What is the difference between H2 & H3 Treated Pine

Which Treated Timber is Right for Your Project?

Treated pine offers durability and resistance against environmental factors that can compromise structural integrity. Builders and trades need to select the right treatment class based on the conditions the timber will be exposed to. This blog compares H2 and H3 treated pine, highlighting their differences, applications, and how to choose the best option for your project.

What is Treated Pine?

Treated pine is a softwood timber infused with preservatives to protect it from decay, insect attacks, and fungal growth. This treatment process increases its longevity and, depending on the treatment type, allows it to be used for external applications.

Understanding H2 Treated Timber

H2 treated pine, also known as blue pine, is designed for interior, above-ground use where it is protected from moisture. It is treated with chemicals which offer protection against termites but do not make the timber resistant to fungal decay.

Common Applications

Blue pine is commonly used for:

• Wall framing in residential and commercial buildings
• Roof frames, trusses and internal beams
• Flooring substrates.

Advantages and Considerations

Advantages:

• Provides effective termite protection
• Affordable compared to higher treatment grades
• Lightweight and easy to work with.

Considerations:

• Not suitable for external applications
• It does not provide resistance to fungal decay or prolonged moisture exposure.

What is H3 Treated Pine?

H3 treated pine is designed for outdoor, above-ground use, where it will be exposed to weather conditions such as rain, humidity, and UV radiation. This treatment process provides resistance to fungal decay, rot, and insects.

Common Applications

H3 treated timber is best suited for:

• Decking subframes
• Fascia boards
• Pergolas and outdoor structures.

Advantages and Considerations

Advantages:

• Resistant to moisture and fungal decay
• Suitable for outdoor and exposed applications
• Increased lifespan compared to untreated or H2 timber.

Considerations:

• More expensive than H2 treated timber
• Should not be used in direct ground contact

 

Key Differences Between H2 and H3 Treated Pine

Feature	H2 Treated Timber	H3 Treated Timber
Treatment Chemicals	Termite-resistant chemicals	Copper-based preservatives for decay & insect resistance
Intended Use	Indoor, above-ground	Outdoor, above-ground
Moisture Resistance	Not moisture-resistant	Resistant to moisture & fungal decay
Durability	Protection against termites only	Protection against termites, fungi & rot

Choosing the Right Treatment for Your Project

Treated pine allows protection against termites, fungi and rot, ensuring your building structure is long-lasting. Bowens supplies a wide range of treated timber including H4 treated pine and H5 treated pine.

To learn more about the timbers you need for your next project, read our blog, “A Guide to Framing Timber Terms.”