nominal vs actual, wet vs dry

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Old timber measured actual dimensions like 2x4, 2x6 and was often unplaned. Modern lumber is referred to as nominal dimension. A 2x4 is actually about 1-1/2 x 3-1/2. 6-inch is 5-1/2 inch wide and so on. So you bought 1-1/2 x 13-1/2 lumber, or 2x14 nominal. Just about the only thing on the market.

Acclimating wood to the house is a good question, and it depends on whether you bought kiln dried lumber or green. Most lumber sold by Home Depot is softwood and is not kiln dried. You can tell right away. Kiln or stick dried lumber will be less than 15% moisture from the mill and may actually increase due to humidity depending on local conditions where it is stored. The kiln dried lumber does not need acclimating and is very stable with regard to warp. Look for a stamp S-Dry or KD or KDAT (kiln dry) and sometimes HT (heat treated).

Green lumber (S-Grn) on the other hand may contain more than the weight of dry wood in moisture. By definition it is greater than 19% from the mill, but may have 50% to 75% moisture, and sometimes free moisture is evident between the boards or emerges when you drive nails. Air drying takes up to 270 days, but will be much less in a heated environment. If you are storing this in your conditioned living space figure on 60 days. Get a moisture meter ($100) and check for less than 20% moisture content before using.

To air-dry lumber stack the lumber in layers separated by narrow strips of wood, or stickers. to allow air to move freely between layers. Align the stickers vertically within the pile. Alignment helps to distribute the load evenly to minimize warping during drying. Also, it’s a good idea to place weights, such as concrete blocks. on top of the pile to help minimize twising of lumber during dying. (Avoid iron weights because they can stain the wood if they get wet.) If the pile is protected from the weather–either by a shed or by plastic sheeting–and is allowed to dry several weeks. the lumber should reach a moisture content of close to 20%.

Its a false economy to buy cheap wet wood.