All About Lumber

When it comes to choosing the right type of wood for various projects, whether you're building a bookshelf, crafting a table, or even constructing a backyard deck, knowing how to navigate lumber dimensions and understanding the differences between hardwood and softwood ensures you get the right materials for your project. Let's delve into lumber measurements, explain common terms, and provide tips for choosing the right lumber for your needs.

Let's start with common lumber dimensions

Lumber dimensions can be a bit confusing because they usually don't match the size advertised. Here are the key terms and what they actually mean:

  • Nominal Dimensions: This is the size used to advertise the lumber, but it's not the actual size of the wood in your hand. The lumber is cut to these sizes and then is processed to make the smooth boards in the store. For example, a piece of lumber starts as "2x4" is not actually 2 inches thick by 4 inches wide by the time it gets to you.
  • Actual Dimensions: This refers to the real dimensions of the wood once it's been planed and dried. Using the "2x4" example, the actual size would be 1.5 inches thick by 3.5 inches wide. In most cases, the difference is 1/2 of an inch but sometimes it's as small as 1/4 of an inch (like in the case of lumber with a nominal thickness of 1 inch.)
  • Linear Feet: This is purely the length of the board and is usually how the cost of the lumber is presented. For example $3.76 / linear feet. You may see "R/L" on the tag in the store, which stands for "Random Length" and indicates pricing per linear foot. (Many newbies are caught off guard by this, thinking a whole 8ft board is just $3.76 and when they get to the checkout it's $30.08.)
  • Board Feet: Actually a measure of volume and so is LxWxD. Some places price lumber this way, but this author has never seen it in person.

The difference between nominal and actual is due to milling and drying. The milling process removes the rough, uneven edges and produces the smooth edges you see in the store; see diagram below. The milling process does not impact length so that means the nominal length and the actual length usually match.

So what's the deal with "softwood"? Isn't all wood hard?

Yes and no. In fact, hardwoods aren't necessarily "harder" than softwoods. The terms technically refer to the type of tree the wood comes from.

  • Hardwoods: These come from deciduous trees that lose their leaves annually. Examples include oak, maple, cherry, and walnut. Hardwoods are generally slower-growing and denser, which often makes them more durable and resistant to wear.
  • Softwoods: Softwoods, on the other hand, originate from evergreen coniferous trees that bear cones and needles year-round. Pine, cedar, spruce, and fir are common examples. Despite being called "soft," some softwoods like pine can actually be quite hard.

Here's a handy chart to help you compare the two types to make the right choice for your project:

Tips for Choosing Lumber

  • Plan your project and add extra: Everyone makes mistakes so when calculating how much lumber you need, add some extra.
  • Check for defects: Check each piece of lumber for defects such as knots, splits, or warping. These can affect the strength and appearance of your finished project. This is especially crucial if you are shopping at a large home improvement store where you see a higher level of damage, warping, and attempts to patch imperfections (see photo below). We recommend finding your local lumberyard for better quality and better prices.
  • Consider intended use: How durable does this need to be? Is the grain going to show or will it be painted? For example, you don't need to spring for curly maple or purple heart if you're going to paint over it. (You will also make us cry if you do that because those are beautiful woods and should be on display!)
  • Think about cost and availability: Are you working on a large project over a longer time? If so, you want to make sure your chosen lumber will be available when you need more. Pine and Poplar tend to be consistently easy to find in high volumes, for example.

Still with me? Let's wrap it up!

Understanding lumber measurements and characteristics is essential for anyone involved in woodworking or DIY projects. By knowing the difference between nominal and actual sizes, understanding pros and cons of hardwoods and softwoods, and selecting the right type of lumber, you can ensure your projects are both structurally sound and visually appealing. Take the time to familiarize yourself with these concepts before starting your next woodworking adventure. With this knowledge in hand, you'll be well-equipped to tackle any project with confidence. Happy building!

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