Summary: We use CCA .60-treated lumber for dock framing because it provides superior durability and protection in constant water exposure. For decking, we use Heavy-Duty ESR-2240 .23 MCA-treated lumber to meet modern building code requirements. This combination ensures our docks are durable, compliant, and built for long-term performance.
Boat Dock Building Materials and Regulations
Boat dock building materials and regulations have changed over time. In the past, we used different treated lumber products depending on availability, project requirements, and environmental rules. Lumber used around water is regulated by agencies such as the EPA, state environmental departments, and local permitting authorities.
Because standards and treatments have evolved, we have now standardized our structural dock lumber to the better CCA .60 (Chromated Copper Arsenate) treatment for long-term performance in demanding water environments.
CCA Dock Frames vs MCA Treated Dock Frames
Some docks are framed with MCA (copper-based) treated lumber rather than CCA (arsenic-based) treated lumber. While MCA works well for many above-ground deck structures, it is not designed for the same level of water exposure as CCA.
CCA .60 Dock Frames (Arsenic-Based Treatment)
- Heavy-duty marine level treatment
- Designed for constant moisture exposure
- Proven long-term performance in dock structures
- Greater resistance to rot and biological decay
MCA Treated Dock Frames (Copper-Based Treatment)
- Designed mainly for above-ground deck construction
- Lower preservative retention compared to marine CCA levels
- Suitable for decking surfaces, but less ideal for structural dock framing
Because dock framing is constantly exposed to water, humidity, and harsh environmental conditions, CCA .60 provides significantly better long-term protection and durability for the dock’s structural frame. MCA treatments are better suited for decking surfaces where building codes restrict the use of arsenic-based treatments.
Why We Use CCA .60 Instead of .40
Not all pressure-treated lumber is treated to the same level. One of the biggest differences is retention, which measures how much preservative is retained in the wood.
CCA .40 is commonly used for general exterior applications. It offers protection against rot and insects but is typically intended for less demanding conditions.
CCA .60 is a heavier treatment level designed for tougher exposure, especially around constant moisture and water. Compared to .40, it provides:
- Greater resistance to rot and decay
- Better durability in wet environments
- Longer service life for dock framing
- Stronger long-term value for customers
Because docks live in a harsh environment, CCA .60 is the better choice for structural dock lumber. That is why it is now the standard lumber treatment we use.
Decking Requirements – Heavy Duty ESR-2240 .23 MCA Treatment
For our dock decking, regulations prohibit the use of arsenic-treated boards in many applications. Because of this, we use Heavy-Duty ESR-2240 .23 MCA-treated lumber, which is the next best approved treatment when arsenic-based CCA cannot be used.
MCA stands for Micronized Copper Azole, a wood preservative system used in modern pressure-treated lumber. The .23 retention level is intended for heavy-duty above-ground applications where the wood is exposed to weather and moisture, including decking applications.
ESR-2240 is an ICC Evaluation Service report, meaning the product has been reviewed for compliance with recognized building code standards. In simple terms, it confirms the material is approved for the application it is being used for.
This decking treatment offers several advantages:
- Protection against fungal decay and insect damage
- Compliance with modern code requirements
- Performance suited for exterior deck surfaces
- Compatibility with many modern deck construction practices
In short, our framing and decking are treated differently because they serve different purposes and must meet different standards. CCA decking can be used when permitted.
Important Notice About CCA Use
CCA-treated lumber is not allowed in every location. Some lakes, reservoirs, and regulated bodies of water restrict or prohibit the use of CCA-treated materials.
Because those rules vary by location, it is the customer’s responsibility to verify whether CCA-treated lumber is permitted in their specific body of water, jurisdiction, or permitting authority before installation.
If CCA is not allowed in a particular location, alternative MCA-treated materials may be required.
Built for Long-Term Performance
We use CCA .60-treated structural lumber because it provides our customers with a stronger, longer-lasting dock frame than CCA .40-treated lumber or MCA-treated lumber. We believe the cost upgrade to the better treatment is money well spent for the customer.
For decking, we use Heavy-Duty ESR-2240 .23 MCA-treated lumber to meet legal and performance requirements. That combination helps us build docks that are durable, code-compliant, and built for long-term value.
