7x2 Timber Treated C24
(11 Products)47mm x 175mm treated timber is a heavy-duty structural material engineered to support significant spans and loads in residential and commercial construction. Pressure-treated to ensure long-term resistance against biological decay, these 7x2 sections are a primary choice for high-specification framing, floor joists, and roofing rafters.
Understanding 7x2 Treated Timber
47mm x 175mm sawn treated timber, frequently identified by its nominal 7x2 inch measurement, is a high-performance carcassing product designed for demanding structural roles. These lengths are kiln-dried to improve dimensional stability and strength-graded to C24 standards, ensuring they provide the mechanical stiffness required for longer spans. The timber undergoes a rigorous pressure-treatment process where preservatives are forced deep into the wood fibres, creating a durable barrier against fungal rot and wood-boring insects.
The timber is regularised to a finished size of approximately 45mm x 170mm. This precision finishing includes eased edges, which facilitates easier manual handling and ensures a consistent height across floor or roof planes. The 175mm depth offers superior resistance to deflection, making it an essential component for structural floor systems that must support heavy dead and imposed loads.
Available in a range of lengths from 3m to 7.2m, this inventory allows for efficient material specification across diverse project scales. Whether supplied as individual lengths for bespoke builds or in 66-length bulk packs for volume construction, these materials provide a reliable and durable structural framework.
Material Range
- Individual 47mm x 175mm Lengths: Single units of pressure-treated structural timber available in lengths of 3m, 3.6m, 4.2m, 4.8m, 6m, and 7.2m to suit various span requirements.
- Bulk 7x2 Timber Packs: Large-scale 66-length packs designed for trade efficiency and high-volume installations (available for all lengths excluding 7.2m).
Performance Benefits
- High-Level Preservation: Pressure-treated with advanced biocides to prevent rot, decay, and insect attack in both internal and external environments.
- Superior Strength Grading: Provided in a C24 grade to offer higher load-bearing capacities and greater structural reliability than standard domestic timber.
- Dimensional Stability: Kiln-dried to reduce moisture content, minimising the risk of the timber warping or twisting after installation.
- Eased Edges: Regularised for uniform dimensions and rounded at the corners for improved site safety and handling.
Typical Applications
- Primary Floor Joists: Creating stable and high-load-bearing horizontal floor structures.
- Roof Rafters and Purlins: Forming the main sloping or horizontal supports in large-scale roof frameworks.
- Heavy-Duty Studwork: Constructing load-bearing internal partitions and external wall frames.
- Decking Substructures: Providing a robust, treated base for elevated or ground-level external platforms.
- Flat Roof Frameworks: Supporting the deck and insulation layers in flat roof construction.
Specification & Standards
- BS EN 14081-1: Strength graded structural timber with rectangular cross section.
- BS EN 335: Durability of wood and wood-based products - Use classes.
- BS EN 599-1: Performance of preventive wood preservatives as determined by biological tests.
Related Materials and Construction Uses
These 47mm x 175mm sections are often utilised as the primary support system within a building's skeleton. For projects where engineering specifications require maximum rigidity and a high-strength-to-weight ratio, these lengths are selected from our premium C24 structural wood inventory. They are frequently used alongside structural timber for joists to create complete, code-compliant flooring and roofing assemblies.
To ensure the longevity of the installation, all site-cut ends should be retreated with an end-grain preservative. These timber lengths integrate seamlessly with standard metalwork connectors, vapour control layers, and breathable membranes to form a high-performance building envelope.
Frequently Asked 7x2 Questions
Can I Paint 7x2 Timber C24?
It’s certainly possible to paint treated timber but an important thing to remember is that treated timber should not be painted immediately after it has been purchased.
When shipped, most 7 x 2 C24 timber is still “wet” and time is needed for the chemicals to settle and dry.
In terms of time, it can be up to a few weeks before it is dry and ready to be used. This is largely dependent on where the wood is being stored.
If there is too much heat or direct sunlight, this can cause the timber to warp rather than dry out. Conversely, damp conditions can lengthen the drying out period, prolonging the time before work can begin.
Is It Easy To Cut C24 Graded 7x2 Timber To My Preferred Size?
7x2 treated wood can be readily cut to your desired length, however, this should only be done with the right equipment, eye protection, and a respirator since the cutting process releases tiny airborne particles of wood, possibly impregnated with the chemicals used in pressure-treating.
Treated wood also cuts a little more like wet wood so some extra care should be afforded to ensure the blade doesn’t slip while cutting.
What's The Difference Between 7x2 Treated Timber & 7x2 Sawn Timber?
Sawn timber is wood that has been cut to the required dimensions but hasn't yet been pressure treated and kiln dried.
Pressure-treated timber, otherwise known as tanalised timber (due to the Tanalith E wood preservative that impregnates the wood) provides many benefits, such as resistance to the elements.
The goal of pressure treating wood is to force preservative chemicals deep into the timber's cellular structure. This pressure treatment process will often include copper and organic co-biocides, which help to repel both insects and moisture.
Please note: timber is a natural product that may vary in colour, visual details, knots, grain, and texture.
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