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C16 Treated Timber Joists

At Armstrong Supplies, we understand the importance of having access to the right materials that are fit for purpose and that’s why we offer the very best in C16 kiln-dried timber treated joists. All construction jobs require the latest materials and that’s why we make sure that we offer the best quality C16 graded carcassing timber.


When it comes to floor joists, roof joists, or rafters, we understand that our customers are looking for value for money and that’s what we offer. With our C16 carcassing timber, you will benefit from exceptional properties but also a level of cost-effectiveness that makes it the preferred choice over C24 timber.

What is C16 Treated Timber?

We can say that timber is treated when it has been pressurized with a preservative that inhibits attack and fungal decay. This treated timber is strength graded based on the British Standard in the BS 5268. C16 refers to the strength grade of the treated timber. It is kiln dried and is used on internal floor joists, roof joists, roof rafters, timber framing, and the like.

What is the difference between C16 and C24 timber?

Timber can be strength graded to C16 or C24 and is equivalent to BS EN 14081 and BSEN19:1995 respectively. Although the former is strong enough for some applications, C24 treated timber is stronger.

Can I use C16 for decking?

Yes. Whether you are looking for treated decking joists or rafters, our C16 kiln dried timbers are specifically designed so they are fit for purpose. They go through rigorous stress grading and that provides peace of mind knowing that they have the ability to withstand the required loads that will be applied to them. This makes them perfect for use as joist and rafters.

They come in a wide range of lengths, widths and thicknesses too, ensuring you can find timber that fits the needs of your project. So whether you are installing rafters or floor joists then you can put your trust in our range of projects.

What’s more, they are all treated and that ensures that they come with an added level of durability in those applications where they might be exposed to moisture. Therefore, they are ideal for use as a decking timber framing in areas where there is some moisture while not being in direct contact with the ground.

All of the timber we provide is regularised which means that they come with consistent dimensions which makes them simple to work with and use. What’s more, they are also planed all around and come with eased corners, ensuring they are comfortable when handled.

Can I use C16 timber outside?

Yes. If you’re looking for longevity then our C16 carcassing timber will tick every box since it is at low risk of an insect attack. When they are used above DPC, they have a 15-year life span and they adhere to approved trade practice, ensuring they deliver exceptional structural performance.

From repair jobs to construction projects and DIY jobs, we offer a wide selection of C16 timbers from manufacturers that are widely recognized, ensuring you benefit from cost savings and quality that will last for many years.

At Armstrong Supplies, we appreciate how vital the right materials are to any project. From safety to durability, we make sure that we only source products that fit our high standards. What this means is that our customers can rely on our wide range of C16 timbers, all of which are guaranteed to provide an effective solution, regardless of the project you are undertaking.

Click to read more on Grading and Treatment of Timber