When it comes to wood flooring, the wood used is graded by the manufacturers according to its appearance. We have recently covered the topic of grades in wood flooring, but felt it deserved a further write-up. Generally speaking, the features taken into account when grading wood include (but are not limited to): the number and size of knots; the amount of sap present in the wood and its colour variations. As a rule of thumb, the smaller the knots, the lower the sap content and the more uniform the colour, the higher the grade of wood and (of course) the higher the price.
When it comes to deciding which wood grade is best for your wooden flooring, there are four grades of wood to choose from. Each grade gives a slightly different look. The grades are called:
1. Prime or AB
2. Select or ABC
3. Natural or ABCD
4. and Rustic or CD
In order to help you make the choice of wood grading for your hardwood flooring here are some of the characteristics of each grade:
Prime Grade

Prime Grade
Prime Grade is the highest grade of wood flooring. It is also often described as AB-high grade. Cut from the centre of the log, this grade of wood is uniform in its appearance and has very few knots. If this quality of wood grade does contain knots, they tend to be small and unobtrusive. Furthermore the sap content of this wood is very low. Finally, and often one of the most important considerations for people choosing a wood grade, the colour variation is minimal, but still there, due to the fact that wood is a natural product. A Prime grade floor will have a very uniformed look.
Select Grade

Select Grade
Select Grade is the next grade of wood flooring. Often described as ABC grade, this wood contains some knots, but less than Natural grade, some sap and some colour variation.
Natural Grade

Natural Grade
Natural grade comes next on the wood grading ladder. Often referred to as mill run or ABCD grade, this wood grade sports knots of bigger size than Select, further more it contains sap and has more colour variation. Certain manufacturers use a coloured wood filler to fill any holes which are naturally present in the wood, resulting in a smooth overall look.
Rustic Grade

Rustic Grade
Rustic Grade is the final grade for wood flooring. As the name suggests, it will display a larger range of colour variation, sap and will have more knots and fillers, giving it a very nice, traditional vintage look.
Comparing the Four Wood Flooring Grades
Grade | Description | Knots | Sap Content | Colour Variation |
---|---|---|---|---|
Prime or AB | Highest grade with uniform appearance and very few small knots | Very few, small and unobtrusive knots | Very low | Minimal, but still present |
Select or ABC | Contains some knots, but fewer than Natural grade. Some sap and some colour variation | Some knots | Some sap | Some variation |
Natural or ABCD | Sports bigger knots compared to Select grade, contains sap and has more colour variation. Some manufacturers use wood filler to create a smooth overall look | Bigger knots | Higher sap content | More noticeable variation |
Rustic or CD | Displays a larger range of colour variation, more knots, and fillers, giving it a traditional vintage look | More knots and fillers | Higher sap content | More pronounced variation |
—
FAQ
What is wood grading in flooring?
Wood grading in flooring refers to how the wood used is classified by the manufacturers based on its appearance. This typically takes into account features like the number and size of knots, the amount of sap present in the wood, and its colour variations. The fewer the knots, the lower the sap content, and the more uniform the colour, the higher the grade of wood.
What are the different wood grades used in flooring?
There are typically four wood grades used in flooring, each with different characteristics and aesthetic qualities. These grades are Prime or AB, Select or ABC, Natural or ABCD, and Rustic or CD.
What are the characteristics of Prime Grade wood flooring?
Prime Grade, also known as AB-high grade, is the highest grade of wood flooring. It is cut from the center of the log, has a uniform appearance, contains very few knots, and has a low sap content. The colour variation is minimal due to the natural quality of the wood, giving it a uniform look.
What is the difference between Select Grade and Natural Grade wood flooring?
Select Grade, often referred to as ABC grade, contains some knots (though less than Natural grade), some sap, and some colour variation. Natural grade, also known as mill run or ABCD grade, sports larger knots than Select, contains more sap, and has more colour variation.
What is the Rustic Grade in wood flooring?
Rustic Grade is the final grade for wood flooring. It displays a larger range of colour variation, has more knots and fillers, and contains higher sap content, giving it a traditional vintage look.