Structural timber is timber selected, graded, and prepared for applications where it is expected to carry loads or contribute to the structural stability of a building or structure. Unlike timber used mainly for decorative purposes, structural timber must meet specific requirements for strength, stiffness, dimensions, moisture content, durability, and defects.

It can be used for beams, columns, roof structures, floor joists, rafters, wall framing, trusses, bridges, timber-frame buildings, and other load-bearing applications.

However, an important point is often overlooked: a timber species is not automatically structural timber simply because it is strong or dense. Structural suitability depends on the grade, dimensions, moisture condition, defects, applicable standards, and the requirements of the particular project.

For timber buyers, builders, architects, and importers, understanding these differences is essential when selecting structural timber.

What Is Structural Timber?

It is solid or engineered timber manufactured, graded, or classified for use in load-bearing construction.

The term generally refers to timber products whose mechanical properties are sufficiently known and controlled to allow them to be considered in structural design.

Structural timber may include:

• Sawn structural timber
• Structural softwood
• Structural hardwood
• Glulam
• Laminated veneer lumber (LVL)
• Cross-laminated timber (CLT)
• Other engineered timber products

Depending on the market and product, structural timber may be visually graded, machine graded, strength classified, or manufactured according to a recognized product standard.

The objective of grading is to identify timber with predictable structural characteristics. Features such as knots, grain deviation, splits, checks, density, slope of grain, and other defects can influence how a piece of timber performs under load.

Why Is Structural Timber Important?

Buildings and other structures are exposed to different types of loads. Timber members may need to resist bending, compression, tension, shear, or combinations of these forces.

For example, a floor joist primarily experiences bending and shear, while a column may experience significant compression. A roof truss can contain members subjected to both tension and compression.

Selecting timber based solely on appearance or species name is therefore not sufficient.

The timber must be appropriate for the intended structural application and comply with the standards and engineering requirements applicable to the project.

Structural Timber Grades Explained

Timber grading is one of the most important concepts to understand when purchasing structural timber.

A grade provides information about the expected structural performance of a piece of timber. Different countries and standards use different grading systems, so grades should not automatically be treated as interchangeable between markets.

What Does Timber Grading Mean?

Timber grading involves evaluating characteristics that can influence structural performance.

Depending on the grading system, these characteristics can include:

• Knots
• Slope of grain
• Checks and splits
• Density
• Growth characteristics
• Resin pockets
• Wane
• Fissures
• Decay
• Insect damage
• Moisture content
• Modulus of elasticity
• Strength-related characteristics

A grading system establishes limits or requirements for these characteristics and places timber into a recognized structural category.

The result is a more predictable material for structural design.

Visual Grading

Visual grading is performed by inspecting timber and assessing visible characteristics that can affect its strength.

A trained grader may examine:

• Knot size and location
• Grain direction
• Splits
• Checks
• Wane
• Distortion
• Decay
• Other visible defects

Visual grading does not mean that the timber is judged simply by whether it looks attractive. Structural visual grading is based on defined criteria related to performance.

A piece with a clear, straight grain may have favorable characteristics, while large knots or severe grain deviation can reduce its structural capacity.

Machine Grading

Machine grading uses equipment to measure properties associated with structural performance.

Machine stress grading can assess characteristics such as stiffness and may then assign timber to a defined strength class according to the applicable standard.

This can provide a more objective approach to structural classification, although the exact process depends on the grading system and product.

What Is C24 Structural Timber?

C24 is a commonly recognized strength class used for structural softwood in certain European grading systems.

The letter C identifies a strength class for softwood, while the number represents the class within the relevant standard.

C24 timber is therefore not a particular tree species.

This distinction is important.

A supplier should not simply describe a random piece of timber as “C24” because it appears strong. The timber must meet the requirements of the applicable grading and classification standard.

Other strength classes exist, and the appropriate class depends on the product, species, grading method, and applicable standard.

C24 Does Not Mean Every Timber Is C24

Different species and timber products have different characteristics. Furthermore, structural classification is affected by grading procedures, manufacturing, dimensions, moisture conditions, and standards.

Consequently, buyers should request appropriate grading or classification documentation when purchasing structural timber for a project.

Structural Timber Strength

The strength of timber is not represented by a single number.

Timber can experience several different types of mechanical loading, and its performance depends on the direction and type of force applied.

Important structural properties include:

Property	What It Describes
Bending strength	Resistance to bending forces
Compression strength	Ability to resist compressive loads
Tensile strength	Ability to resist pulling forces
Shear strength	Resistance to forces acting parallel to a surface
Modulus of elasticity	A measure related to stiffness
Density	Mass per unit volume and an important physical characteristic
Dimensional stability	Resistance to movement caused by moisture changes

These properties can vary considerably between species and even between individual pieces of the same species.

Bending Strength

Bending strength is particularly important for members such as:

• Beams
• Floor joists
• Rafters
• Some roof members
• Certain bridge components

When a beam carries a load, it bends. The timber must have sufficient structural capacity to withstand the expected loading without excessive failure or deformation.

Compression Strength

Compression occurs when forces push timber together.

Columns and posts are common examples.

Compression performance can be affected by:

• Timber species
• Density
• Defects
• Grain direction
• Member dimensions
• Length
• Moisture
• Connection details
• Structural configuration

Long slender timber members may also be affected by buckling, meaning that simply knowing the compressive strength of the timber itself is not enough to design a column.

Tensile Strength

Tension occurs when a member is pulled apart.

Timber can have significant strength parallel to the grain, but defects and grain deviation can substantially influence performance.

Tension may be important in:

• Trusses
• Structural frames
• Certain connections
• Engineered timber systems

Shear Strength

Shear forces act parallel to a material’s surface or cause adjacent sections to slide relative to one another.

Shear can be important around supports and connections, particularly in beams.

Factors That Affect Structural Timber Strength

Several factors influence the structural performance of timber.

1. Species

Different species have different densities, grain structures, natural durability, stiffness, and strength characteristics.

However, species alone does not establish a structural grade.

2. Knots

Knots are natural features formed where branches develop from the tree.

Large or strategically located knots can affect strength, particularly when they interrupt the straight grain of the timber.

3. Grain Direction

Straight grain is generally desirable for many structural applications.

Significant slope of grain can influence mechanical performance because timber is naturally anisotropic, meaning its properties differ according to direction.

4. Moisture Content

Moisture has a significant influence on timber properties and dimensional movement.

Timber may shrink as it dries and swell as it gains moisture. Excessive or changing moisture conditions can therefore affect both dimensions and performance.

5. Density

Density is an important characteristic associated with many timber properties. Dense species often have different mechanical characteristics from lightweight species, although density alone should not be used to assign a structural grade.

6. Defects and Damage

Decay, insect attack, severe checks, splits, excessive wane, and manufacturing defects can affect structural suitability.

7. Dimensions

The dimensions of a structural member influence how it performs under load.

A timber beam measuring 100 × 200 mm does not behave the same way as a smaller member simply because they are made from the same species.

Moisture Content in Structural Timber

Moisture content is a critical consideration when purchasing and using structural timber.

Freshly harvested timber contains considerably more moisture than properly dried timber. As timber dries, its dimensions can change.

This movement can affect:

• Width
• Thickness
• Length
• Joints
• Connections
• Surface condition
• Dimensional stability

Kiln-Dried Structural Timber

Kiln drying uses controlled temperature, humidity, and airflow to reduce timber moisture content.

The target moisture content should correspond to the intended application and environmental conditions.

For indoor construction, timber may require a different moisture condition than timber intended for an exterior environment.

There is therefore no single moisture-content number that is universally correct for every application.

Buyers should specify the intended use and applicable requirements when ordering timber.

Types of Structural Timber

It can be divided into several broad categories.

Type	Description	Typical Applications
Sawn structural timber	Solid timber cut from logs into specified dimensions	Beams, joists, rafters, framing
Structural softwood	Softwood graded for structural applications	Framing, roofs, floors, walls
Structural hardwood	Hardwood selected and classified for structural use	Beams, posts, bridges, heavy construction
Glulam	Layers of timber bonded together	Large beams, columns, roof structures
LVL	Laminated veneer-based structural product	Beams, joists, headers, structural framing
CLT	Cross-laminated timber panels	Walls, floors, roofs, mass timber buildings

The correct product depends on the design, span, loading, environment, availability, and applicable building standards.

Structural Softwood

Softwoods are widely used for structural construction in many markets.

Common examples include various grades of:

• Pine
• Spruce
• Fir
• Douglas fir
• Other commercially available softwood species

Structural softwood is frequently used for:

• Wall framing
• Roof framing
• Floor joists
• Rafters
• Trusses
• General building frames

One of the advantages of softwood is its relatively low weight compared with many dense hardwoods, combined with good strength-to-weight characteristics in appropriate grades.

However, the actual performance depends on the specific species, grade, dimensions, moisture condition, and standard.

Structural Hardwood

Hardwoods can also be used for structural applications.

Certain hardwood species provide high density, strength, stiffness, and natural durability, making them suitable for demanding applications when properly graded and specified.

Potential applications include:

• Heavy beams
• Posts and columns
• Bridges
• Outdoor structures
• Heavy-duty flooring
• Marine-related construction in appropriate applications
• Architectural structural elements

Examples of hardwoods that may be encountered in structural timber markets include species such as:

• Teak
• Iroko
• Doussie
• Azobé
• Padauk
• Oak
• Cumaru

This does not mean that every piece of these species is automatically approved for structural use.

The timber still needs to meet the applicable requirements for its intended application.

Engineered Structural Timber

Engineered timber products have expanded the possibilities for timber construction.

Instead of relying exclusively on a single solid-sawn member, engineered products are manufactured by bonding or arranging timber components in controlled configurations.

Glulam

Glulam, or glued laminated timber, consists of multiple timber laminations bonded together.

It is commonly used for:

• Large beams
• Columns
• Roof structures
• Long-span architectural structures
• Curved structural elements

One advantage of glulam is that large structural members can be manufactured from smaller timber components.

LVL

Laminated veneer lumber is manufactured from thin wood veneers assembled and bonded to form a structural product.

LVL is commonly used for:

• Beams
• Headers
• Joists
• Structural framing
• Long structural members

Its manufacturing process allows the product to have relatively consistent properties compared with many naturally variable solid timber members.

CLT

Cross-laminated timber consists of layers of timber boards arranged in alternating directions and bonded together.

CLT panels can be used for:

• Floors
• Walls
• Roofs
• Modular construction
• Mass timber buildings

Its panel construction makes it different from conventional solid-sawn structural timber.

Common Uses of Structural Timber

It is used across residential, commercial, industrial, agricultural, and infrastructure projects.

1. Roof Structures

Structural timber is widely used for:

• Rafters
• Roof beams
• Trusses
• Purlins
• Other roof framing members

The timber must be appropriately graded and sized for the loads and span involved.

2. Floor Joists

Floor joists support flooring systems and transfer loads to beams, walls, or other supporting members.

Important considerations include:

• Span
• Spacing
• Loading
• Timber grade
• Member dimensions
• Deflection requirements

3. Beams

Timber beams can transfer loads across openings or between supporting points.

They are used in:

• Houses
• Commercial buildings
• Timber-frame construction
• Agricultural structures
• Bridges
• Architectural projects

Large spans may require engineered timber such as glulam or LVL.

4. Columns and Posts

Timber posts and columns transfer vertical loads toward the foundation.

For these applications, factors such as compression, buckling, connections, moisture exposure, and durability can be important.

5. Wall Framing

Structural timber framing can form the load-bearing framework of walls.

This is particularly common in timber-frame and lightweight construction systems.

6. Bridges

Timber has a long history of use in bridge construction.

Modern timber bridges may use solid structural timber, glulam, or other engineered timber products depending on the design.

7. Agricultural Buildings

Structural timber can be used in:

• Barns
• Storage buildings
• Shelters
• Agricultural roof systems
• Other farm structures

The appropriate timber specification depends heavily on environmental exposure and expected loads.

8. Commercial Buildings

Timber construction is also used in commercial buildings, particularly where architects and engineers incorporate mass timber or engineered timber systems.

Structural Timber vs Non-Structural Timber

Feature	Structural Timber	Non-Structural Timber
Primary purpose	Load-bearing or structural function	Decorative or general-purpose applications
Grading	Usually subject to structural grading/classification	May use appearance or other grades
Strength requirements	Defined according to applicable standards	May not require structural classification
Defect requirements	Controlled according to grade	Requirements may focus more on appearance
Typical applications	Beams, joists, rafters, posts	Cladding, furniture, decorative work
Documentation	May require grading/classification documentation	Depends on product and market
Engineering use	Can be specified for structural design when compliant	Should not be assumed suitable for structural design

A visually attractive board is not necessarily structural timber.

Similarly, a timber with excellent natural durability is not automatically suitable as a load-bearing member.

Structural Timber vs Engineered Timber

Structural timber and engineered timber overlap but are not identical terms.

Structural timber describes timber intended or classified for structural use.

Engineered timber describes timber products manufactured through engineered processes such as laminating, bonding, or cross-layering.

Therefore, engineered timber can be structural timber, but structural timber does not necessarily have to be engineered.

For example:

• A graded solid-sawn beam can be structural timber.
• A glulam beam can be engineered structural timber.
• An LVL beam can be engineered structural timber.
• A decorative timber board is neither necessarily structural nor engineered.

How to Choose Structural Timber

Choosing structural timber should begin with the requirements of the project rather than the appearance of the timber.

1. Identify the Application

Determine whether the timber will be used for:

• Beam
• Column
• Joist
• Rafter
• Truss
• Wall framing
• Bridge
• Outdoor structure
• Other load-bearing component

2. Specify Dimensions

Provide exact:

• Thickness
• Width
• Length
• Quantity
• Required tolerances

For volume calculations, AtoZ Wood Company’s Timber CBM Calculator can help buyers estimate cubic-meter volume.

3. Specify the Grade

Do not simply ask for a particular species.

Where structural performance is required, specify the required structural grade or classification according to the applicable standard.

4. Check Moisture Requirements

Specify whether the timber needs to be:

• Air dried
• Kiln dried
• Supplied at a particular moisture range
• Suitable for interior conditions
• Suitable for exterior exposure

5. Consider Durability

For outdoor or moisture-exposed structures, durability becomes especially important.

Natural durability and preservative treatment may both be relevant, depending on the species and application.

6. Check Certification and Documentation

Depending on the market and project, buyers may require:

• Structural grading documentation
• Inspection reports
• Certificate of Origin
• Phytosanitary documentation
• FSC certification
• PEFC certification
• Treatment certificates
• Other market-specific documentation

The exact documents required depend on the destination country, product, species, and application.

Why Timber Species Alone Does Not Determine Structural Performance

One of the most common misconceptions in timber purchasing is that a strong species automatically equals strong structural timber.

Consider two pieces of the same species.

One may have:

• Large knots
• Significant grain deviation
• High moisture
• Checks or splits
• Poor dimensions

The other may have:

• Better grain
• Fewer defects
• Controlled moisture
• Appropriate dimensions
• A recognized structural grade

Although both come from the same species, their structural characteristics may differ.

This is why professional structural timber purchasing considers species + grade + dimensions + moisture + defects + standards + application.

Common Mistakes When Buying Structural Timber

1. Buying Only by Species Name
   
   As discussed above, species does not automatically determine structural grade.
2. Ignoring Moisture Content 

   Timber that is too wet for its intended application may experience additional movement as it dries.

3. Not Specifying the Grade 

   A buyer asking for “strong timber” leaves too much room for interpretation.
   A recognized grade or specification is much more useful.

4. Assuming Decorative Timber Is Structural 

   Appearance-grade timber is not automatically suitable for load-bearing construction.

5. Ignoring Defects 

   Large knots, severe grain deviation, decay, splits, and other defects can affect structural performance.

6. Assuming All Standards Are Interchangeable 

   A grading system used in one market may not directly correspond to another system.
   Always confirm which standard applies.

7. Buying Without Documentation 

   For commercial construction and international timber purchasing, appropriate documentation can help establish product specifications, origin, inspection status, and compliance requirements.

Structural Timber for International Buyers

A clear purchase specification should ideally include:

• Species
• Product type
• Grade
• Dimensions
• Lengths
• Moisture content
• Quantity
• Treatment requirements
• Packaging requirements
• Destination port
• Required documentation
• Applicable standards

For international orders, buyers may also need to consider import regulations, phytosanitary requirements, legality documentation, certification, inspection, and destination-country requirements.

A detailed specification reduces misunderstandings between the buyer and supplier.

AtoZ Wood Company supplies timber products for international buyers and can discuss product specifications, dimensions, quantities, processing requirements, and relevant documentation according to the order and destination market.

Structural Timber Dimensions and Volume

It is commonly purchased according to dimensions and cubic-meter volume.

For example, a buyer may specify:

100 mm × 200 mm × 6,000 mm

The total volume depends on the number of pieces ordered.

Buyers working with mixed dimensions can use the Timber Dimension Converter to convert common timber measurements.

A timber’s weight can also be useful when planning transportation, handling, and logistics. AtoZ Wood Company’s Timber Weight Calculator can assist with timber weight estimation.

For comparing characteristics across different species, the Wood Species Comparison tool can also be useful as an initial reference.

These tools are useful for estimation and comparison, but they should not replace engineering calculations or certified structural data.

What Makes Good Structural Timber?

There is no single characteristic that makes a piece of timber “good” for every structural application.

A suitable structural timber product generally needs to match the requirements of its intended use.

Important characteristics may include:

• Appropriate structural grade
• Adequate strength
• Suitable stiffness
• Controlled moisture content
• Appropriate dimensions
• Acceptable defects
• Suitable durability
• Correct treatment where required
• Traceable origin
• Appropriate documentation
• Compliance with applicable standards

The requirements for a roof rafter are not necessarily identical to those for a bridge beam or heavy timber column.

The application must therefore guide the specification.

Structural Timber and Sustainable Construction

Timber is a renewable construction material when forests are responsibly managed and harvested within appropriate legal and environmental frameworks.

Responsible timber sourcing can include:

• Legal forest management
• Controlled harvesting
• Reforestation and regeneration
• Traceability
• Protection of biodiversity
• Responsible labour practices
• Community engagement
• Certification where applicable

For international buyers, certification schemes such as FSC and PEFC can provide additional information about responsible forest management and supply-chain practices, depending on the specific certified product and claim.

However, sustainability certification and structural grading serve different purposes.

Certification relating to forest management does not itself establish structural strength.

Likewise, a structural grade does not by itself establish that timber came from a responsibly managed forest.

Both aspects may matter, but they answer different questions.

Conclusion

Structural timber is more than simply strong timber.

It is timber selected and specified according to the requirements of a structural application. Its performance can depend on species, grade, strength characteristics, moisture content, dimensions, grain, defects, durability, manufacturing, and applicable standards.

For buyers, one of the most important lessons is to avoid purchasing structural timber based solely on a species name. A complete specification should identify the product, dimensions, required grade, moisture condition, intended application, and relevant documentation.

For international timber procurement, clear specifications also help suppliers understand exactly what the buyer requires and reduce potential problems during production, inspection, shipping, and delivery.

AtoZ Wood Company supplies a range of timber products for international markets, with product specifications and documentation determined according to the species, product, order requirements, and destination market.

When structural timber is being considered for an actual building or engineered structure, the final selection, sizing, connections, and load calculations should always follow the applicable building standards and be verified by the responsible structural professional.

Understanding timber sizes is essential when buying wood for construction, furniture, flooring, decking, manufacturing, and international timber trade. Whether you are purchasing hardwood boards, ordering softwood lumber, specifying structural beams, or calculating the volume of a timber shipment, knowing how wood is measured can help you avoid costly mistakes.

Timber is commonly sold according to its thickness, width, and length. However, the dimensions stated by a supplier may not always match the measurements you obtain with a tape measure. Differences can occur because of nominal sizing, rough sawing, drying, planing, machining, and regional measurement standards.

For example, a board described as 2 × 4 inches in the North American lumber market may have actual dressed dimensions of approximately 1½ × 3½ inches. This difference is particularly important when ordering wood for a specific project or comparing timber prices between suppliers.

This comprehensive guide explains timber dimensions, standard wood sizes, nominal and actual measurements, metric and imperial conversions, common timber profiles, and how to calculate timber volume accurately.

What Are Timber Sizes and Dimensions?

Timber dimensions describe the physical measurements of a piece of wood. The three primary dimensions are:

1. Thickness – The distance from one face of the board to the opposite face.
2. Width – The measurement across the board’s surface.
3. Length – The distance from one end of the timber to the other.

For example, a timber board measuring 50 × 150 × 3,000 mm has:

Timber can be supplied as rough-sawn, kiln-dried, air-dried, planed, moulded, or fully finished material. The manufacturing process can affect the final dimensions.

When purchasing wood, it is important to establish whether the quoted measurements refer to the rough-sawn size, nominal size, or finished actual size.

Nominal Timber Size vs Actual Timber Size

One of the most common sources of confusion in timber purchasing is the difference between nominal and actual dimensions.

What Is Nominal Size?

A nominal size is the traditional or commercial name used to describe a piece of lumber. In some markets, the nominal dimension refers to the approximate size before drying and surfacing.

For example:

• Nominal size: 2 × 4 inches
• Actual dressed size: approximately 1½ × 3½ inches

The nominal size is used for identification, pricing, and product classification, while the actual size describes the dimensions of the finished piece.

What Is Actual Size?

Actual size is the physical measurement of the timber after manufacturing processes such as:

• Drying or seasoning
• Planing
• Surfacing
• Edge trimming
• Calibration
• Moulding

The finished dimensions may be smaller than the original rough-sawn dimensions because wood is removed during machining and may shrink during drying.

Important: Nominal-to-actual differences are not universal across all timber products. Hardwood boards, rough-sawn African timber, engineered wood, reclaimed lumber, and custom-machined products may follow different specifications.

Standard North American Lumber Sizes

In North America, many softwood lumber products are sold using nominal dimensions in inches. These products are commonly used for framing, construction, carpentry, and general building applications.

The following table provides common nominal and actual dressed dimensions.

Standard 1-Inch Nominal Lumber

Standard 2-Inch Nominal Lumber

These are commonly referenced dry dressed dimensions for North American softwood lumber. Actual dimensions can vary depending on the applicable standard, moisture condition, surfacing, and manufacturing tolerances.

Standard Larger Lumber Sizes

These sizes are often encountered in construction, joinery, structural applications, and general woodworking. However, the appropriate size depends on the timber species, grade, loading conditions, span, and applicable building requirements.

Timber Sizes in Millimetres

Metric measurements are widely used in Europe, Africa, Asia, Australia, and many international timber markets. Timber is commonly specified in millimetres, centimetres, or metres.

Examples include:

• 25 × 100 × 2,400 mm
• 38 × 89 × 3,000 mm
• 50 × 150 × 4,000 mm
• 75 × 225 × 6,000 mm
• 100 × 200 × 3,600 mm

A metric timber specification is generally written as:

Thickness × Width × Length

For example:

50 × 150 × 3,000 mm

This means:

• Thickness: 50 mm
• Width: 150 mm
• Length: 3,000 mm

However, some suppliers or technical drawings may list width before thickness. Always confirm the order of dimensions before placing an order.

Common Metric Timber Dimensions

The following are examples of frequently requested dimensions. They are not universal mandatory sizes for every species or market.

The correct dimensions depend on the timber species, intended application, strength requirements, available log sizes, and the supplier’s production capabilities.

Rough-Sawn Timber vs Planed Timber Dimensions

The manufacturing process has a direct effect on timber measurements.

1. Rough-Sawn Timber

Rough-sawn timber is cut from a log using a sawmill. Its surfaces may retain:

• Saw marks
• Uneven texture
• Minor dimensional variations
• Natural edges
• Small machining irregularities

Rough-sawn timber is often supplied for structural work, industrial applications, packaging, outdoor projects, and further processing.

For example, a supplier may quote a rough-sawn board as:

50 × 150 × 3,000 mm

The final dimensions should be confirmed because sawing tolerances and drying may affect the measurements.

2. Planed Timber

Planed timber is machined to create smoother and more uniform surfaces. Depending on the process, it may be described as:

• Sawn and planed
• S4S – surfaced on four sides
• S2S – surfaced on two sides
• Calibrated timber
• Moulded timber

Planing removes material from the faces or edges. Consequently, a timber piece that begins as a larger rough-sawn section may finish at a smaller dimension.

3. Kiln-Dried Timber

Kiln drying reduces moisture content under controlled conditions. As moisture leaves the wood, the timber may shrink, particularly when its moisture content falls below the fibre saturation point.

The amount of shrinkage depends on:

• Wood species
• Grain direction
• Initial moisture content
• Final moisture content
• Board thickness
• Drying schedule
• Grain orientation

For precision projects, the required moisture content and finished dimensions should be specified in advance.

Standard Timber Thicknesses

Timber thickness is an important specification for structural performance, machining, appearance, and end-use suitability.

Some commonly traded thicknesses include:

These are common reference thicknesses rather than guarantees of availability. Certain hardwoods may be supplied in specialized thicknesses based on log recovery, customer specifications, and mill capabilities.

Standard Timber Widths

Timber width affects the usable surface area, visual appearance, stability, and material yield.

Common widths include:

Wide timber boards and slabs may be more difficult to source consistently, especially in dense hardwood species. Their availability depends on log diameter, sawing method, grade, drying requirements, and allowable defects.

Standard Timber Lengths

Timber length is normally specified in millimetres, metres, feet, or inches.

Common commercial lengths include:

• 1,800 mm
• 2,400 mm
• 3,000 mm
• 3,600 mm
• 4,000 mm
• 4,800 mm
• 5,000 mm
• 6,000 mm

In some markets, lumber is sold in standard imperial lengths such as 6, 8, 10, 12, 14, and 16 feet. Availability varies according to the product category and supplier.

Timber Length Conversion Table

Note: Exact metric conversions may produce decimal values. Commercial timber is often rounded or specified according to the supplier’s production and grading standards.

Common Timber Profiles and Their Measurements

Timber is available in different profiles depending on its purpose. A board, beam, post, batten, slab, or moulding may have very different dimensions.

1. Timber Boards

Boards are generally thinner than heavy structural timbers and are used for:

• Furniture
• Flooring
• Wall cladding
• Shelving
• Doors
• Interior finishing
• General woodworking

Example specification:

25 × 150 × 3,000 mm

2. Timber Battens

Battens are narrow strips of timber commonly used for:

• Roofing support
• Wall framing
• Fencing
• Cladding support
• Interior construction
• Packaging

Example specification:

25 × 50 × 2,400 mm

3. Timber Beams

Beams are larger timber sections used for structural or heavy-duty applications.

Example specification:

100 × 200 × 4,000 mm

The suitability of a beam depends on its species, grade, strength properties, moisture condition, span, load, and structural design.

4. Timber Posts

Posts are generally square or rectangular sections used for:

• Fencing
• Landscaping
• Structural supports
• Outdoor construction
• Garden structures

Example specification:

100 × 100 × 3,000 mm

5. Timber Slabs

Slabs are wide sections of wood, often cut from large logs. They may retain natural edges and are frequently used for:

• Dining tables
• Conference tables
• Countertops
• Decorative furniture
• Premium interior projects

Slab dimensions vary considerably. A supplier may quote a slab using:

Thickness × Width × Length

For natural-edge slabs, the width may vary along the length. The supplier should specify whether the quoted width is the minimum, maximum, or average.

Hardwood Timber Sizes vs Softwood Timber Sizes

Hardwood and softwood products may be sold using different sizing conventions.

Hardwood Timber

Hardwood is commonly supplied as:

• Rough-sawn boards
• Square-edged boards
• Boules
• Live-edge slabs
• Sawn scantlings
• Beams
• Flooring blanks
• Furniture components

Hardwood dimensions may be customized according to the species and intended application.

Common hardwood applications include:

• Furniture
• Flooring
• Decking
• Shipbuilding
• Heavy construction
• Doors and windows
• Outdoor structures
• Decorative panels

Softwood Timber

Softwood is commonly used for:

• Construction framing
• Roofing
• Packaging
• Furniture
• Joinery
• Cladding
• General building work

In markets such as North America, softwood lumber is frequently sold using standardized nominal dimensions. Other markets may use metric dimensions or project-specific specifications.

Do not assume that a hardwood board and a softwood board with the same stated size have identical actual dimensions. Always confirm the product specification with the supplier.

How to Measure Timber Correctly

Accurate timber measurement is essential when buying wood, calculating volume, preparing cutting lists, or checking delivered goods.

Step 1: Measure the Thickness

Use a tape measure, ruler, or digital caliper to measure the distance between the two broad faces of the timber.

For rough-sawn material, measure at multiple points because the thickness may vary.

Step 2: Measure the Width

Measure across the face of the board, perpendicular to its length.

For irregular or natural-edge slabs, measure the width at several points and record the method used.

Step 3: Measure the Length

Measure from one end of the timber to the other.

If the ends are irregular, clarify whether the measurement refers to:

• Overall length
• Usable length
• Shortest length
• Longest length
• Nominal length

Step 4: Record the Units

Write the measurements consistently.

For example:

• 50 × 150 × 3,000 mm
• 5 × 15 × 300 cm
• 2 × 6 × 10 ft

Avoid mixing inches, feet, millimetres, and metres without converting them first.

Step 5: Check the Finished Specification

Before ordering, confirm whether the measurements are:

• Rough-sawn
• Green or freshly sawn
• Kiln-dried
• Planed
• S4S
• Calibrated
• Finished dimensions

This distinction can affect both the quantity and the suitability of the timber for your project.

How to Calculate Timber Volume

Timber volume is commonly measured in cubic metres (m³). This is especially important for commercial timber orders, container shipments, inventory management, and international trade.

The basic formula is:

Volume=Thickness×Width×Length\text{Volume} = \text{Thickness} \times \text{Width} \times \text{Length}

All measurements must be expressed in metres when calculating cubic metres.

Example: Calculate the Volume of One Timber Board

Suppose a board measures:

• Thickness: 50 mm
• Width: 150 mm
• Length: 3,000 mm

Convert the dimensions into metres:

• 50 mm = 0.05 m
• 150 mm = 0.15 m
• 3,000 mm = 3 m

Then:

0.05×0.15×3=0.0225 m30.05 \times 0.15 \times 3 = 0.0225 \text{ m}^3

Therefore, the volume of one board is:

0.0225 m³

Example: Calculate the Volume of 100 Boards

If one board has a volume of 0.0225 m³:

0.0225×100=2.25 m30.0225 \times 100 = 2.25 \text{ m}^3

The total volume is:

2.25 m³

Timber Volume Calculation Table

These calculations assume uniform rectangular timber pieces and use the stated dimensions.

Calculate Timber Volume with an Online Tool

For faster calculations, use the Timber CBM Calculator.

This tool can help estimate the cubic metre volume of timber based on dimensions and quantity. It is useful for preparing material estimates and checking timber order calculations.

For commercial orders, remember that calculated geometric volume may differ from the final invoiced or shipped volume if the supplier uses different measurement rules, actual dimensions, package measurements, or agreed commercial terms.

Timber Dimension Conversion: Inches, Feet, Millimetres and Metres

International timber trade often involves different measurement systems. A buyer in one country may specify timber in inches and feet, while a supplier may quote dimensions in millimetres and metres.

Basic Conversion Factors

Common Timber Dimension Conversions

These are direct mathematical conversions of the stated dimensions. They should not be confused with the actual finished sizes of nominal North American lumber.

Convert Timber Dimensions Online

Use the Timber Dimension Converter to convert timber measurements between common units.

This can be useful when:

• Comparing supplier quotations
• Preparing international purchase orders
• Converting architectural specifications
• Checking imported timber dimensions
• Preparing cutting lists
• Comparing imperial and metric lumber sizes

Timber Weight and Its Relationship to Dimensions

Timber dimensions determine volume, while wood density helps estimate weight.

The approximate formula is:

Weight=Volume×Density\text{Weight} = \text{Volume} \times \text{Density}

For example, if a timber shipment has a volume of 2 m³ and the assumed density is 600 kg/m³:

2×600=1,200 kg2 \times 600 = 1,200 \text{ kg}

The estimated weight would be:

1,200 kg

However, timber weight varies according to:

• Species
• Moisture content
• Density
• Grain structure
• Defects
• Treatment
• Drying condition
• Packaging

Two timber products with identical dimensions may have different weights because they are made from different species or have different moisture contents.

Estimate Timber Weight Online

Use the Timber Weight Calculator to estimate the weight of timber based on its volume and density.

For shipping and logistics, calculator results should be treated as estimates unless the actual product weight has been verified. Packaging, pallets, straps, moisture, and container materials may add to the total shipment weight.

What Timber Dimensions Should You Include in a Purchase Order?

A clear timber purchase order should contain more than just the product name and quantity.

For accurate quotations, include the following:

For irregular products such as slabs, additional specifications may be necessary:

• Minimum width
• Maximum width
• Minimum thickness
• Natural edge requirements
• Length tolerance
• Moisture content
• Surface finish
• Cracks and defect allowances
• Kiln-drying requirements

Why Clear Dimensions Matter

Incorrect or incomplete dimensions can lead to:

• Wrong quantity calculations
• Incorrect CBM estimates
• Higher shipping costs
• Material shortages
• Cutting losses
• Project delays
• Disputes between buyers and suppliers

For international timber orders, it is advisable to obtain a written product specification and confirm how the dimensions will be measured before production begins.

Common Mistakes When Buying Timber by Size

1. Confusing Nominal and Actual Dimensions

A nominal 2 × 4 may not measure 2 × 4 inches after drying and surfacing.

Solution: Ask for the actual finished dimensions.

2. Assuming Every Supplier Uses the Same Standards

Different countries and suppliers may use different sizing conventions.

Solution: Confirm the measurement system and applicable product standard.

3. Ignoring Moisture Content

Timber can shrink or change dimensions as it dries.

Solution: Specify the required moisture condition for the intended use.

4. Using Nominal Dimensions to Calculate Volume

Calculating CBM using nominal sizes instead of the agreed billable or actual dimensions may produce incorrect results.

Solution: Confirm whether volume is calculated using nominal, rough-sawn, finished, or measured dimensions.

5. Forgetting Processing Allowances

Planing and machining can reduce thickness and width.

Solution: Specify whether the timber is supplied rough-sawn or finished.

6. Measuring Irregular Slabs Incorrectly

Natural-edge slabs may not have uniform widths.

Solution: Agree on the method for measuring usable area, average width, or minimum width.

7. Not Confirming Length Tolerances

A timber order requiring exact lengths may be affected by trimming, end defects, or production tolerances.

Solution: Specify minimum usable length and acceptable tolerances.

How to Choose the Right Timber Size for Your Project

The correct timber size depends on the intended application rather than appearance alone.

For Furniture

Consider:

• Finished thickness
• Width and length
• Stability
• Moisture content
• Surface finish
• Machining allowance
• Grain direction

Furniture manufacturers may purchase thicker rough-sawn boards so they can plane and machine them to the required finished dimensions.

For Flooring

Consider:

• Thickness
• Width
• Length
• Tongue-and-groove profile
• Wear layer
• Moisture content
• Stability
• Installation method

For Decking

Consider:

• Board thickness
• Board width
• Length
• Surface profile
• Slip resistance
• Durability
• Moisture condition
• Fixing method

For Structural Timber

Consider:

• Cross-sectional dimensions
• Species
• Grade
• Strength class
• Moisture content
• Span
• Loads
• Connection details
• Local building requirements

A larger timber section is not automatically suitable for every structural application. Structural sizing should be determined by a qualified professional using the relevant design standards.

For Export Timber Orders

Consider:

• Agreed product dimensions
• Tolerances
• Quantity
• CBM calculation method
• Packaging
• Moisture content
• Required certificates
• Destination-country requirements
• Shipping and container limits

Timber Dimensions and International Trade

Timber is traded globally in a variety of formats, including logs, sawn boards, beams, slabs, flooring blanks, decking boards, and engineered wood products.

Buyers may request dimensions based on their local market or manufacturing requirements. A supplier must therefore understand the difference between:

• Nominal size
• Rough-sawn size
• Actual finished size
• Planed size
• Calibrated size
• Minimum size
• Average size
• Custom dimensions

For example, a buyer may request:

Iroko timber, 50 × 150 × 3,000 mm, kiln-dried, planed, with a specified moisture content.

Another buyer may request:

Iroko rough-sawn boards, 2 × 6 × 10 ft, with agreed tolerances.

Although these specifications may appear similar, the finished dimensions, processing requirements, and total volume may differ.

For this reason, international timber buyers should always request a detailed quotation that identifies the product form, dimensions, quantity, grade, moisture condition, and measurement basis.

Frequently Asked Questions About Timber Sizes

What are the standard sizes of timber?

Common timber sizes include 25 × 50 mm, 25 × 100 mm, 50 × 100 mm, 50 × 150 mm, 75 × 150 mm, and 100 × 200 mm. However, standard sizes vary by country, timber species, product type, and manufacturing requirements.

Is a 2 × 4 actually 2 × 4 inches?

Not usually when referring to standard dry dressed North American softwood lumber. A nominal 2 × 4 commonly has actual dimensions of approximately 1½ × 3½ inches. Rough-sawn, full-sawn, and specialty timber may have different dimensions.

What is the difference between rough-sawn and planed timber?

Rough-sawn timber retains saw marks and may have greater dimensional variation. Planed timber has been machined to create smoother and more uniform surfaces, usually reducing its original dimensions.

How do I calculate the CBM of timber?

Multiply thickness, width, and length in metres, then multiply by the number of pieces.

Total CBM=T×W×L×Q\text{Total CBM} = T \times W \times L \times Q

Where:

• T = thickness in metres
• W = width in metres
• L = length in metres
• Q = quantity

What is the most common timber length?

Common commercial lengths include 2.4 m, 3 m, 3.6 m, 4 m, 4.8 m, and 6 m. Availability depends on the timber species, market, product type, and supplier.

Are timber dimensions the same in every country?

No. Timber sizing conventions differ between countries and product categories. Some markets use imperial nominal sizes, while others use metric dimensions or customized specifications.

Does timber shrink after drying?

Yes. Wood generally shrinks as it loses moisture below the fibre saturation point. The amount of shrinkage depends on species, grain direction, initial and final moisture content, and drying conditions.

How do I order timber with accurate dimensions?

Specify the wood species, product type, thickness, width, length, quantity, moisture condition, surface finish, grade, and acceptable tolerances. Also confirm how the supplier calculates volume and verifies dimensions.

Final Thoughts

Understanding timber sizes, standard dimensions, and measurements is essential for making informed purchasing decisions and avoiding errors in woodworking, construction, furniture production, and international timber trade.

Before ordering timber, always confirm:

• Whether the size is nominal or actual
• Whether the timber is rough-sawn or planed
• The thickness, width, and length
• The moisture condition
• The acceptable dimensional tolerances
• The unit of measurement
• The volume calculation method
• The required product grade and finish

Accurate dimensions help buyers compare quotations, calculate timber volume, estimate weight, plan production, and manage shipping requirements more effectively.

For convenient timber calculations, use AtoZ Wood Company’s online tools:

• Timber CBM Calculator – Calculate timber volume in cubic metres.
• Timber Dimension Converter – Convert timber measurements between common units.
• Timber Weight Calculator – Estimate timber weight using volume and density.

Need timber cut to specific dimensions? AtoZ Wood Company supplies a range of hardwood and softwood timber products for international buyers. When requesting a quotation, provide the species, dimensions, quantity, and destination port so the appropriate product specification and pricing can be prepared.

If you’re looking for the right hardwood species for an outdoor deck, patio, walkway, or other exterior application, both are wonderful choices. Both woods are exceptionally dense, durable and resist weather elements extremely well. The most important difference between Ipe and Cumaru is that Cumaru timber is slightly cheaper than Ipe and more readily available.

At AtoZ Wood Company, we are committed to ensuring that our customers know everything there is to know about cumaru vs Ipe to make an informed decision.

What Is Ipe?

Often called Brazilian Walnut, it is one of the most sought-after wood species for hardwood decking. Renowned for its attractive rich brown color, remarkable strength, and natural resistance to moisture and insects, Ipe is considered the gold standard for outdoor projects, particularly decking.

Freshly sawn Ipe is typically rich brown with reddish undertones. Exposure to sunlight causes it to develop an attractive silver-gray patina over time. Its tight, interlocked grain and smooth surface make it suitable for contemporary and traditional designs.

It is naturally saturated with oils, making it resistant to rot, insects, and moisture. Its high density makes it resist general wear.

What Is Cumaru?

It is commonly known as Brazilian Teak, is a North American tropical hardwood known for its excellent outdoor durability. Cumaru is nearly as dense and durable as Ipe, making it a long-lasting decking material.

It has a golden, reddish-brown heartwood with a varying, tight grain pattern that can change from board to board. Like Ipe, Cumaru evolves to a silvery-gray patina due to exposure.

The high density makes it resistant to wear, decay, insects, moisture, and heavy traffic (decking). It is almost 20% to 30% cheaper than Ipe, making it an excellent alternative.

Cumaru vs Ipe: Key Differences

The most noticeable difference between the two hardwoods is often appearance and price, as both share similar outdoor performance.

Durability: Ipe is one of the most durable hardwoods with excellent outdoor resistance and is considered the benchmark for hardwood decking. Cumaru is also extremely durable and resistant to insects, moisture and heat. Both woods can last decades when properly installed and maintained.

Color and grain: Here lies the main difference. Ipe features a deeper, more uniform brown undertone, while Cumaru’s color can range from bright golden to reddish brown with distinct variation.

Hardness: Both are among the hardest woods in the world. When closely compared, Ipe is slightly harder and denser with better wear resistance. It also means that it can be difficult to cut, drill, and use.

Price: This is another major difference. Ipe is generally pricier than Cumaru because of its high demand, richer appearance, consistent performance, and durability. Cumaru is slightly cheaper and offers better value for budget-conscious projects.

Maintenance: Both timber species require low maintenance compared to many other hardwood decking options. Neither requires chemical treatment or staining and remains structurally sound for many decades. A UV-protective hardwood finish can help preserve the original color, preventing it from turning gray.

Which Hardwood Is Better for Decking?

Both are equally great. The better choice depends on your preferences and budget.

Choose Ipe if you want a rich, consistent look with maximum durability and long-term performance. It is particularly favored for premium residential decks, commercial spaces, pool decks, and outdoor projects where exceptional longevity is a priority and budget is not a primary concern.

Choose Cumaru if you want great durability and a classic appearance at a more cost-effective price. It is generally favored for homes and other residential or low-budget commercial outdoor decking projects.

The performance and lifespan of both woods depend on installation quality and periodic maintenance.

Appearance Matters, Too

Your deck or patio is more than a durable surface; it is a major part of your landscaping and should be made to impress. Ipe’s darker, premium tones can give your project an upscale appearance, while Cumaru’s warmer appearance can offer a more cosy and inviting vibe.

Keep in mind that no two boards of either hardwood species are exactly alike. Their natural color variations are what make these woods so popular and distinctive.

Final Verdict: Cumaru or Ipe?

The ultimate choice depends on your particular preferences, goals, and budget. Ipe is slightly more durable and attractive (some would say) and also more expensive. Cumaru is the best value-for-money option with excellent durability, beauty, and outdoor performance.

If you are confused, just go with the option that appears better for your project and fits your budget. At AtoZ Wood Company, we are always ready to help you find the right wood for your next woodworking project. From selection and purchase to delivery, we ensure a smooth timber-buying experience for every customer. Whether you’re ready to buy or need support, visit https://atozwoodcompany.com/ to explore our collection or contact us.