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Lumber 101 and Moisture Meters

Today we're discussing the language of lumber.  This blog is pertaining to lumber for furniture. If you're new to the woodworking or crafting field you may have recently started to hear terms like four quarter and moisture content. You may be wondering, what are they talking about? Hopefully this quick guide will help you make some sense of these new terms.

The Lumber Lingo!

Knowing the lingo will make your life a whole lot easier when purchasing lumber from an ad or at a lumber yard. Here are a few commonly used terms and meanings.

The thickness of lumber is referred to in quarters (1/4 inches), for example if someone says four quarter (4/4) that means one inch thick. Six quarter (6/4) means 1.5 inches thick, eight quarter (8/4) means 2 inch thick, and so on. Most lumber sold outside of a box store is going to be sold in board foot or linear foot. Board foot is based on the overall volume of the lumber, so to get the board foot you take; length x width x thickness, & divide by 144. Example a 4/4 board that is 8 inches wide by 8 feet long has 5.33 bd.ft.  Linear foot is simply the length of the material. This is popular when referring to hardwood flooring or shiplap.

If your wood is stamped KD and HT this means kiln dread and heat treated. If your interested in more detail on this topic CLICK HERE. They have tons of great information! 

Lumber Abbreviations

BF                Board feet

Com            Common

E                  Edge

KD               Kiln Dried

HT               Heat Treated

RGH            Rough

RL               Random lengths

RW              Random widths

S1S             Surfaced one side

S2S             Surfaced two sides

S4S             Surfaced four sides

Different cuts of lumber

      There are several different ways to process lumber, which simply means the way it is cut into boards. Does it matter what kind of cut I get? It all depends on what you intend on using your lumber for, odds are most lumber you have access to will be flat sawn lumber. This is the most common way to process lumber and this is what you will find at all big box stores. It is the cheapest way to process lumber. Quarter sawn lumber is more expensive to process and less likely to warp, cup, or twist because of the direction of the grain running though the board. This also gives it a unique look. Most likely you will find flat sawn lumber because it is the most abundant and affordable. For most of your woodworking needs quarter saw or rift sawn lumber isn't really necessary as it is primarily used in high end furniture because of its resistnance to movement along with its desired grain pattern.


Moisture Content and your lumber.

Moisture in my lumber? Understanding moisture is extremely import if you want to build quality furniture that will last. We have learned this the hard way by not checking moisture and having to fix the issue months down the road when the seasons change and your piece changes right along with it! Prevent this from happening by understanding the basics before you build. 

The moisture content of the lumber is what determines whether it will expand or contract. Most lumber that you are able to purchase from a store or lumber yard will be kiln dried, which is a process that removes most of the moisture from when the tree was alive by placing the green lumber into a kiln and circulating hot air.  When using lumber for furniture you want between 7% and 11% moisture. This range will likely give you the least amount of movement in the wood. As the lumber dries, the wood itself actually shrinks which is what can cause cupping, bowing, or twisting. Have you ever purchased "straight" lumber from a big box store just to find it a few weeks later to be all twisted and bowed? This is because the wood might not have been properly kiln dried or the wood is now being stored in an area that has a lot higher humidity than where it was previously stored. Moisture content and wood movement go hand in hand and is a key factor in being successful at woodworking.

Both of these topics will be explored more in later blogs as there is tons of information revolving around each! Be sure to check out the link below for even more information!
CLICK HERE         



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  • Hey Rhianna,
    Thanks for checking out our blog! The article above is strictly pertaining to lumber used for furniture. Quarter sawn lumber is very pricey and wouldn’t be necessary for a tree house, its mostly used in fine furniture. I would recommend some treated lumber from a big box store like home depot which is designed to be outdoors and used for constructing homes and tree houses. If you have any questions feel free to send us an email.

    • Two Moose Design
  • I’m going to a lumber yard this weekend to get some lumber for a treehouse that I’m building for my kids, and I really appreciate you breaking down the terminology for me. Because Quarter sawn is less likely to warp, that’s probably the cut that I’ll want to get for my kids’ treehouse for the maximum stability. I’ll also probably take your advice and get 7-11% wood moisture so that it doesn’t bow or twist, though I don’t know how it being in a tree could affect that, so I’ll talk to the lumber yard, just to be certain.

    • Rhianna Hawk