Tuesday, March 18, 2008

Wood Flooring I

All too often, we over-utilize the phrase "hardwood flooring" without really knowing whether or not we have actual hardwoods. Too simplify this, here are some simple rules to clarify these designations. Hardwoods come from deciduous trees, softwoods come from conifers. Within each of these two categories, there are of course varying degrees of hardness. We know that maple is harder than poplar even though both are considered to be hardwoods.

You also hear people boasting that they have "quarter sawn white oak", but what does this mean? Does this person with this fancy floor even know how that wood was produced? Most often they do not. There are three main methods for getting planks out of a log; flat or plain, quarter and rift sawn. The image below details the way in which flat or plain sawn, quarter sawn, and rift sawn boards are obtained.

We all know the image of a tree's cross section with the rings visible. We learned that by counting the rings, we can tell a tree's age. The rings towards the center of the circle are the oldest and sometimes appear darker than the younger rings towards the outside. The wood from the older rings is referred to as the heartwood, while the wood that is taken from the outer regions is called the sapwood.

Notice how the rings affect how the end grain looks. In flat sawn boards, if we look at the ends, we see the radiating crescents. This is the most common board that we see because it is the most economical way of producing planks. As you can see from the diagram, it yields the least amount of waste. The common problem with wood that is flat sawn is that it tends to "cup" which is when the boards edges curve upward. The wider the board, the more severe the potential cup can be. The reason for this is in the widest of flat sawn boards, you have the youngest wood on the two outside edges pulling against the oldest wood toward the center of the board.

In both rift and quarter sawn boards, the end grain is close to vertical in its relation to the surfaces. This increases the boards stability as well as alters the way the grain is seen on the surface. The boards can be far more beautiful like in the case of the oak mentioned above.

The two examples are both white oak. The upper-most example is quarter sawn. Notice the enhancement of the striations within the grain.

1 comment:

crouchinggreys said...

As usual I learn something new!!! Never knew that about the hardwoods, very interesting!!! Love the floors I think they will have alot of original character when they are finished. Keep up the great work. Can't wait for spring! The pillows for the new couch rock!! Love M