What are the different grades of wood flooring?

wood flooring Sevenoaks

No two trees are the same, even two trees of the same species. Indeed, it’s this kind of variation that makes wood such a beautiful and flexible material to use in the home. The mood and style evoked by a wooden floor depends on the particular properties and qualities of the wood, and it’s important to know how to differentiate these.

Here in the UK, each wooden floor is graded in line with a system that every manufacturer in the industry uses. This classification system has the benefit of making your interior design choices a lot easier at the planning and purchasing stage. In this post, we outline this system and explain the meaning of each grade.


What are the criteria?

The sorting and grading of wood is not an exact science. The grade assigned to a particular batch of wood flooring is decided by manufacturers at the factory, and workers base each grading on the appearance of the wood at a glance. There are specific criteria by which wood is classified, although these criteria can differ from one manufacturer to another (as well as from one species of tree to another).

As such, the grade of your wood flooring should only act as an indication of its properties – albeit one based on the opinion and experience of an expert. Generally speaking, each grade is decided on the basis of the following criteria:


  • The size and number of knots in the grain.
  • The width and shape of the grain pattern.
  • The colour variation across the wood.
  • The amount of sap visible in the wood.


UK classification system

Since there is no international standard when it comes to sorting and classifying wood, the grading systems we use can get quite confusing. This is especially true with imported lumber which cannot be adequately classified using our own grades. This is why you often see ad hoc categories which depart from the basic UK system (‘select’, ‘classic’ and ‘millrun’ grade woods) on the flooring market.

To remove these blurred lines, it’s best to judge wood flooring based only on the three most commonly used grades: prime, natural and rustic grades.


Prime grade

Lacking in natural imperfections and brimming with smooth textures, prime grade flooring is defined by its look of uniform elegance. This type of flooring boasts fine and smooth grain patterns with little to no knots. Any knots that do exist in the wood are either covered up with filler or too subtle to be noticed. The filler used for knots is carefully matched to the colour of the wood, giving it a uniform colouring with little variation throughout.

Prime grade flooring has very few of the character marks which naturally occur in wood, the likes of which are usually embraced by other grades of wood flooring. It’s about as free of imperfections as a natural material like wood can possibly be, making it the most logical choice for a sleek interior with clean lines and monochrome palettes. Prime grade wood is typically in shorter supply as it is cut from the centre of the log, making it one of the more expensive options on the market – they don’t call it prime for nothing!


Natural grade

Though still largely consistent in appearance, natural grade flooring has some minor imperfections sparsely distributed across the wood. You should expect a few knots, some infrequent flashes of colour, slightly busy grain patterns, and the occasional instance of sap.

The size of knots (as well as the amount of filler) in natural grade woods will depend on the exact criteria followed by the manufacturer – there will usually be variations in the size and colour of knots. Consider this type of wood a middle ground choice for your flooring, giving you that traditional character while holding back slightly on those more striking imperfections.


Rustic grade

By far the most natural and least uniform grade of wood, rustic grade flooring exhibits a wide range of different colours and a whole host of vibrant patterns. This type of wooden flooring embraces imperfections to the full, replete with mineral streaks, stark grains, sap lines, and an abundance of knots (both filled and unfilled). Some manufacturers even leave unnatural flaws in the wood, such as cracks in the surface caused by machinery.

Rustic grade wood still enjoys the strength and durability of other wood grades, only at a fraction of their price. Although not for everyone, the natural charm and warmth of rustic grade flooring is compatible with a number of modern interiors. Indeed, rustic floors are commonly found in shabby-chic cafés, pastoral farm houses, and lakeside log cabins.


If you’re looking for more advice and information from seasoned experts in the flooring industry, feel free to get in touch with a member of the Hudson Flooring team and we’d be delighted to help you out.