What is Pre-Treated Wood?

You’ve invested in some wood products because they’re the durable and sustainable choice, right? That’s definitely the case if they are pre-treated wood. Pre-treatment makes the wood last longer and it’s a sustainable option. Here’s why.

Pre-treated wood is wood that’s treated with preservative chemicals. This helps to make the wood last longer and protects it from:

• Structural degradation like rotting
• Decay due to fungi
• Destruction by insects like termites
• Flames

Pre-treating wood protects the less durable parts of a tree that are often scrapped or don’t last long. This makes the most of our precious timber resources and minimises waste.

Why treat wood?

All trees have an inner core known as heartwood. The outer layer is younger material called sapwood. The sapwood is where the nutrients are. However, it’s the heartwood that contains everything that protects the tree from insects and decay.

The sapwood is a source of nutrients, so it’s an attractive meal for insects and other organisms. This can mean that sapwood is often discarded or doesn’t tend to last that long. However, pre-treatment is a game changer.  

The benefits of pre-treated wood

Pre-treated wood lasts longer than untreated wood. This means there’s less of a need to cut down trees in the long run. Using untreated wood is a false economy. It might only last 5 years whereas pre-treated wood could last 25 years. That’s a lot of trees saved.

Depending on the conditions, untreated wood can start to rot within just a couple of years. And even worse, it can only take a few weeks for termites and other organisms to affect their integrity.

Untreated wood will burn quicker than pre-treated wood when it’s exposed to flames.

How is wood treated?

​Pressure treatment

Pressure treatment impregnates the wood fibres with chemical preservatives. This targets the fibres just under the surface. The type of treatment used will depend on what the end use is. 

Topical treatment

Topical treatments are applied to the surface of the wood. Treatments are usually sprayed or brushed on, or the wood is dipped in the preservative.

Pre-treated wood: How is treatment decided upon?

When deciding on which preservative treatment to use, a few things matter:

The species of wood

Some types are less durable than others and don’t take to treatment as well.

The end use 

Will it be fence posts, used in construction, or something else? This will determine exactly how durable it needs to be.

How you expect the wood to last

How long do you expect the wood to last before it needs replacing? If you want it to last 60 years, it’s probably going to need heavy-duty treatment.

There are minimum standards for pre-treated wood which are set out in British Standard BS 8417 (2014). The point of these standards is to protect the customer by making sure the timber is fit for its purpose.

What do we treat our bin stores with?

What we treat our bin stores with depends on whether you have chosen a painted bin store or natural. If you have chosen painted then we use a clear half water-based treatment. This does not blast the treatment as far into the wood which is not necessary given it will get two coats of Osmo paint. If you choose a non-painted store then we use a green treatment as this offers the strongest and longest protection.

So choosing pre-treated wood is the common sense choice and a sustainable one. It’s better for the environment. It lasts longer too, and at the end of its life, it can easily be re-used or recycled. Peace of mind for you and protection for the planet. You can’t argue with that.

For more interesting articles on all things timber, check out the rest of our blog.