4x3 Treated Timber C24 Regularised Sawn 75x100mm

Our 4x3 C24 pressure treated timber is available in two lengths: 3.6m and 4.8m. They are sized at 75x100mm, but as they are regularised for a smooth finish and even sizing, the finished size is closer to approx 73x95mm. Made from high quality, responsibly sourced timber from FSC certified forests, each of our 4x2 timber is kiln dried for additional strength and durability, and is pressure treated for resistance to rot and pests. 

• FSC Certified Timber
• For use in exterior and structural applications
• Regularised for uniform size, with eased corners
• Graded to C24 strength grade
• Treated to UC2

What is 4x3 Timber in mm?

Traditionally measured in inches, “4x3” refers to the size of the joist in inches. If you want to know what 4x3 Timber is in mm - the equivalent size is 75 x 100mm. However, as the timber is regularised, this means that to achieve a timber joist that is uniform in size the entire way along the length, the “finished” size can be a few mm smaller than 75x100mm, usually closer to 73mm x 100mm.

The size difference is minimal and in the vast majority of projects will make no difference to your project, and is standard across 75x100, 4x3 regularised timber joists.

What is 4x3 C24 Timber Used For?

Our 4x3 treated timber is graded C24 and is typically used for structural framing applications but can also be used in roofing, floors and other structural projects. Our 4x3 timber can also be used in building decking framing due to it’s superior strength, though it will need further treatment to protect against moisture and pest. 

What is Regularised Timber?

Throughout our website, you will see many timber joists referred to as “regularised” - this means that the length of timber has been machine-finished to achieve a smooth finish and a uniform length and width along the length of the timber joist. This can impact the finished size of the product by a few millimetres. The most common types of regularised timber joists are C16 and C24.

What Does Kiln Dried Mean?

Kiln dried timber is made through the process of kiln drying - where cut timber boards are dried in kilns with continuous, even application to remove excess moisture from the fresh timber. This reduces the weight, increases the strength and straightness, and makes it easier to work with. It is also a much faster process than air-drying timber joists, which can take several months to a year. 

What Lengths Do 4x3 C24 Timber Joists Come in?

Our pressure treated 4x3 regularised timber joists are available in both a 3.6m and 4.8m length. We do our best to keep these sizes available for delivery, but occasionally, you may receive a longer length as a substitute if stock is delayed or unavailable in your area. 

What Does C24 Stand For?

Regularised timber is commonly graded into one of two grades in the UK - C16 or C24. The “C” refers to the variety of wood used, which in this case is Conifer. The number refers to the strength grading that timbers are sorted into based on a number of factors such as imperfections, knots, etc, with C24 being the stronger of the two.

Most commonly, C16 timber joists are used in many wall and roofing applications, whilst the C24 is used for particularly high-strength requirements such as roofing and flooring joists.