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  • Douglas Fir Hardwood Q&A

    Posted on December 18, 2012 by Jennifer

    You’ve got questions about Douglas fir flooring? Great! We’ve got answers. Read on to learn all you ever wanted to know about hardwoods, softwoods, hardness ratings, and what all those terms really mean for the lifespan of your hardwood flooring.

    Q: Is Douglas fir a hardwood?

    A: That depends on what you mean when you say hardwood. Actually, “hardwood” and “softwood” are generic terms that have nothing to do with the physical hardness of the wood. “Hardwood” is a common term for a broad class of trees scientifically known as angiosperms. Angiosperm means “enclosed seed,” and it refers to plants whose mature seed is in some sort of fruit or nut. Oak, cherry, walnut—these are all angiosperms, or hardwood trees.

    “Softwood” is the common term for gymnosperm plants. Gymnosperm means naked seed. These plants usually carry their seeds in some kind of cone, which opens to expose the seeds once they are ripe. Pines, firs, cedars—these are gymnosperms, or softwood trees.

    Douglas fir falls in the gymnosperm, or softwood category. So is it a hardwood? Technically no. However, if what you’re really asking is whether or not Douglas fir is a tough, strong building material, the answer is yes—it’s widely known as a very durable wood.

     

    Q: So which is harder – hardwoods (angiosperms)? Or softwoods (gymnosperms)?

    A: It varies from tree to tree. Oak, Ash and Walnut are all very hard angiosperms. However, Douglas fir, which is a gymnosperm, or softwood, is actually harder than chestnut, an angiosperm that most people would call a hardwood. Balsa is a hardwood, but its wood is so soft and lightweight that it’s most commonly used for making model airplanes.

     

    Q: Then how can I tell which woods are the hardest? How do they measure this stuff, anyway?

    A: Engineers use a lot of different factors when they are determining the strength of a material, and hardness is only one of them. “Hardness” is defined specifically as “resistance to indentation.” Scientists test for this via the Janka hardness test. They take a .444-inch steel ball and drop it repeatedly onto the surface of a plank. The amount of force it takes to embed this little ball halfway into the plank gives the wood its Janka hardness rating. Douglas fir gets a Janka hardness rating of 660 pounds-force.

     

    Q: Then woods with the highest Janka hardness ratings are the strongest?

    A: Nope. Like we said before, there are many different factors that engineers and materials scientists consider when they are determining the strength of a material. Other factors to consider are modulus of elasticity, which measures how well a material can bend and still return to its original shape without deforming or breaking: Impact bending, which is measured by dropping a hammer on a beam from higher and higher heights until the wood either snaps or deflects 6 inches or more; and tensile strength, which is how much force a material can handle without breaking when it’s stretched.

    Douglas fir has a relatively low Janka hardness rating, but it has a high modulus of elasticity as well has high ratings for shear, tension parallel-to-grain, compression, and other strength characteristics. In fact, Douglas fir’s strength-to-weight ratio is so superiorthat it is considered the material of choice for most commercial and residential building projects in North America.

     

    Q: What about my floors? Is Douglas fir hard enough to use for flooring?

    A: Absolutely. Unless you are shooting steel balls into your floors on a regular basis, you should have no problems with the durability of your Douglas fir flooring. The Pacific Northwest is full of homes dating from the early part of the 20th century whose original Douglas fir floors are still beautiful—80 to 100 years after they were first installed. Yes, scratches and dents are possible, but they’re a possibility on any flooring, even hardwoods like oak or man-made products like ceramic tile. Make sure your Douglas fir floor has a quality finish, keep the floors clean with sweeping and occasional mopping, and maintain the finish when necessary.

    If you can do those simple things, your Douglas fir flooring will last a lifetime, with durability that ranks up there with any so-called “hardwood” on the market.



    This post was posted in Douglas Fir Flooring and was tagged with Douglas fir flooring, janka hardness, douglas fir hardwood q&a, hardwoods, softwoods, angiosperms, gymnosperms

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