What's your main concern when you buy wooden flooring from the market? Price, Quality, or Design? Actually there are no products is cheap but with high quality, everybody knows that the price is related to reasonable quality, How many information do you know about wooden flooring? How to know different grade of wooden flooring ? below some knowledge may help you.
In wooden flooring industry, people use "ABCD" to distinguish different grade of the wooden flooring, Actually, this grading system is not standard for floor quality, A good quality flooring should be in good condition of dimension stability, in a certain level of moisture content, A hardness of surface treatment...etc. Here called "ABCD" is the grade of wood grain appearance. For natural wood, there is different wood grain between core material and the periphery of the wood, In the middle of the wood, the grain is more clear and natural than wood periphery, and there are more knots and cracks.
Actually, there are no standard grade rules for the wooden flooring , but each floor companies has their own grade rules , Here are the grade rules from SensseWood for your reference:
crack with putty
Should be in the middle part of the timber in good grain appearance. The wood grain is clear enough, no sapwood, no crack. The live knot less than 3mm is accepted, but dead knots and black line are not acceptable.
Natural black line, live knots and dead knots less than 5mm is accepted. No stain, no color change, no sapwood, no pine hole and rot.
Accept black line, color stained, and live knots. sapwood and dead knots less than 30%.
Accept color change, sapwood, and live knots. Cracks and dead knots with putty is also accepted.
Hope above description of the grade rules may be helpful to you to get more knowledge of wooden flooing.