Are there different grades of lumber? If so, what are they?

Question answered Via Quora.

Answer:

Mike Capuzzo, Woodland Custom Beam Company

There are indeed different grades of wood. First you have the four major woodwork-able grades of hardwood. There are grades under the 4 top tiers, but the lower grades aren’t really reliable for any types of wood work. The tiers for hardwood are:

First and Seconds
Select
#1 Common
#2 Common

These woods are graded based off of the number of defects per a given length. for grading standards to be met, the wood must meet a minimum lumber size with a minimum percent of use-able face. The grading statistics followed in the above order are:

8 Feet by 6 Inches at 83% Face
6 Feet by 4 Inches at 83% Face
4 Feet by 3 Inches at 66% Face
4 Feet by 3 Inches at 50% Face

There are also different grades of soft wood. Soft woods are based off of grade and appearance, and are most commonly used in the woodwork industry such as creating Exposed California Box Beams. The 4 major tiers of soft wood are:

C Select
D Select
1 Common
2 Common

Soft woods are graded by far more agencies than hardwoods, and therefore have some variation in terminology of grading, but are based off of the following in the order of the above: