Which timber is best for decking?

When picking your decking timber, you need to think about the durability, price and maintenance. Depending on these three factors, you will be able to choose your perfect decking timber. The top 5 Australian timber decking choices are (not necessarily in that order):

1. Spotted gum
2. Ironbark
3. Merbau
4. Blackbutt
5. Treated pine

There are many more, like Karri, Jarrah, Tallowwood and many more, but these 5 are among the most usual picks. They have different colours and qualities, so it is all up to you. Your final choice should be based on the characteristics of your timber, its colour and texture, durability and strength.

While you can make a choice quote easily just by looking at the wood, it will be much more difficult for you to determine whether the wood can sustain weather conditions, how often you have to resurface your decking and much more.

That is why it is a wise idea to get some help from the decking professionals who will give their opinion based on the circumstances in which you are building your decking.

How Is Decking Timber Rated?

There are several important ratings you should be aware of when you want to choose the best timber for your decking. These ratings are:

• Durability classes
• Hazard levels
• Stress Grading

What Is the Durability of Timber?

The natural durability of timber classifies all timber into four groups. These groups are based on the timber resilience toward decay in the ground and above ground, as well as to termites. However, this classification classifies the timber only according to its heartwood.

The sapwood is always the class 4, which is the lowest and the least resilient class of timber. This type of timber durability is taken into consideration when the timber decking life expectancy is measured.

Class 1 – The most durable decking timber is Class 1, and it can be expected to last for 40 years above ground and 25 in ground. Class 1 is the highest durability. Spotted gum and ironbark are examples of timber from this class.

Class 2 – This is also durable timber, although its life expectancy is not as high as the class 1 decking timber. The minimal life expectancy for both in-ground and above-ground timber is 15 years. The maximum above-ground life expectancy reaches 40 years, while the in-ground – 25. Blackbutt belongs to this group, although sometimes, it is classified as Class 1.

Class 3 – This is as low as you should go with your decking timber. This timber is expected to live a maximum of 15 years both on the ground and above ground. The minimum is 5 for in-ground and seven for above-ground. White stringybark belongs here.

Class 4 – This includes all the sapwood. You can expect this type of timber to last up to 5 years in the ground and up to 7 years above ground.

What Is Timber Hazard Level System?

Hazard level marking goes from H1 to H6. This marking signifies the level of hazard to which the decking timber is treated. Hazards include termites, borers, fungi, weather and decay to some degree. For your decking purposes, use H3-treated timber as the lowest hazard level rating. Here is what the markings mean:

H1 – Timber is protected from insects but not termites and some borers. Used mostly for furniture.
H2 – Timber is protected from insects and termites but is not suitable for outdoor and in-ground use.
H3 – Timber protected from borers, termites and some decay. Used outside for above-ground projects.
H4 – Timber is protected from termites, borers, and severe decay. Used outside and inground.
H5 – Timber protected from termites, borers, and severe decay and can be used in contact with fresh water.
H6 – Timber protected from Marine borers and decay. Used for boats and other marine uses.

What is the Difference Between H3 and H4 Treated Pine?

The main difference is that you will not be able to use H3-treated pine for in-ground projects. You are safe and sound when it comes to timber decking with both H3 and H4-treated pine decking, but if you have the choice, use the H4 since it is more resilient and your timber is protected from severe decay.

What Is Stress Grading for Timber?

This grading can be done both visually and mechanically. The idea is to evaluate the density, imperfections, size, length and overall endurance of the timber. Visually, gradings go from F1 to F27. Treated pine decking is F5 to F7, for example. Mechanical marking for timber is MGP.

Which Decking Timber Should You Choose?

Let’s get back to the beginning and apply what we have discussed here about timber durability and resilience. If you want the strongest and the most durable wood, you should go for ironbark. This is Class 1 hardwood that has excellent resilience. However, it will not be the cheapest option out there.

Another very interesting option is the treated pine. Treated pine is not hardwood by itself. Untreated, pine is quite fragile and prone to decay. However, with all the excellent treatments, you get the decking timber, which is as durable as hardwood, but you can choose from a variety of hues, and it is not as expensive or heavy.

It is also easier to install, but that is not something that you should be worrying about because you will leave that to the professionals. The average cost of building decking is around $320 per square metre if you don’t include the roof. However, this price may vary greatly. It all depends on the wood you choose and the project you have.

It is difficult to give this kind of estimate without seeing the actual terrain and knowing the price of the decking timber you choose. However, if you have these details, the best you can do is collect several quotes for the same project and get more information about the ballpark in which your project is.

Get accurate quotes for your timber decking project from real Australian decking experts. Once you have all the prices and the quotes listed, you will easily make your decision. Not sure about treated pine or ironbark? Ask the experts. They will send you quotes for both options and give you something to work with.