For decades, pressure-treated wood has been the default choice for outdoor decking. Its affordability and resistance to insects and rot made it an easy option. However, with growing awareness of its environmental impact, chemical treatments, and relatively short lifespan, homeowners and architects are now seeking a safer, more durable alternative.
One option stands out: Black Locust decking—a hardwood that naturally resists decay, requires no chemical treatments, and lasts for decades with minimal maintenance. This article will compare Black Locust with pressure-treated wood, exploring key aspects like longevity, safety, sustainability, and cost-effectiveness, to help you make the best choice for your next deck.
What Is Pressure-Treated Wood?
Pressure-treated wood is a softwood, usually pine or fir, that has been infused with chemical preservatives under high pressure to extend its lifespan. The treatment process includes:
- Placing the wood inside a sealed pressure chamber
- Forcing chemical preservatives deep into the wood fibers
- Drying the wood to make it construction-ready
Common Chemicals Used in Pressure-Treated Wood
Pressure-treated wood has evolved over time. Older versions contained chromated copper arsenate (CCA), which was phased out for residential use in 2003 due to its high toxicity. Today, pressure-treated wood is typically infused with:
- Alkaline Copper Quaternary (ACQ): A strong fungicide and insecticide with high copper content
- Copper Azole (CA): Similar to ACQ but includes additional fungicides
- Micronized Copper Preservatives (MCA, MCQ): Smaller copper particles to improve absorption
- Creosote (for industrial use): A tar-based preservative used in railroad ties and utility poles
These chemicals help prevent decay, but they come with serious concerns:
- Toxic leaching: Rain and moisture can cause chemicals to seep into the surrounding soil, impacting gardens and groundwater. The EPA has issued warnings about exposure risks.
- Health risks: Children and pets who frequently touch treated wood may absorb trace amounts of chemicals like arsenic and copper.
- Corrosion issues: High copper content can accelerate the deterioration of metal fasteners, requiring additional maintenance over time.
How Long Does Pressure-Treated Wood Last?
The lifespan of pressure-treated wood varies based on exposure and maintenance. On average:
- Above-ground applications (e.g., decks): 10-15 years
- Ground-contact or high-moisture environments: 5-10 years
Although some manufacturers claim pressure-treated wood can last up to 20 years, water infiltration can weaken the wood from the inside, reducing its effectiveness over time.
Black Locust Decking: The Chemical-Free Alternative
Unlike pressure-treated wood, Black Locust decking is naturally durable and rot-resistant—without the need for chemical preservatives. This dense, domestically grown hardwood has been used for centuries in demanding outdoor applications, such as:
- Bridges and boardwalks
- Barns and horse fencing
- Exterior furniture and marine construction
What Makes Black Locust a Superior Choice?
✅ No chemicals, no preservatives – 100% natural
✅ Superior hardness – Janka hardness rating of 1,700+ (vs. pine’s 690) according to the Wood Database
✅ Naturally rot- and insect-resistant – No need for additional treatments
✅ Safe for gardens, children, and pets – No leaching of harmful substances
✅ Long-lasting durability – Can last 40+ years with little maintenance
How Long Does Black Locust Last?
Black Locust is one of the most durable domestic hardwoods, with an expected lifespan of:
- Above-ground applications (e.g., decks, fences, pergolas): 40+ years
- Ground-contact or high-moisture applications: 50+ years
Because it is naturally resistant to moisture and pests, Black Locust does not rely on surface coatings or chemical treatments to extend its lifespan.
Maintenance & Upkeep: Black Locust vs. Pressure-Treated Wood
One of the biggest advantages of Black Locust is its low maintenance requirements.
With Black Locust, homeowners avoid the recurring costs of sealing, staining, and board replacements.
Disposal & Environmental Impact
When pressure-treated wood reaches the end of its lifespan, disposal becomes a major issue.
- Classified as hazardous waste: Many landfills do not accept pressure-treated wood due to its toxic chemicals.
- Burning is dangerous: Treated wood should never be burned, as it releases arsenic and other toxic compounds into the air.
In contrast, Black Locust is 100% biodegradable. At the end of its life, it can be:
- Repurposed for garden beds, furniture, or firewood
- Composted without environmental harm
- Recycled or milled into smaller wood products
Choosing Black Locust means investing in a longer-lasting deck while reducing environmental impact.
Cost Comparison: Is Black Locust Worth the Investment?
Although the initial cost of Black Locust is higher, it proves to be more cost-effective over time.
Over four decades, Black Locust saves homeowners thousands in maintenance and replacement costs.
Final Verdict: Why Black Locust Is the Best Pressure-Treated Wood Alternative
If you want a deck that lasts for generations—without toxic chemicals or high maintenance costs—Black Locust is the clear choice.
✔ Outlasts pressure-treated wood by 35+ years
✔ Zero chemical treatments required
✔ Safe for families, pets, and gardens
✔ Minimal upkeep, no resealing or staining
✔ Better for the environment and long-term savings
💡 Ready to build a deck that lasts a lifetime? Explore our Black Locust decking options and request a sample today!
Why Choose Us? The Original Black Locust Lumber Supplier
At Black Locust Lumber, we are not just another manufacturer—we are the original specialists in Black Locust. While some companies offer it as a side product, we focus exclusively on Black Locust, ensuring the highest quality, best sourcing, and expert craftsmanship.
Our dedication to this one-of-a-kind hardwood makes us the leading supplier for architects, builders, and homeowners looking for the most sustainable and durable wood decking available.
