Because wood is a completely natural product, it is entirely normal that colour, knots and sap vary from species to species, from grade to grade and even from batch to batch. This is one of the things that makes wood so interesting. The thing that governs the colour variations, knots and sap content more than anything else, is the grade of the wood used to make the flooring planks you choose. Manufacturers grade wood according to how it looks and this is undoubtedly one of the best ways of determining how much variation there is likely to be in colour; how many knots there is likely to be in the wood and how big they might be, as well as the amount of sap likely to be present in the wood.
There are four grades of wood to choose from, they are:
Prime or AB
Select or ABC
Natural or ABCD
and Rustic or CD
Although the names of the grades of wood may well suggest that certain grades might be better than others, it is important to point out that the grade of wood has absolutely nothing to do with the quality of the wood, it concerns itself purely with appearance. Equally, while many people may appreciate and prefer prime grade wood, there is nothing to suggest that a rustic grade won’t look great in the right setting.
Regarding colour variations in wood, prime grade wood flooring is highly consistent in its colour, with little variation, unless of course the wood itself is naturally variable, like some of the tiger woods for example. Select grade wood flooring on the other hand, while still being fairly consistent, does feature more of a colour variation than prime grade. You should expect natural grade and rustic grade wood flooring to show significant colour variations, but in many ways this can add to their charm, depending on the look you’re hoping to achieve.
While knots are an intrinsic part of the make up of wood, generally speaking, the higher the grade of wood, the smaller the size of the knots and the fewer knots there are. Prime grade wood for example, while it does contain knots, features knots that are small and unobtrusive. The other grades of wood typically sport knots that increase in size, as you move down the list of grades. If you choose select grade wood, for example, you should expect to see knots of up to 20mm; natural grade, up to 30mm and rustic up to 35mm. Although these sizes are only a guideline, it will give you a good idea of what to expect in terms of the variations of the size of knots between the grades.
Finally, when it comes to sap, again the amount of sap in the wood increases as you descend the list of grades. Sapwood is the part of a tree that is situated on the outside of the trunk and is the youngest part of the tree. As the wood matures it contains less sap and the wood with the lowest sap tends to be found at the heart of the trunk. Clearly you would expect the higher the grade of wood, the lower the amount of sap and you would be absolutely correct. Going down the list from prime to rustic, you will find an increased level of in sap in the wood used to produce your floor.
Which grade of wood you choose for your flooring project will depend not only upon your budget, but also on the overall look you’re trying to achieve. Like all things interior or design, this is highly personal, but if you feel you need help to make a decision, your wood flooring supplier should definitely be able to help you choose.
How To the Four Grades Compare
Wood Grade | Colour Variation | Knot Size | Sap Content |
---|---|---|---|
Prime (AB) | Highly consistent with little variation | Small and unobtrusive | Lowest amount of sap |
Select (ABC) | Fairly consistent with more colour variation than Prime grade | Up to 20mm | More sap than Prime grade |
Natural (ABCD) | Significant colour variation | Up to 30mm | More sap than Select grade |
Rustic (CD) | Significant colour variation | Up to 35mm | Highest amount of sap |
Notes:
- The colour variation increases from Prime to Rustic grade.
- Knot size increases from Prime to Rustic grade.
- Sap content increases from Prime to Rustic grade.
- The grading is primarily about appearance and doesn’t affect the quality of the wood.
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FAQ
What is wood grading and how does it affect the appearance of wood flooring?
Manufacturers grade wood according to how it looks, which determines the colour variations, knots and sap content in the wood. The grade of the wood is purely about appearance and doesn’t affect the quality of the wood.
What are the four grades of wood?
The four grades of wood are Prime or AB, Select or ABC, Natural or ABCD, and Rustic or CD.
How does wood grading affect colour variations in wood?
Prime grade wood flooring is highly consistent in its colour with little variation. Select grade wood flooring, while still fairly consistent, features more colour variation than prime grade. Natural grade and rustic grade wood flooring show significant colour variations.
What is the effect of wood grading on the size and number of knots in the wood?
The higher the grade of wood, the smaller and fewer the knots. For example, Prime grade wood features small and unobtrusive knots. The other grades of wood typically sport knots that increase in size as you move down the list of grades.
Does the amount of sap in wood vary with its grade?
Yes, the amount of sap in the wood increases as you descend the list of grades. Sapwood is the part of a tree that is situated on the outside of the trunk and is the youngest part of the tree. As the wood matures it contains less sap, and the wood with the lowest sap tends to be found at the heart of the trunk.