Wood Flooring Grades Explained

April 14, 2014

Timber is a natural material with a great variation in appearance, knots, colour and grain patterns within one species. In order to separate hardwood flooring in to different groups well defined wood flooring grading system was introduced.

Wooden floors are graded to enhance the natural beauty of each individual timber by taking in to consideration three following major factors:

– size and number of knots,

– colour variation,

– amount of sap present in the wood.

Generally speaking the higher the number of knots, higher the sap content and the more variety in colour – the lower the grade of timber. Usually it is sufficient to grade a wood flooring into 3 grades – Prime, Natural and Rustic.

Prime Grade

Also known as Select or AB grade is the highest of the three grades of flooring and would usually have the following characteristics:

Slight colour variation between the boards  and more uniform look except for timbers where variation in colour adds to its beauty and is the main feature of the wood. The grain is straighter than in other grades and sometimes the boards have very few, infrequent small knots unless these are specific to the beauty of the timber. Prime grade wooden floors are the most expensive due to the limited supply in the raw material.


Natural Grade

Also known Character or ABC grade is the middle timber grade and shows more character than prime grade but less than the rustic grade. Timber can display more infrequent knots, more variations in colour and texture, some mineral streaking and grain pattern. Again, interpretation of the grain will vary from species to species and for example you can expect much wider natural colour variation in natural graded Elm (from white to dark brown) while in the natural oak flooring there is a less obvious variation – from cream to dark brown.

In natural grade wood flooring you can expect knots of up to 30mm in diameter, flashes of colour, burrs and other character marks. Boards can display few small black knots and delicate machinery defects that can be sanded down very easily. During the kiln drying process knots crack slightly. After initial sanding they are filled with a mixture of sawdust and resin before sealing.


Rustic Grade

Also known also as Millrun or ABCD contains vibrant colourful patterns, unlimited knots of varying sizes and unlimited colour variation. Floor can display heavy grain markings, figuring and mineral staining.

In rustic grade flooring black  knots and surface cracks as well as occasional machining defects can be seen.

This flooring offers great value for money, as the majority of the raw material will contain this type of grade, without compromising on the quality, wear and stability of the floor.


If you have a further questions regarding wood flooring grades or you are looking for an advice about the best wood flooring for your home feel free to contact the ESB sales team. Contact us now to request your no hassle no obligation free samples or come down to our North London showroom for a closer look.

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