Is Oak a Hardwood or a Softwood? (& Is It Strong?)

Is Oak a Hardwood or a Softwood? (& Is It Strong?)

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If you are wondering how strong of a wood oak is, you’ve come to the right place. Today, we’re going to talk about whether oak is a hardwood or softwood, and we’ll take a look at some important factors to determine how strong it is.

Is Oak a Hardwood or Softwood?

Oak is a hardwood, is moderate to very hard, and can be found all throughout North America and in many other places in the world.

Oak Wood Strength: All You Need to Know

Today, we want to take a closer look at exactly how strong oak wood is, and to do this, will be examining it based on five main factors. These include compressive strength, bending strength, stiffness, hardness, and density. Do keep in mind that there are very many different types of oak out there, so we will be comparing the different types with each other.

Compressive Strength

Let’s take a look at what the compressive strength of these different types of oak is like:

  • Red Oak – 6,780 lbf per square inch (46.8 MPa)
  • White Oak – 7,370 lbf per square inch (50.8 MPa)
  • Bur Oak – 5,890 lbf per square inch (40.6 MPa)
  • Black Oak – 6,450 lbf per square inch (44.5 MPa)
  • California Black Oak – 5,640 lbf per square inch (38.9MPa)
  • Swamp Chestnut Oak – 7,200 lbf per square inch (49.6MPa)
  • Willow Oak – 7,040 lbf per square inch (48.6MPa)
  • Water Oak – 6,770 lbf per square inch (46.7 MPa)
  • Swamp White Oak – 8,400 lbf per square inch (13.99 MPa)
  • Laurel Oak – 6,980lbf per square inch (48.1 MPa)
  • Overcup Oak – 6,200 lbf per square inch (42.8 MPa)
  • Chestnut Oak – 6,830 lbf per square inch (47.1MPa)
  • Post Oak – 6,530 lbf per square inch (45.1 MPa)
  • Scarlet Oak – 8,250 lbf per square inch (56.9 MPa)
  • Cherrybark Oak – 8,740 lbf per square inch (60.3 MPa)
  • Live Oak – 8,810 lbf per square inch (60.8 MPa)

Live oak is the strongest of all oak types in terms of compressive strength, followed by cherrybark and swamp white oak. As far as hardwoods go, most types of oak are moderate to very strong in terms of compressive strength.

In case you don’t know what compressive strength is, this may also be referred to as the crushing strength of wood. This refers to how much weight a piece of wood can take parallel to the grain. As an easy-to-visualize example, imagine a table with four legs. How much weight can you put on that table before the four vertical legs start to buckle and eventually break?

Bending Strength

Let’s take a look at what the bending strength of the different types of oak is like:

  • Red Oak – 14,380 lbf per square inch (99.2 MPa)
  • White Oak – 14,830 lbf per square inch (102.3 MPa)
  • Bur Oak – 10,920 lbf per square inch (75.3 MPa)
  • Black Oak – 14,430 lbf per square inch (99.5 MPa)
  • California Black Oak – 8,610 lbf per square inch (59.9 MPa)
  • Swamp Chestnut Oak – 13,760lbf per square inch (94.9 MPa)
  • Willow Oak – 14,860 lbf per square inch (102.4 MPa)
  • Water Oak – 16,620 lbf per square inch (114.6 MPa)
  • Swamp White Oak – 17,400lbf per square inch (120 MPa)
  • Laurel Oak – 14,330 lbf per square inch (98.8 MPa)
  • Overcup Oak – 12,600 lbf per square inch (86.9 MPa)
  • Chestnut Oak – 13,300 lbf per square inch (91.7 MPa)
  • Post Oak – 13,070 lbf per square inch (90.1 MPa)
  • Scarlet Oak – 16,080 lbf per square inch (110.9 MPa)
  • Cherrybark Oak – 18,100 lbf per square inch (124.8 MPa)
  • Live Oak – 18,220 lbf per square inch (125.6 MPa)

In terms of bending strength, live oak is the strongest, followed by cherrybark and swamp white. In terms of bending strength in comparison to all types of hardwood, oak is up there with the best of them.

If we are talking about the bending strength, this may also be referred to as the modulus of rupture. The modulus of rupture is all about how much weight a piece of wood can take perpendicular to the grain. For example, if you were to hang a stick horizontally on a wall, and then hang a bucket off of the end of it, how much water could you put into that bucket before the stick breaks in half?

Stiffness

Let’s take a look at how stiff the different types of oak are:

  • Red Oak – 1,761,000 lbf per square inch (12.14 GPa)
  • White Oak – 1,762,000 lbf per square inch (12.15 GPa)
  • Bur Oak – 1,040,000 lbf per square inch (7.17 GPa)
  • Black Oak –  1,736,000 lbf per square inch (11.97 GPa)
  • California Black Oak – 980,000 lbf per square inch (6.76 GPa)
  • Swamp Chestnut Oak – 1,753,000 lbf per square inch (12.09 GPa)
  • Willow Oak – 1,804,000 lbf per square inch (12.44 GPa)
  • Water Oak – 2,034,000 lbf per square inch (14.02 GPa)
  • Swamp White Oak – 2,029,000 lbf per square inch (13.99 GPa)
  • Laurel Oak – 1,793,000 lbf per square inch (12.37 GPa)
  • Overcup Oak –1,420,000 lbf per square inch (9.80 GPa)
  • Chestnut Oak – 1,590,000 lbf per square inch (11.0 GPa)
  • Post Oak – 1,495,000 lbf per square inch (10.31 GPa)
  • Scarlet Oak – 1,766,000 lbf per square inch (12.18 GPa)
  • Cherrybark Oak – 2,280,000 lbf per square inch (15.7 GPa)
  • Live Oak – 1,960,000 lbf per square inch (13.52 GPa)

The stiffest types of oak on the list today are cherrybark oak, swamp white oak, and water oak. In comparison to other types of hardwood, oak is fairly moderate on this front.

If you need to know what the stiffness of wood is, this is also called the modulus of elasticity. This is in reference to how much weight a piece of wood can hold before it begins to bend. As an example, imagine yourself standing on a 2×4” that is being supported by a brick on either side. How much weight do you have to place on the middle of that board before it begins to sag?

Hardness

Let’s take a closer look at how hard the different types of oak are:

  • Red Oak – 1,220 lbf
  • White Oak – 1,350 lbf
  • Bur Oak – 1,360 lbf
  • Black Oak – 1,210 lbf
  • California Black Oak – 1,090 lbf
  • Swamp Chestnut Oak – 1,230 lbf
  • Willow Oak – 1,460 lbf
  • Water Oak – 1,190 lbf
  • Swamp White Oak – 1,600 lbf
  • Laurel Oak – 1,210 lbf
  • Overcup Oak – 1,190 lbf
  • Chestnut Oak – 1,130 lbf
  •  Post Oak – 1,350 lbf
  • Scarlet Oak – 1,400 lbf
  • Cherrybark Oak – 1,480 lbf
  • Live Oak – 2,680 lbf

Live oak is by far the hardest of all varieties, followed by swamp white oak. As far as hardness across the board is concerned when compared to other types of hardwood, oak is moderate to very strong.

If we are talking about hardness, this refers to how hard the outer surface is, or in other words, how well it can resist physical damage such as denting and scratching. This is generally measured on the Janka hardness scale.

Density

Let’s take a closer look at how dense the different types of oak are:

  • Red Oak – 43 lbs per cubic foot (700 kilograms per cubic meter)
  • White Oak – 47 lbs per cubic foot (755 kilograms per cubic meter)
  • Bur Oak – 45 lbs per cubic foot (725 kilograms per cubic meter)
  • Black Oak – 45 lbs per cubic foot (725 kilograms per cubic meter)
  • California Black Oak – 39 lbs per cubic foot (620 kilograms per cubic meter)
  • Swamp Chestnut Oak – 49 lbs per cubic foot (780 kilograms per cubic meter)
  • Willow Oak – 48 lbs per cubic foot (770 kilograms per cubic meter)
  • Water Oak – 45 lbs per cubic foot (725 kilograms per cubic meter)
  • Swamp White Oak – 48 lbs per cubic foot (765 kilograms per cubic meter)
  • Laurel Oak – 46 lbs per cubic foot (740 kilograms per cubic meter)
  • Overcup Oak – 47 lbs per cubic foot (760 kilograms per cubic meter)
  • Chestnut Oak – 47 lbs per cubic foot (760 kilograms per cubic meter)
  • Post Oak – 47 lbs per cubic foot (760 kilograms per cubic meter)
  •  Scarlet Oak – 46 lbs per cubic foot (740 kilograms per cubic meter)
  • Cherrybark Oak – 49 lbs per cubic foot (785 kilograms per cubic meter)
  • Live Oak – 63 lbs per cubic foot (1,000 kilograms per cubic meter)

Oak is one of the heavier types of hardwood in general, with live oak being the heaviest of all.

If you don’t know what the density is, this refers to how heavy a piece of wood is in regard to a specific size or area, which is usually measured in pounds per cubic foot or kilograms per cubic meter. Knowing the weight of wood is important, as it tells you about its durability and how easy it is to work with.

Is Oak Strong?

As far as different species of hardwood go, oak is moderate to very strong, and it is stronger than virtually all types of softwood.

Summary

Now that you know exactly how strong oak is, you can make an informed decision as to whether or not this is a type of wood that you would like to use for future projects.