Tanalised Treated Timber 47 x 125mm 3.6m – 5×2 Timber
Tanalised Treated Timber 47 x 125mm 3.6m is a versatile pressure-treated softwood section suitable for outdoor construction, landscaping and general building projects. It is commonly referred to as 5×2 timber, based on its traditional approximate imperial dimensions of 5 inches by 2 inches.
The 125mm depth provides a useful middle size between common 4×2 and 6×2 timber. This makes it suitable for projects requiring a more substantial section than 4×2 without the additional depth and weight of larger alternatives.
Its practical 3.6-metre length is suitable for many garden, building and landscaping applications. It can be installed as a complete length or cut into smaller sections to meet the requirements of the project.
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 when compared with untreated softwood used in similar environments.
Product dimensions
The nominal product dimensions are:
- Metric section: 47mm x 125mm
- Common imperial name: 5×2 timber
- Length: 3.6m
- Material: Treated softwood
- Treatment: Pressure treated or tanalised
- Suitable for: Building, landscaping and outdoor projects
The name 5×2 is a traditional trade description rather than an exact imperial conversion. Use the stated metric dimensions when measuring, planning and cutting the timber.
What is tanalised timber?
Tanalised timber is softwood that has been treated with wood preservative through a controlled vacuum and pressure process. This encourages the preservative to penetrate deeper into the material than a basic surface-applied coating.
The treatment helps protect the wood against fungal decay and attacks from wood-destroying insects. It can extend the service life of the timber when it is correctly specified, installed and maintained in suitable external conditions.
Pressure treatment does not make the timber completely waterproof or maintenance-free. The wood can still absorb and release moisture, which may lead to natural movement, shrinkage, weathering, surface checking and colour changes.
Cutting, drilling or notching 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 5×2 treated timber
The 47 x 125mm section is suitable for a broad variety of outdoor and general construction work. Its suitability will depend on the product’s strength grade, treatment level and the design requirements.
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 building work
- Bespoke outdoor structures
- Repairs to existing timber frameworks
- Load-bearing members where correctly graded
Where the timber is intended to 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, load, support spacing, connections and fixing arrangement should be determined by a suitably competent person where structural performance is necessary.
Benefits of pressure-treated timber
Untreated softwood may be vulnerable to decay when exposed to damp or outdoor conditions. Pressure treatment helps protect the wood from common biological causes of deterioration.
The benefits include:
- Additional protection against fungal decay
- Protection against wood-destroying insects
- Greater durability than untreated softwood
- Suitable for many external applications
- Useful for garden and landscaping projects
- Can be cut and worked using suitable tools
- Suitable for professional building work
- Practical for home improvement and DIY projects
The correct treatment or use class must still be selected for the intended location. Timber installed in direct ground contact or areas of persistent moisture may require a particular treatment specification.
Natural characteristics of softwood
Timber is a natural product, so individual lengths will vary in grain, colour, knots and surface texture. These differences are normal and form part of the material’s natural appearance.
Knots, resin pockets, minor splits and surface checking may be present. These features do not automatically indicate a defect, although their acceptability will depend on the intended application and any relevant grading requirements.
Pressure treatment introduces moisture into the timber. As the wood dries, some natural shrinkage, twisting, cupping or bowing may occur. Correct storage and installation can help manage this movement.
Newly treated timber may initially have a green or brown appearance depending on the preservative system used. The colour will generally 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 5×2 is an approximate imperial description rather than a guarantee of exact finished measurements. If precise dimensions are essential, check the timber before installation or contact us to confirm the specification of the available stock.
Allowing the timber to acclimatise appropriately can be useful where the project requires accurate joints or close-fitting sections.
Cutting and installation
Use suitable woodworking equipment fitted with sharp blades when cutting or drilling this timber. Wear protective gloves, eye protection and appropriate respiratory protection while handling, sawing or sanding treated wood.
Work in a well-ventilated location and avoid breathing timber dust. Collect sawdust and offcuts for responsible disposal. 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 should 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 air to circulate around each length.
A compatible wood oil, stain or protective coating may be applied to visible outdoor timber once it has dried sufficiently. Follow the coating manufacturer’s instructions for preparation and moisture content.
Inspect external timber periodically, paying particular attention to cut ends, joints, fixing points and areas where water may collect.
Key benefits
- Versatile 47 x 125mm timber section
- Commonly known as 5×2 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 for different project requirements
- More durable than untreated softwood
- Suitable for professional and DIY construction
- Practical intermediate size between 4×2 and 6×2
Tanalised Treated Timber 47 x 125mm 3.6m – 5×2 Timber is a practical choice 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.
