What is H5 treated pine and what is it used for?

Is H5 treated pine right for your next project?

H5 pine is one of the most highly rated types of timber in terms of protection against different types of exposure.

Want to know more about H5 treated pine?

The following blog post covers everything you need to know.

What is H5 pine?

H5 treated pine is one of the highest durability levels of pine treatment.

This means it’s designed to stand up against severe conditions, like in-ground applications or even contact with fresh water.

H5 timber is treated for protection against very severe decay as well as borers and termites.

Uses for H5 treated pine

You can use H5 treated pine for a wide range of purposes including:

  • Retaining walls. H5 treated pine will ensure retaining walls are long-lasting and protected from constant contact with soil and moisture.
  • House stumps. H5-treated pine ensures your home’s foundation is well supported and rot-resistant, although concrete stumps are a more popular choice these days.
  • Piling. H5 treated pine is an ideal choice for piling structures.

How long will H5 treated pine last in the ground?

Because H5 treated pine is highly resistant to rot and decay, you can expect it to last for decades—even up to 100 years in some cases—when used in the ground.

RELATED: What is ACQ treated pine?

Differences between H2 and H5 treated pine

The difference between H2 and H5 treated pine is that H5 offers a lot more protection against exposure.

H2 treated pine can be used for interior, above-ground use only and is resistant to termites but shouldn’t be used for applications where it may get wet or be in contact with the ground (for example, cladding or decking).

H5 treated pine can be used in-ground and outside, and in contact with fresh water. It’s suitable for applications such as posts, sleepers and poles.

What is the difference between H5 and H6 treated pine?

The difference between H5 and H6 treated pine is that H5 is suitable for use in-ground contact, while H6 is suitable for in-ground contact as well as fresh water contact.

As an example, fence posts need to be at least H5 graded to withstand rot from being in the ground, or else they will deteriorate quickly.

You can also use H5 grade timber for garden beds or other projects that involve direct contact with soil.

On the other hand, if your project involves building something that will touch fresh water—perhaps you’re constructing a boat dock—then it needs to be built out of timber graded as H6.

So, when choosing the right timber for your project, think about whether your structure will come into contact with soil (H5) or freshwater (H6) since they are treated differently.

What does F5 mean in timber?

F5 is a structural classification that describes the strength of framing timber.

If you’re using timber for structural use (i.e. supporting, say, your roof), it’s important to make sure the timber is structurally-rated. That’s why there’s an F rating system for timber.

The higher the F number, the stronger the timber. F7, for example, is stronger than F5.

F7 is considered the minimum requirement for building.


What does H stand for in treated pine?

“H” stands for hazard class. An H1-H6 hazard rating system determines the level of treatment.
The higher the rating, the higher the level of treatment. In other words, H1 is the lowest hazard class (and requires the lowest level of treatment) and H6 is the highest hazard class (and requires the highest level of treatment).
The lowest levels are protected only against minor insect attacks while the top levels are protected against rot when placed in soil or water.