Natural Shrinkage and Expansion

Tongue and groove timber floors are a completely natural material, which is seasoned and machined to the right profile to become your floors.

Natural timber is hygroscopic; it continually takes up and gives off moisture to keep in balance with its surroundings, resulting in natural shrinkage and expansion. Depending on the timber species chosen, visible shrinkage and/or expansion may take a day, a week or even months, resulting in the gaps between floorboards opening and closing depending upon the weather, the season and local conditions.

To reduce the degree of shrinkage and expansion, today’s timber flooring is generally seasoned or kiln dried to an average moisture content of between 10% and 15%. This is considered to be a good starting point for the majority of installations, but as you will read later, many other local factors influence the atmospheric moisture content of your home and therefore affect your floor.



 Timber Colour

This is purely a personal and aesthetic choice. The general colour will be determined by the timber species. However, even within one species there will be natural variations. Some species exhibit only small variations while others vary greatly. Remember; timber is a natural product and no matter how many samples you have seen, your floor WILL BE DIFFERENT from the samples and completely unique.

The true colour of a floor will only become evident after it has been sanded and coated with a chosen finish. A darker floor will make the room appear darker, and may therefore require more available daylight and/or artificial light sources. Darker coloured floors tend to show dirt and marks more than lighter floors.



 Timber Features

Depending upon the species chosen, various combinations may be available. You may prefer a mix which shows a variety of natural features including colour, knots, gum vein (darker lines) and insect markings to provide unique visual impact, or you may prefer a mix which offers continuity and consistency with few outstanding features. It's up to you.



 Board Width

Tongue and grooved flooring is generally supplied in nominal profile widths of 85mm, 108mm or 133mm. (Actual cover width of boards will vary depending on the profile type). The width of the boards and the direction they are laid will affect the look of a room. Generally boards laid along a room will make the room look longer while boards laid across a room will make it look wider. Other factors such as subfloor materials may control the direction the boards must be laid.

The wider the floor board the greater the natural shrinkage/expansion across the face. Therefore during dry periods wider boards may exhibit slightly wider gaps between boards and cupping may also be more apparent. When the floor has been properly laid by professionals, both of these conditions generally disappear after a reasonable period of normal humidity/weather conditions.



 Grades of floor boards

Most floorboards offer a selection of three different grades; select (SEL), medium feature (MF) and high feature (HF).

  • Select grade has a relatively even grain and figure that provides a rich and generally uniform texture and surface.
  • Medium feature (Standard) provides a surface with distinct natural appeal. Features that may affect structural soundness are excluded.
  • High feature provides a surface that is rich with a lively and vibrant character.

All grades of timber are allowed the same amount of distortion; this is governed by product type rather than timber grade.



 Timber Hardness

You may also need to consider the hardness of the timber if you expect exceptionally heavy traffic or you are a big fan of high heels! Talk to us about your needs.

The Janka hardness test measures the force required to embed a .444 inch steel ball to half its diameter in wood. It is one of the best measures of the ability of a wood species to withstand denting and wear. By the same token, it is also a good indicator of how hard or easy a species is to saw or nail. Northern Red Oak, for example, has a janka hardness rating of 1290. Brazilian cherry, with a rating of 2350, is nearly twice as hard.



Janka Rating


     Janka Rating

Spotted Gum




Brazilian Cherry


White Oak




Tasmanian Oak










Australian Beech


Red Oak






Sydney Blue


Heritage Oak




Alpine Ash






Rose River Gum













Popular timber species  

Tasmanian Oak

(Eucalyptus delegatensis / Eucalyptus regnans / Eucalyptus obliqua)

The name Tasmanian Oak is used to describe three species of Eucalypt commonly found in Tasmania. Together they produce a blend of beautiful colouring from pale cream to pink and reddish-brown.

Spotted Gum

(Eucalyptus maculata)

The word "spotted" refers to the soft mottled colour caused by weathering of the outer tree as it sheds elliptical strips of bark. This colour varies from pale greybrowns and soft creams to a rich chocolate brown. A very tough timber, its frequent wavy grain can produce an attractive and highly valued fiddleback effect.


Messmate is a well-known hardwood species that is used in a variety of timber applications but is in high demand as timber flooring due to its beauty. It varies in colour from pale browns through to light yellows with subtle hints of peach. It is a species that is rich in detail with an even texture and visible growth rings.


(Eucalyptus pilularis)

Blackbutt is a commonly grown hardwood that has an attractive colouring from cream to pale brown, sometimes with a slight tinge of pink. Its grain is usually straight and its texture is medium and even.



(Eucalyptus marinata)

One of the few commercial species from Western Australia, Jarrah is renowned world-wide for its density, resistance to insect attack and beautiful rich red colour which deepens over time into a soft burgundy. Jarrah’s beautiful colouring and exceptional hardness are a perfect combination for commercial and residential flooring.


Sydney Blue Gum

(Eucalyptus saligna)

A well-known timber found on the east coast of Australia, Sydney Blue Gum has a straight grain that is sometimes interlocked. Its distinctive colour range goes from dark, rich pink through to deep red-brown.



(Eucalyptus microcorys)

Tallowwood is a prestigious timber that is sought after by architects. It is an exceptionally durable hardwood species with unique colour and grain structure. The colour of Tallowwood varies from yellowish brown with a tinge of olive green to distinctively paler shades. The grain is even and often interlocked.



A blend of a number of eucalyptus varieties native to various areas of New South Wales. The texture of stringybark is moderately fine and even with a straight grain. It is generally a light coloured timber ranging from pale yellows through to soft golden hues. The neutral tones of stringybark complement the most modern or traditional of designs and are great for both commercial and domestic applications.


(Eucalyptus diversicolor)

Karri is a lively red colour with overtones from pale pink to rich reddish brown. Karri’s high density and hardwearing qualities make it highly sought after by architects.



(Lophostemon confertus)

Brushbox has long been sought after for its unique properties and aesthetic qualities. It has a fine and even texture with a beautiful, rich colour. It can vary in colour from a pinkish grey to a rich, reddish brown, with the sapwood distinctively paler.