Wood, as a natural material, is highly valued in construction projects. Understanding its different properties is essential to ensuring its durability and aesthetic appeal.  In this article, we explore the different characteristics of wood, to give you a better understanding of this natural, living material.

Distinctive features of wood: definition

Unique characteristics of wood linked to its genetic code

Each species of wood has a unique genetic code that determines its physical and mechanical characteristics. These genetic variations can influence the colour, grain, density and other properties of the wood.

Unique features of wood linked to its composition

Wood is made up of several substances such as cellulose, hemicellulose and lignin, as well as various natural extracts such as tannins, resins and oils. The proportion and distribution of these components can vary depending on the species of wood and its growing conditions (see below), thus influencing the mechanical and aesthetic properties of the wood.

Unique characteristics of wood linked to its growth conditions

The environmental conditions in which a tree grows play a crucial role in shaping its characteristics. For example, trees growing in colder climates tend to have narrower growth rings, which can make the wood denser and more resistant.

Singularities in wood influenced by living organisms

Interactions with living organisms, such as insects, fungi and bacteria, can create singularities in wood. For example, insect attack or fungal infection can lead to areas of discolouration, adding character and distinction to the wood.

Distinctive features of the wood linked to the drying and treatment process

After harvesting, the wood undergoes drying and treatment processes that can also affect its properties. Air or kiln drying can cause variations in the texture and colour of the wood.

Reactions to Environmental Conditions

Wood continues to react to its environment even after it has been cut and processed. It can absorb or lose moisture depending on ambient conditions, resulting in dimensional variations and changes in its mechanical properties. This reactivity adds a dynamic, living dimension to wood, distinguishing it from inert materials.

What are the different characteristics of wood ?

Wood is a natural material with imperfections. However, these imperfections in no way affect the durability of the wood.

A strip of wood cladding is therefore alive and will go through many phases throughout its life cycle. Climate change, pollution, the nature of the soil, etc. are all factors that can have an influence on the characteristics developed.

Here are the main features or natural phenomena that you can observe on your wood cladding boards:

resin pocket wood cladding

Example of resin pocket on Douglas fir cladding

Resin build-up

Resin build-up on wood cladding, particularly on softwood species such as pine, Douglas fir or Larch, is a natural phenomenon caused by the presence of resin or sap inside the wood.

Wood, as a living material, continues to react to its environment even after it has been transformed into a cladding board. Fluctuations in humidity and climatic conditions, such as periods of severe drought or prolonged exposure to the sun, can affect the viscosity of the resin, causing it to rise.

As a preventive measure, choosing less resinous woods or species such as pine that have been heat-stabilised can reduce the frequency and extent of resin build-up.

Example of greying on a façade clad in saturated wood.

The greying of wood

The phenomenon of wood greying on a cladding board is a natural process resulting from prolonged exposure to external elements, mainly sunlight, humidity and climatic variations. There is no loss of strength or durability.

Untreated wood cladding, or wood cladding not protected by an appropriate finish such as a saturator, will grey more quickly.

Saturated finishes for wood cladding act as a protective barrier against UV rays and humidity. To prevent greying, simply maintain your cladding every 3 to 5 years by applying a saturator to revive the original colour of your wood cladding. If your wood cladding has already gone grey, there are woodstain removers available to restore the colour of the wood.

Surface foams

Surface mosses on wood cladding are generally the result of environmental conditions that favour their growth. Shaded, damp areas on wood cladding create a favourable environment for moss growth. Moisture accumulated on the surface of the wood, combined with reduced exposure to sunlight, encourages the development of spores.

By adopting appropriate management practices (brushing and cleaning the wood), you can minimise the impact of moss and maintain the aesthetically pleasing appearance of your building's façade.

Example of surface cracks

Example of surface cracks

Splits, cracks and fissures in wood

Wood is a hygroscopic material, which means that it absorbs and releases moisture depending on environmental conditions. Repeated episodes of temperature and humidity fluctuations caused by global warming can cause movement in wood. Prolonged exposure to sunlight, followed by periods of cold and rain, increases internal stresses and can cause narrow cracks and splits running the length of the board.

differences in cladding colours

Example of colour differences on larch cladding

Colour differences

Wood species offer an incredible diversity of natural shades, from light, neutral tones to deep, rich shades. These variations are influenced by a number of factors, including the species of wood and the conditions in which it grows. By understanding the natural shades of each species, it is possible to choose the wood best suited to a specific project, according to your aesthetic preferences.

knots in wood cladding

Example of knots on wood cladding made from Scots pine

The presence of knots

Knots are a natural characteristic of wood, resulting from the growth of branches from the tree trunk. The frequency of knots varies according to wood species and quality, but they do not represent a mechanical defect.

What type of wood cladding should I choose, given the specific characteristics of each type of wood ?

The choice of exterior wood cladding depends above all on the aesthetic appeal you want to bring to your façade. The characteristics of the different types of wood play an important role in this decision. Here's a guide to help you choose the right wood cladding for your needs, taking into account the specific characteristics of each species.

The unique features of Cedar wood cladding

  • Distinctive features: very slow-growing species, fine grain, 95% knot-free, pinkish-red colour, naturally resistant to insects and mould.
  • Advantages: Excellent durability, attractive appearance, low maintenance.

See our guide to western red  wood cladding

The unique features of Larch wood cladding

  • Distinctive features: slow-growing species, fine, even grain, medium-sized knots, orange-yellow to reddish-brown colour, knots present, good natural resistance.
  • Benefits: Durable and resistant to demanding climates

Consult our Larch wood cladding guide

The unique features of Scots pine wood cladding

  • Characteristics: slow-growing species, fine veining, frequent knots, light colour.
  • Advantages: no resin build-up if the wood is heat-stabilised

See our guide to Scots pine wood cladding 

The unique features of Douglas fir wood cladding

  • Distinctive features: fast-growing species, marked distinctive features with medium to large knots, reddish colour.
  • Advantages: good value for money

Consult our guide to douglas fir wood cladding

The unique features of Spruce wood cladding

  • Distinctive features: slow-growing species, small to medium-sized knots, light-coloured wood.
  • Advantages: good value for money

See our guide to spruce cladding

 

In conclusion, wood is a living, dynamic material whose uniqueness is shaped by a multitude of factors. From its unique genetic code to its chemical composition, via its growth conditions and interactions with the environment and living organisms, each species of wood tells a distinct story. Variations such as resin bleeding, greying, surface moss, splits and cracks, differences in colour and the presence of knots, although often perceived as imperfections, actually contribute to the beauty and uniqueness of wood. Understanding and accepting these natural phenomena not only enhances our appreciation of wood as a building material, but also enables us to use it in a more sustainable and aesthetically pleasing way. By adopting appropriate management practices and preventive treatments, it is possible to preserve and enhance the exceptional properties of this noble and environmentally-friendly material.

To find out more, contact one of our wood experts.