Tanalised Treated Timber 47 x 100mm 4.8m – 4×2 Timber
Tanalised Treated Timber 47 x 100mm 4.8m is a versatile pressure-treated softwood section suitable for outdoor construction, landscaping and general building projects. It is commonly referred to as 4×2 timber, based on its traditional approximate imperial dimensions of 4 inches by 2 inches.
The 47 x 100mm section is one of the most popular timber sizes for general construction, landscaping and DIY work. Its useful 4.8-metre length provides flexibility for larger frameworks and can help reduce the number of joints required when compared with shorter timber lengths.
The timber has undergone a controlled pressure-treatment process to provide additional protection against fungal decay and wood-destroying insects. This treatment improves its durability compared with untreated softwood when the product is correctly specified, installed and maintained in an appropriate environment.
Product dimensions
The nominal product dimensions are:
- Metric section: 47mm x 100mm
- Common imperial name: 4×2 timber
- Length: 4.8m
- Material: Treated softwood
- Treatment: Pressure treated or tanalised
- Suitable for: Building, landscaping and outdoor projects
The name 4×2 is a traditional trade description and should not be treated as an exact imperial conversion. Use the stated metric measurements when planning, cutting and installing the timber.
What is tanalised timber?
Tanalised timber is softwood treated with preservative through a controlled vacuum and pressure process. This encourages the treatment to penetrate deeper into the timber than a standard brush-applied surface coating.
The preservative helps protect the wood against fungal decay and attacks by wood-destroying insects. It makes the timber suitable for many external, exposed and moisture-prone applications.
Pressure treatment does not make timber completely waterproof or maintenance-free. The wood can still absorb and release moisture, leading to natural movement, shrinkage, surface checking, weathering and gradual colour changes.
Cutting, drilling or notching the timber exposes internal wood that may not have received the same level of protection. Treat all newly exposed areas with a suitable end-grain wood preservative during installation.
Common uses for 4×2 treated timber
The 47 x 100mm section is highly adaptable and can be used across many outdoor and general construction projects.
Depending on its strength grade and the project specification, possible applications include:
- Outdoor timber frameworks
- Garden sheds and buildings
- Landscaping projects
- Timber supports and bearers
- Garden screens and dividers
- Agricultural and equestrian structures
- Raised garden features
- External carpentry and joinery
- General repair and maintenance work
- Bespoke outdoor structures
- Load-bearing members where correctly graded
- Garden and DIY projects
Where structural performance is required, confirm that the timber has the correct strength classification. Tanalised timber should not automatically be assumed to be C16 or C24 unless it is specifically marked and sold with that grade.
A suitably competent person should determine the required span, support spacing, loading, connections and fixings for structural applications.
Benefits of the 4.8m length
The 4.8-metre length is useful for larger garden and construction projects. Where suitable for the design, it may create longer continuous runs and reduce the number of joints within the framework.
It can also be cut into multiple shorter pieces. Planning the cuts before work begins can help minimise waste and ensure the full length is used efficiently.
Site access should be considered before ordering. Make sure there is sufficient space to unload, carry, store and manoeuvre a 4.8m length safely.
Timber weight will vary depending on its moisture content. Appropriate lifting assistance and safe handling procedures should be used when moving several lengths or positioning the timber at height.
Natural characteristics of timber
Timber is a natural product, so every length will have variations in grain, colour, knots and surface texture. These differences are normal and contribute to its natural appearance.
Knots, resin pockets, minor splits and surface checking may be present. These characteristics do not automatically indicate a defect, although their suitability will depend on the intended use and any applicable grading standards.
Pressure treatment introduces additional moisture into the timber. As the wood dries, some shrinkage, twisting, bowing or cupping may occur. Suitable storage, acclimatisation and installation can help manage this natural movement.
Newly treated timber may initially appear green or brown depending on the treatment system used. Its colour will normally fade and weather gradually following outdoor exposure.
Important sizing information
Please note: Timber dimensions are nominal and may vary slightly due to machining, pressure treatment, moisture content and the natural movement of the wood.
The common name 4×2 is an approximate imperial description rather than a guarantee of exact finished dimensions. Customers requiring precise measurements should check the timber before installation or contact us to confirm the current stock specification.
Allow the timber to acclimatise where appropriate before completing work involving precise joints or close-fitting sections.
Cutting and installation
Use suitable woodworking tools fitted with sharp blades when cutting or drilling this timber. Wear protective gloves, eye protection and appropriate respiratory protection when handling, sawing or sanding treated wood.
Work in a well-ventilated area and avoid breathing timber dust. Sawdust and offcuts should be collected and disposed of responsibly. Pressure-treated timber must not be burned on domestic fires, in wood-burning appliances or on garden bonfires.
Apply a compatible end-grain preservative to every cut end, drilled hole and notch. Use corrosion-resistant fixings suitable for treated timber, particularly in external or regularly damp environments.
Where the timber forms part of a load-bearing structure, all supports, connections and fixings must follow the approved design and be suitable for the anticipated loads.
Storage and maintenance
Store the timber flat, raised above the ground and supported at regular intervals. Protect it from prolonged saturation while allowing air to circulate around the lengths.
A compatible wood stain, oil or protective coating may be applied to visible external timber after it has dried sufficiently. Follow the coating manufacturer’s instructions regarding preparation and moisture content.
Inspect outdoor timber periodically, paying particular attention to cut ends, joints, fixing points and horizontal areas where water may collect.
Key benefits
- Versatile 47 x 100mm timber section
- Commonly known as 4×2 timber
- Supplied in a practical 4.8m length
- May reduce joints in larger frameworks
- Pressure treated against decay and insects
- Suitable for outdoor frameworks and landscaping
- Useful for garden and agricultural structures
- Can be cut to meet different project requirements
- More durable than untreated softwood
- Suitable for professional and DIY construction
Tanalised Treated Timber 47 x 100mm 4.8m – 4×2 Timber provides a versatile section and useful length for outdoor frameworks, landscaping, garden structures and general building projects. Always confirm its dimensions, treatment level and strength grade against the requirements of the intended application before installation.
