The Benefits of LOSP Timber

Why Use LOSP Treated Timber

LOSP (Light Organic Solvent Preservative) timber is a common timber used in both structural and non-structural applications. Known for its durability and long-term performance in outdoor and framing applications, LOSP timber is often used in pergolas, fascia, balustrades, handrails, outdoor staircases, weatherboards, framing, decking substrates and joinery. But what exactly is LOSP timber, and how does it compare to other timber treatments?

What Is LOSP Timber?

LOSP stands for Light Organic Solvent Preservative. It’s a treatment method used to protect softwood and susceptible hardwood timbers from decay, termites and fungal attack. Unlike water-based treatments, LOSP uses a solvent to carry the preservative deep into the timber.

Key Benefits of LOSP Timber

LOSP treated timber offers several key advantages:

• Dimensional Stability: Because LOSP does not use water, it doesn’t cause the timber to swell or warp during treatment. This results in a more stable product
• Paint-Friendly Surface: LOSP treated timber is commonly used where a painted finish is required. It holds paint better and lasts longer compared to some other treatments
• Lightweight and Easy to Work With: Its stability and dry state make it easier to cut, drill, and fasten without compromising performance
• Fungal Resistance: LOSP treatment includes fungicides that protect the timber from decay, preserving its integrity
• Termite Resistance: This treatment protects timber from termites and borers, ensuring peace of mind and long-term protection
• Low Environmental Impact: LOSP is considered less hazardous to handle than traditional CCA-treated timber, especially in residential settings.

Is LOSP Better Than CCA?

LOSP and CCA (Chromated Copper Arsenate) are both effective timber treatments, but they serve different purposes. LOSP is better suited for above-ground, painted or finished applications, where visual appeal matters. CCA, on the other hand, is a heavy-duty treatment more suitable for commercial or in-ground applications and is not suitable for household building and renovations.

CCA is often used for landscaping, fencing and jetty piles. It must not be used in decking, playground equipment, outdoor seating, handrails, patios, verandahs and furniture.

Note: CCA treated timber is not intended to be burnt or used in areas that experience frequent close proximity to humans, including near edible plants.

Can LOSP Timber be Used In-Ground?

LOSP timber is not suitable for in-ground contact. It is designed specifically for above-ground use, such as:

• Exterior cladding
• Fascia boards
• Pergolas
• Framing
• Decking substrates
• Timber window frames
• Joinery
• Decorative finishes such as finials

If your project involves posts, retaining walls, or any in-ground applications, opt for H4 or higher-rated CCA or ACQ treated timber.

How Long Does LOSP Last?

When used in the right conditions (above-ground and protected from constant moisture), LOSP timber can last 15 to 25 years or more. However, the correct installation, sealing, and on-going maintenance will extend its lifespan. Prime and paint LOSP treated timber after installation to protect it from weathering.

Is LOSP Timber Strong?

Yes, LOSP treated timber retains the natural strength of the timber species used. It doesn’t affect structural integrity. In fact, because the treatment doesn’t distort the timber’s shape, LOSP timber is often stronger in terms of stability.

Bowens Range of LOSP Timber Products

Bowens stocks and supplies a wide range of LOSP timber including LVL timber, GluLam beams, pine framing, timber screening and more. Available in a variety of sizes, lengths and profiles, discover LOSP timber online or in-store at one of our conveniently located stores in Melbourne or regional Victoria today.