Most people believe that they must use furniture-grade lumber for their woodworking projects. This is not necessarily true. Construction grade lumber can be used as long as you follow a few simple guidelines.
What Is The Difference?
In most areas, kiln-dried construction grade lumber sells for around 70 cents per linear foot. Now that is approximately half the price of furniture grade material, which can greatly reduce the raw material costs of any project.
Most furniture grade lumber is harvested from pine, while most construction grade lumber comes from spruce, jack pine, or fir trees. While these are all considered softwood, they are surprisingly strong and dense.
If you inspect the boards carefully, you will find that most of them can actually be very high quality. It is not unusual to find boards that are nearly free from knots.
Even boards with defects can contain sections of beautiful wood on both sides. Spruce can be particularly attractive when it is quarter-sawn. This reveals its closely spaced growth rings, which have a very striking appearance.
You can produce high-quality furniture from construction-grade lumber as long as you choose your boards carefully and handle them properly. Do not be deterred by minor damage or defects in the wood. You will probably plan and join the wood anyway, so these minor defects can be hidden or worked around.
How Dry Is Kiln-Dried?
When you hear the phrase kiln-dried wood, you would think that you are ready to start your woodworking project, but do not be fooled. For construction grade lumber the term kiln-dried means that the wood has less than 20% moisture.
While this level of moisture is low enough to prevent the growth of mold, it is still too moist to be used for furniture building immediately.
The optimum moisture content for furniture building is actually between 6% and 8%, so the lumber will need to be dried further before it can be used effectively.
The extra drying can be done once you get the wood home, but before you leave the lumber yard, ask about taking some of the thin wood strips that are used to separate boards within the stacked piles. These will usually be free, as the lumber yard will throw them out anyway.
Performing the Extra Drying
Once you get the wood home, re-stack the boards using the thin spacers you picked up at the lumber yard. It is extremely important each board has the maximum amount of surface area exposed to air.
You will need to stack the wood in a fully heated, indoor environment. The best time of year to do this is during the winter months, as the humidity will be the lowest.
To speed up the drying process, place an oscillating fan blowing on the pile. This will reduce the moisture content from 20% to 8% in about a month.
Now, this does not mean that you need to wait this long before working with the lumber. You can measure and cut the lumber for your project, just make sure that you do not plan, join, or assembly the pieces until reaching the 8% moisture level.
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