4 inches wide or 2 to 4 inches thick. These pieces of lumber can be graded as select structural, which means they are free of knots or only have one or two tiny knots. Nos. 1, 2 and 3 can have knots of a certain size and number.
Other structural lumber is studs, structural joists and planks, beams and stringers, posts and timbers and appearance framing. These pieces that can be found in any building supply store are different widths and thicknesses.
Besides this, there is a different grading category of Douglass and Hem firs. These are supreme, choice and quality. Yet another grading system, A, B, C and D is applied to other softwoods that are harvested in the west. Again, they are graded according to the number of knots and blemishes.
The builder should also know the moisture content at the time that the lumber was manufactured, or surfaced. This needs to be known because softwood absorbs more water than hardwood, and it shrinks as it dries out, which can affect the construction.
Finally, the would-be builder who goes to their building supply shop for a construction project should look for a stamp on the wood they wish to use. It will tell them the grades, how dry the wood is and the type of tree it came from.
Lumber Pressure Treatment
Because softwood absorbs water faster than hardwood, it is at higher risk for rotting, especially if it is exposed to the weather. To combat this, softwood is often pressure treated. In the past, it was usually pressure treated with chromate copper arsenate, or CCA which gave it a greenish tint. The greenish tint came from arsenic, which is a carcinogen. Now lumber is pressure treated with copper compounds. It still has a green tint to it which the buyer will see when they go to their building supply store.
If your company is looking for construction materials in Oklahoma, contact Security Building Services and Building Supply Tulsa today! Call us at (918) 663-6272 to speak to a qualified lumber expert.
Fore more information on construction materials and building supply in Tulsa, please follow the Security Building Services and Supply blog. You can also find Security Building Services and Building Supply on Facebook.
Commonly Used Construction Materials and Their Uses – Building Supply of Tulsa
There are many different types of building materials involved in constructing a house or building. Learn more about construction materials and building supplies with Security Building Service and Supply of Tulsa.