Tanalised Treated Timber 75 x 100mm 2.4m – 4×3 Timber
Tanalised Treated Timber 75 x 100mm 2.4m is a substantial pressure-treated softwood section suitable for outdoor construction, landscaping and general building projects. It is commonly referred to as 4×3 timber, based on its traditional approximate imperial dimensions of 4 inches by 3 inches.
The 75 x 100mm section offers greater thickness than standard 4×2 timber, making it suitable for projects requiring a chunkier, more substantial timber profile. Its convenient 2.4-metre length is straightforward to transport, store and manoeuvre while providing enough material for many garden, landscaping and building applications.
The timber has undergone a controlled pressure-treatment process to provide additional protection against fungal decay and wood-destroying insects. This improves its durability compared with untreated softwood when the product is correctly specified, installed and maintained in suitable external conditions.
Product dimensions
The nominal product dimensions are:
- Metric section: 75mm x 100mm
- Common imperial name: 4×3 timber
- Length: 2.4m
- Material: Treated softwood
- Treatment: Pressure treated or tanalised
- Suitable for: Building, landscaping and outdoor projects
The common name 4×3 is a traditional trade description rather than an exact imperial conversion. Use the stated metric dimensions when planning, measuring and cutting the timber.
What is tanalised timber?
Tanalised timber is softwood that has been treated with wood preservative using a controlled vacuum and pressure process. This allows the preservative to penetrate further into the wood than an ordinary surface-applied treatment.
The treatment helps protect the timber against fungal decay and attacks from wood-destroying insects. It can help extend the product’s service life when the timber is used in an appropriate external environment.
Pressure treatment does not make the timber entirely waterproof or maintenance-free. The wood can still absorb and release moisture, resulting in natural movement, shrinkage, surface checking, weathering and gradual colour changes.
Cutting, drilling or notching the wood can expose internal timber that may not have received the same level of preservative protection. Apply a compatible end-grain wood preservative to all freshly exposed areas during installation.
Common uses for 4×3 treated timber
The substantial 75 x 100mm section is suitable for a wide variety of garden, landscaping and general building projects.
Depending on its strength grade and the project specification, possible applications include:
- Outdoor timber frameworks
- Garden structures and features
- Pergolas and sheltered structures
- Landscaping projects
- Timber supports and bearers
- Agricultural and equestrian projects
- Raised garden structures
- External carpentry and joinery
- General repair and maintenance work
- Bespoke outdoor structures
- Heavy-duty garden edging
- Load-bearing applications where correctly graded
Where the timber will carry structural loads, confirm that it has the correct strength classification. Tanalised timber should not automatically be assumed to be C16 or C24 unless the product is specifically marked and sold with that grade.
The required span, loading, support spacing, connections and fixing arrangement should be determined by a suitably competent person for structural applications.
Benefits of the 2.4m length
The 2.4-metre length is convenient for many everyday building, landscaping and garden projects. It is easier to transport, store and handle than longer timber while still providing a useful amount of material.
The timber can be installed as a complete length or cut into multiple smaller components. Preparing a cutting schedule before beginning work can help minimise waste and make efficient use of each piece.
Its substantial cross-section means its weight will vary depending on moisture content. Suitable handling procedures should still be followed, especially when moving multiple lengths together.
Benefits of pressure-treated softwood
Pressure treatment provides several practical advantages for timber intended for appropriate outdoor use:
- Additional protection against fungal decay
- Protection against wood-destroying insects
- Improved durability compared with untreated softwood
- Suitable for many external projects
- Useful for landscaping and garden construction
- Can be cut and worked using suitable tools
- Practical for repair and maintenance work
- Suitable for professional and DIY projects
The correct treatment or use class must still be selected for the intended environment. Timber used in direct ground contact or exposed to persistent moisture may require a particular treatment specification.
Natural characteristics of timber
Timber is a natural material, so individual lengths will vary in grain pattern, shade, knots and surface texture. These differences are expected and contribute to the wood’s natural appearance.
Knots, resin pockets, minor splits and surface checking may be present. These characteristics are not automatically product defects, although their suitability will depend on the intended application and any relevant grading requirements.
Pressure treatment introduces additional moisture into the timber. As the wood dries, some shrinkage, twisting, bowing or cupping may occur. Correct storage and installation can help manage this natural movement.
Newly treated timber may initially have a green or brown appearance depending on the preservative system used. Its colour will generally fade and weather gradually following outdoor installation.
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 4×3 is an approximate imperial description rather than a guarantee of exact finished measurements. Customers requiring precise dimensions 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 that requires close-fitting joints or accurate dimensions.
Cutting and installation
Use suitable woodworking tools fitted with sharp blades when cutting or drilling the timber. Wear protective gloves, eye protection and appropriate respiratory protection while handling, sawing or sanding treated wood.
Complete cutting work in a well-ventilated area and avoid breathing timber dust. Sawdust and offcuts should be collected and disposed of responsibly. Pressure-treated wood must not be burned on domestic fires, in wood-burning appliances or on garden bonfires.
Apply a suitable end-grain preservative to every cut end, drilled hole and notch. Use corrosion-resistant fixings compatible with treated timber, especially in external or regularly damp environments.
Where the timber forms part of a load-bearing structure, 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 suitable intervals. Protect it from prolonged saturation while allowing sufficient airflow around each length.
For visible outdoor applications, a compatible wood stain, oil or protective coating may be applied after the timber has dried sufficiently. Follow the coating manufacturer’s preparation and moisture-content instructions.
Inspect external timber periodically, paying particular attention to joints, cut ends, fixing points and areas where water might collect.
Key benefits
- Substantial 75 x 100mm timber section
- Commonly known as 4×3 timber
- Convenient 2.4m length
- Pressure treated against decay and insects
- Suitable for garden structures and landscaping
- Useful for outdoor frameworks and supports
- Easier to transport than longer timber lengths
- Can be cut for different project requirements
- More durable than untreated softwood
- Suitable for trade and DIY construction
Tanalised Treated Timber 75 x 100mm 2.4m – 4×3 Timber provides a substantial yet manageable section for outdoor frameworks, garden structures, landscaping and general building projects. Always confirm its exact dimensions, treatment level and strength grade against the requirements of the intended application before installation.
