Tanalised Treated Timber 47 x 175mm 3.6m – 7×2 Timber
Tanalised Treated Timber 47 x 175mm 3.6m is a versatile pressure-treated softwood section for outdoor construction, landscaping and general building projects. It is commonly referred to as 7×2 timber, based on its traditional approximate imperial dimensions of 7 inches by 2 inches.
Its 175mm depth provides a substantial timber section, while the convenient 3.6-metre length makes it suitable for projects where longer 4.8m or 6.0m pieces are not required. It can be used as a full length or cut into smaller components to meet the requirements of the job.
The timber has undergone a controlled pressure-treatment process to provide additional protection against fungal decay and wood-destroying insects. This helps improve its durability compared with untreated softwood when correctly specified, installed and maintained in suitable external environments.
Product dimensions
The nominal product dimensions are:
- Metric section: 47mm x 175mm
- Common imperial name: 7×2 timber
- Length: 3.6m
- Material: Treated softwood
- Treatment: Pressure treated or tanalised
- Suitable for: Building, landscaping and outdoor projects
The common name 7×2 is a traditional trade description rather than an exact imperial conversion. Use the stated metric dimensions when measuring and planning your project.
What is tanalised timber?
Tanalised timber is softwood that has been impregnated with wood preservative using a controlled vacuum and pressure process. This method allows the preservative to penetrate deeper into the material than a basic brush-applied surface treatment.
The treatment helps protect the timber against fungal decay and attacks by wood-destroying insects. This can extend its service life when it is used in an appropriate environment and installed in accordance with good building practice.
Pressure treatment does not make the timber completely waterproof or maintenance-free. The wood may still absorb and release moisture, leading to natural movement, shrinkage, weathering, colour changes and surface checking.
Cutting, drilling or notching the timber can expose internal wood that has not received the same level of treatment. Apply a suitable end-grain preservative to all newly exposed areas during installation.
Common uses for 7×2 treated timber
The 47 x 175mm section is suitable for a broad range of outdoor and general building projects, subject to its strength grade and the design requirements.
Possible applications include:
- Outdoor timber frameworks
- Garden buildings and structures
- Landscaping projects
- Timber supports and bearers
- Agricultural and equestrian construction
- Raised garden features
- External carpentry and joinery
- General building work
- Bespoke garden structures
- Repairs to existing timber frameworks
- Load-bearing members where correctly graded
- Outdoor DIY and renovation projects
Where the timber will carry structural loads, confirm that it has the correct strength classification for the application. 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 confirm the required spans, loads, support spacing, connections and fixing arrangements for structural projects.
Benefits of the 3.6m length
The 3.6-metre length offers a convenient option for medium-sized building and landscaping projects. It is easier to transport, store and manoeuvre than longer timber while still providing enough length for many common applications.
It can also be cut into multiple shorter sections. Preparing a cutting schedule before beginning work can help reduce offcuts and make efficient use of each length.
The timber’s weight will vary depending on its moisture content. Appropriate lifting and handling procedures should still be followed, particularly when moving several lengths together.
Natural timber characteristics
Timber is a natural product, meaning individual lengths will differ in grain, colour, knots and surface texture. These variations are expected and contribute to the natural appearance of the material.
Knots, resin pockets, minor splits and surface checking may be visible. These features are not automatically defects, although their suitability will depend on the intended application and any relevant grading requirements.
Pressure treatment introduces moisture into the wood. As the timber dries, some shrinkage, twisting, cupping or bowing may occur. Appropriate storage and installation can help manage this natural movement.
Treated timber may initially have a green or brown appearance depending on the preservative system used. The colour will generally soften and weather gradually following exposure to outdoor conditions.
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 7×2 is an approximate imperial description rather than a guarantee of exact finished dimensions. If precise measurements are critical, check the timber before installation or contact us to confirm the current stock specification.
Allowing the timber to acclimatise appropriately can be beneficial where the project requires precise joints or close-fitting components.
Cutting and installation
Use suitable woodworking equipment 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.
Carry out cutting work in a well-ventilated location and avoid breathing timber dust. Collect sawdust and offcuts for responsible disposal. Pressure-treated timber should not be burned on domestic fires, in wood-burning appliances or on garden bonfires.
Apply a compatible end-grain preservative to all cut ends, drilled holes and notches. Use corrosion-resistant fixings suitable for pressure-treated timber, especially in external or moisture-prone environments.
Where the timber forms part of a load-bearing structure, all supports, fixings and connections should follow the approved design and be appropriate for the expected loads.
Storage and maintenance
Store the timber flat, raised away from the ground and supported at suitable intervals. Protect it from prolonged saturation while providing sufficient ventilation around the lengths.
For visible external applications, a compatible wood stain, oil or protective coating may be applied once the timber has dried sufficiently. Follow the coating manufacturer’s recommendations regarding preparation and moisture content.
Inspect outdoor timber periodically, paying particular attention to cut ends, joints, fixing points and horizontal surfaces where water could collect.
Key benefits
- Substantial 47 x 175mm timber section
- Commonly known as 7×2 timber
- Convenient 3.6m length
- 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
- Easier to handle than longer timber lengths
- More durable than untreated softwood
- Suitable for professional and DIY construction
Tanalised Treated Timber 47 x 175mm 3.6m – 7×2 Timber provides a substantial yet manageable section for outdoor construction, landscaping and general building projects. Always confirm its exact dimensions, treatment level and strength grade against the requirements of the intended application before installation.
