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Parquet grading and selection

When choosing a wooden floor, one of the most common questions concerns the quality of the material and the so-called first, second, or other grades.
It’s a topic that often creates confusion and therefore deserves a clear and careful explanation.

As with marble or ceramic tiles, the parquet industry also tries to classify materials based on certain characteristics, defining selections and categories.
However, unlike many other materials, in the case of wood it’s not correct to speak of defects, but rather of natural characteristics.

Wood is a living, authentic material, and for this very reason it is never identical to itself.

“Defects” in wooden floors

Let’s emphasize once again that—unlike many other materials—when it comes to wood, it’s not correct to speak of “defects.” Wood is a natural material, and variations in tone, grain, and the pattern of the veining are absolutely normal characteristics of the tree itself.

Each parquet plank comes from a different tree or from a different part of the same trunk.

Variations in:

• color tone

• grain pattern

• presence of knots

• more or less pronounced fibers

are completely normal and are part of the very nature of the material.

Expecting a perfectly uniform parquet floor essentially means stripping wood of its natural character, or choosing products that are heavily selected, treated, or artificially standardized.

What “grading” means in parquet flooring

When we talk about first grade, second grade, or other selections, we are not defining a parquet floor as “good” or “defective,” but rather indicating the level of aesthetic variation that is allowed.

Grading helps define:

• how much uniformity you can expect

• how much natural character will be visible in the finished floor

The more restrictive the selection, the more uniform the parquet will appear.
The more open the selection, the more the floor will tell the story of the tree it comes from.

Harmonization of grading criteria at European level

At a European level, a decision has been made to classify parquet boards—based on specific characteristics—into three different grades: the “circle” grade, the “triangle” grade, and the “square” grade.
The choice to avoid terms such as “first grade” or “second grade” and instead use geometric shapes is not accidental.

Commercial classifications

Standardizing this system helped put an end to the confusion that existed when each manufacturer defined its own classifications, using names such as “rustic,” “nature,” “fine straight grain,” or “flamed.”

It must be said, however, that these commercial classifications were often easier to understand. Wood was described in a much more artisanal and visual way. The so-called grades were not abstract commercial codes, but terms that conveyed the real appearance of the wood—its cut and its character. Words like straight grain, flamed, knotted, or rustic were part of the everyday language of carpenters, installers, and retailers, and they made it immediately clear what kind of floor one was choosing.

In everyday commercial practice, some of these terms are still used today. For this reason, when purchasing a parquet floor, it’s still possible that a salesperson will describe it using expressions such as straight grain, small knots, or rustic.

Parameters that define the grading of a wooden floor

Please note: the European classification focuses on appearance, meaning the presence of more or less regular grain patterns and a consistent coloration. It does not take into account other qualitative aspects of the board, such as the quality of the backing layer, the type of surface treatment, or the adhesive used.
In other words, a parquet floor that looks aesthetically pleasing may still have a poor-quality support or an inadequate protective finish.

The characteristics described below—associated with the different grades—refer specifically to oak parquet, which represents the vast majority of parquet flooring sold and, in any case, provides a reliable reference point for many other wood species as well.

The “circle” grade in oak parquet

In the circle grade:

• sapwood is not permitted

• knots are not permitted, not even sound knots, unless they are smaller than 8 mm

• filled rotten knots are not permitted unless they are smaller than 1 mm

• cracks are not permitted

• bark inclusions or lightning strikes are not permitted

• deviation of the grain is allowed

• slight color variation is allowed

• ray flecks or silver grain (caused by medullary rays) are allowed

This grade therefore corresponds to what we might call a first-grade parquet, characterized by:

• fairly uniform color tones

• regular grain patterns

• very small knots or almost no knots at all

It is the most suitable choice for those who want:

• elegant interiors

• a contemporary or minimalist style

• a neat, understated, and discreet wooden floor

It’s always important to remember that even a first-grade parquet is never perfectly identical: wood remains a natural material and, no matter how much effort is made to “standardize” it, it will never achieve the uniformity of a printed or industrial material.

The “triangle” grade in oak parquet

In the triangle grade:

• sound sapwood is permitted

• knots are not permitted, not even sound ones, unless they are smaller than 10 mm

• filled rotten knots are not permitted unless they are smaller than 5 mm

• cracks are permitted up to 15 mm in length

• bark inclusions or lightning strikes are not permitted

• deviation of the grain is allowed

• color variation is allowed

• ray flecks or silver grain (medullary rays) are allowed

These characteristics—which are often incorrectly associated with a “second-grade” classification—do not compromise either the quality or the durability of the parquet.

On the contrary, they make the floor:

• warmer

• more authentic

• more tactile and material-rich

This grade is perfect for:

• warmer or contemporary interiors

• lived-in homes

• those who love real wood, without filters

As already mentioned, the grade of parquet does not define the quality of the backing layer, the adhesives, or the protective finish. For this reason, it’s entirely possible to find a “second-grade” parquet (more accurately, a triangle grade) that costs more than a “first-grade” one, simply because it is constructed with higher-quality materials and finishes.

Knot ≠ defect

Since this “third grade” also allows knots, it’s worth taking a closer look at a feature that is often misunderstood. Knots, which are frequently perceived as defects, are actually the point where a branch grows from the trunk. And trees have branches—otherwise, that would be quite unusual.

In short, knots are a structural characteristic of wood and, when they are sound and properly worked, they do not compromise the strength or durability of the floor. Many modern parquet floors deliberately highlight these elements, because they tell the truth of the material and express its authenticity.

A knot-free wood is like a tree without branches…

No single grade is better than the others

There is no such thing as an objectively “better” parquet grade.
There is only the grade that is right for your specific project.

A very uniform parquet can be perfect in a modern penthouse, just as a parquet rich in knots and natural variations can be stunning in a country house or in a contemporary interior where surfaces are used to create warmth.

The biggest mistake is choosing parquet without coordinating it with the rest of the interior finishes, or assuming that a “first-grade parquet” automatically guarantees superior technical construction of the product.

Choose the right consultant for your parquet

Understanding the differences between the various parquet grades means:

• avoiding disappointment after installation

• making a well-informed choice

• achieving a result that is consistent with the overall style of the home

A good parquet project begins before installation, through careful listening to your needs and a clear explanation of what is normal, natural, and desirable in wood. To make the right choice, it’s advisable to rely on an architect—whether among the best architects in Vicenza or Verona—or on a trusted flooring showroom with proven experience and a solid reputation.