01163 032668
01163 032668
Treated Timber
C16 Treated Timber & Joist Timber
Our treated timber range includes C16 graded timber in a choice of common sizes and lengths, from compact 2x2 sections through to larger 8x2 timber. These treated timber sections are suitable for a wide range of building, framing, landscaping and outdoor construction projects.
C16 Treated Timber 8x2 (45x195mm Finished Size)
Arranwood
Original price
£5.00
-
Original price
£20.00
Original price
£5.00
-
£20.00
£5.00
-
£20.00
Current price
£5.00
In stock
C16 treated timber in 8x2 nominal size, supplied at 47x200mm and regularised to a finished size of approximately 45x195mm. Available in 1m, 1.2m, 1...
View full details
Original price
£5.00
-
Original price
£20.00
Original price
£5.00
-
£20.00
£5.00
-
£20.00
Current price
£5.00
C16 Treated Timber 7x2 (45x170mm Finished Size)
Arranwood
Original price
£5.00
-
Original price
£20.00
Original price
£5.00
-
£20.00
£5.00
-
£20.00
Current price
£5.00
In stock
C16 treated timber in 7x2 nominal size, supplied at 47x175mm and regularised to a finished size of approximately 45x170mm. Available in 1m, 1.2m, 1...
View full details
Original price
£5.00
-
Original price
£20.00
Original price
£5.00
-
£20.00
£5.00
-
£20.00
Current price
£5.00
C16 Treated Timber 6x2 (45x145mm Finished Size)
Arranwood
Original price
£4.00
-
Original price
£16.00
Original price
£4.00
-
£16.00
£4.00
-
£16.00
Current price
£4.00
In stock
C16 treated timber in 6x2 nominal size, supplied at 47x150mm and regularised to a finished size of approximately 45x145mm. Available in 1m, 1.2m, 1...
View full details
Original price
£4.00
-
Original price
£16.00
Original price
£4.00
-
£16.00
£4.00
-
£16.00
Current price
£4.00
C16 Treated Timber 5x2 (45x120mm Finished Size)
Arranwood
Original price
£4.50
-
Original price
£15.50
Original price
£4.50
-
£15.50
£4.50
-
£15.50
Current price
£4.50
In stock
C16 treated timber in 5x2 nominal size, supplied at 47x125mm and regularised to a finished size of approximately 45x120mm. Available in 1m, 1.2m, 1...
View full details
Original price
£4.50
-
Original price
£15.50
Original price
£4.50
-
£15.50
£4.50
-
£15.50
Current price
£4.50
C16 Treated Timber 4x2 (45x95mm Finished Size)
Arranwood
Original price
£3.50
-
Original price
£11.00
Original price
£3.50
-
£11.00
£3.50
-
£11.00
Current price
£3.50
In stock
C16 treated timber in 4x2 nominal size, supplied at 47x100mm and regularised to a finished size of approximately 45x95mm. Available in 1m, 1.2m, 1....
View full details
Original price
£3.50
-
Original price
£11.00
Original price
£3.50
-
£11.00
£3.50
-
£11.00
Current price
£3.50
C16 Treated Timber 3x2 (45x70mm Finished Size)
Arranwood
Original price
£2.50
-
Original price
£8.00
Original price
£2.50
-
£8.00
£2.50
-
£8.00
Current price
£2.50
In stock
C16 treated timber in 3x2 nominal size, supplied at 47x75mm and regularised to a finished size of approximately 45x70mm. Available in 1m, 1.2m, 1.8...
View full details
Original price
£2.50
-
Original price
£8.00
Original price
£2.50
-
£8.00
£2.50
-
£8.00
Current price
£2.50
C16 Treated Timber 2x2 (45x47mm Finished Size)
Arranwood
Original price
£2.00
-
Original price
£6.00
Original price
£2.00
-
£6.00
£2.00
-
£6.00
Current price
£2.00
In stock
C16 treated timber in 2x2 nominal size, supplied at 47x50mm and regularised to a finished size of approximately 45x47mm. Available in 1m, 1.2m, 1.8...
View full details
Original price
£2.00
-
Original price
£6.00
Original price
£2.00
-
£6.00
£2.00
-
£6.00
Current price
£2.00
Looking for joist timber? Our larger C16 treated sections are available in common joist sizes including 4x2, 5x2, 6x2, 7x2 and 8x2, making it easier to choose the timber section suited to your project.
All dimensions are shown using the traditional nominal timber sizes alongside the approximate finished size, so you can choose the right C16 treated timber for your application.
C16
Strength graded timber
2x2–8x2
Common timber sections
Multiple
Lengths available
Treated
For added durability
Which Treated Timber Size Do I Need?
Select a nominal timber size below to see its approximate finished dimensions and common applications.
Select a timber size:
C16 Treated Timber Sizes
Choosing timber by its traditional imperial size can be confusing because the nominal dimensions are not always the same as the finished dimensions. The C16 treated timber in this range is supplied in larger nominal sections and regularised to a consistent finished size.
| Nominal size | Approx. finished size | Common applications |
|---|---|---|
| 2x2 | 45x47mm | Framing, supports, battens and smaller construction work |
| 3x2 | 45x70mm | Framing, supports and general construction |
| 4x2 | 45x95mm | Joists, decking subframes, framing and general construction |
| 5x2 | 45x120mm | Larger framing, joists and outdoor structures |
| 6x2 | 45x145mm | Joists, flooring structures, decking and structural framing |
| 7x2 | 45x170mm | Larger joists and structural timber applications |
| 8x2 | 45x195mm | Larger joists, structural framing and substantial timber structures |
Treated Joist Timber
Joist timber forms the framework that supports floors, decks and other structures. Where treated timber is required, C16 treated timber is commonly used for suitable structural and outdoor applications where the timber specification, spans, loading and support arrangement are appropriate.
Common treated joist sizes include 4x2, 5x2 and 6x2, while the larger 7x2 and 8x2 sections can be used where a larger timber section is required. The correct joist size should always be determined by the span, spacing, loading and structural design rather than simply choosing the largest available section.
Important when choosing joist timber
Timber size alone does not determine whether a joist is suitable. Floor span, joist spacing, loading, support conditions and the grade of timber all affect the required section. For structural floors and other load-bearing applications, use appropriate span tables or obtain professional structural advice.
What Is C16 Treated Timber?
C16 is a strength classification for structural softwood timber. The C16 grade tells you about the mechanical properties of the timber; the treatment is a separate characteristic that provides protection against biological deterioration.
This means C16 treated timber should not be confused with untreated C16 timber. The timber can be strength graded as C16 while also being treated for applications where additional protection is required.
C16 treated timber is widely used for suitable construction applications including framing, decking subframes, joists, garden structures and other projects where a graded treated softwood is specified.
C16 vs Treated Timber: They Mean Different Things
This is an important distinction when buying timber.
C16 describes the strength grade.
Treated describes the preservative treatment applied to the timber.
Therefore, when you search for C16 treated timber, you are looking for timber that combines a C16 strength classification with treatment appropriate to its intended application.
What Is Treated Timber Used For?
Joists & Floor Structures
Larger C16 treated timber sections can be used for suitable joist and floor construction where the timber size and treatment meet the project requirements.
Decking Subframes
Treated timber is commonly used to create the supporting framework beneath decking boards. The appropriate section depends on span, spacing and the construction design.
Garden Structures
C16 treated timber can be suitable for many outdoor structures including framing, pergolas and other timber construction where the specification is appropriate.
Building Frames
Smaller and medium treated sections can be useful for framing, supports and general construction projects.
Structural Timber
C16 graded timber is a structural strength class. Always select the correct section based on the design requirements rather than choosing by appearance alone.
Outdoor Timber Projects
Treated timber is suitable for many outdoor projects where protection against biological deterioration is required and the treatment specification is appropriate.
4x2 Treated Timber
4x2 treated timber is one of the most commonly searched timber sizes. The C16 treated 4x2 in this range is supplied at approximately 45x95mm finished size and is available in multiple lengths.
4x2 treated timber is commonly considered for joists, decking subframes, framing, garden structures and general construction, subject to the requirements of the individual project.
6x2 Treated Timber
6x2 treated timber provides a deeper timber section than 4x2, with an approximate finished size of 45x145mm. It is commonly used where a larger joist or framing section is required.
The additional depth can make 6x2 timber suitable for applications where a 4x2 section would not provide the required span or capacity. Always use the appropriate structural calculations or span guidance for load-bearing applications.
8x2 Treated Timber
8x2 treated timber is one of the largest sections in this range, with an approximate finished size of 45x195mm. It is suited to projects requiring a deeper timber section, including larger joist and structural framing applications where specified.
Nominal Timber Size vs Finished Timber Size
Timber is often ordered using traditional sizes such as 4x2, 6x2 or 8x2. These are nominal dimensions and should not be assumed to be the exact dimensions of the timber you receive.
For example, the C16 treated 4x2 timber in this range has a nominal size of 47x100mm and an approximate finished size of 45x95mm. The 6x2 is supplied at approximately 47x150mm and finished at around 45x145mm, while the 8x2 is approximately 47x200mm before regularisation and around 45x195mm finished.
If you are designing around existing timber, hangers, brackets or other components, use the stated finished dimensions rather than relying only on the nominal size.
How to Choose the Right Treated Timber
1. Choose the grade
Check whether your project specifies C16, C24 or another timber grade.
2. Choose the section
Select the required width and depth. For joists, the correct size depends on span, spacing and loading.
3. Choose the length
Choose a length that suits your project while allowing for cutting, joints and installation.
Why Buy Treated Timber?
Untreated timber is not automatically suitable for every environment. Where timber is exposed to conditions that increase the risk of decay or biological attack, an appropriate preservative treatment can provide additional protection.
The correct treatment depends on where and how the timber will be used. Always check the treatment specification against the intended application, particularly for timber that will be exposed to weather or ground conditions.
Treated Timber FAQs
What is C16 treated timber?
C16 treated timber is softwood that has been strength graded to C16 and treated with a preservative. C16 describes the structural strength class, while treated describes the timber's preservative treatment.
Can C16 treated timber be used as joists?
C16 timber can be used for suitable joist applications where the required grade, section, span, spacing and loading are appropriate. The correct joist size should be established using the relevant span and structural requirements rather than selecting a section by size alone.
What size is 4x2 treated timber?
The nominal size is 47x100mm, while the treated 4x2 timber in this range is regularised to approximately 45x95mm finished size.
What size is 6x2 treated timber?
The nominal size is approximately 47x150mm and the finished size is approximately 45x145mm.
What size is 8x2 treated timber?
The nominal size is approximately 47x200mm and the finished size is approximately 45x195mm.
What is the difference between C16 and C24 timber?
C16 and C24 are different strength classes for structural timber. C24 has higher specified strength properties than C16. The correct grade depends on the structural requirements of the project.
What is treated joist timber used for?
Treated joist timber can be used for suitable floor structures, decking subframes and other construction applications where treated structural softwood is specified. The required timber section depends on span, spacing and loading.
Is treated timber suitable for decking?
Treated timber is commonly used for decking subframes. The appropriate timber section depends on the design, span, joist spacing and intended loading.
What does 4x2 mean in timber?
4x2 is a traditional nominal timber size. It does not necessarily represent the final dimensions of the timber. The C16 treated 4x2 in this range has an approximate finished size of 45x95mm.
What is regularised timber?
Regularised timber has been processed to provide a more consistent finished cross-section. This makes it easier to work with when accurate dimensions are important.
Can treated timber be used outside?
Treated timber is designed to provide additional protection against biological deterioration, but suitability depends on the treatment specification and the conditions in which the timber will be used. Check the treatment information for the particular product.
What is the largest treated timber size available?
The largest section currently shown in this treated timber range is 8x2 nominal size, with an approximate finished size of 45x195mm.
Need help choosing a timber size?
For structural applications such as floors, roofs and load-bearing joists, the correct timber section should be established from the span, spacing, loading and construction details. If you are unsure, obtain appropriate structural advice before ordering.