The Simpson BC40Z BC ZMAX Galvanized Post Base for 4x from Simpson is a light-duty post base connector engineered to secure the bottom of 4x posts or columns to concrete in top-supported applications such as decks and patio covers. Constructed from 18-gauge steel with a ZMAX galvanized finish, this post base delivers a stronger, more dependable connection than angled nailing or screw fastening alone, while offering enhanced corrosion resistance that makes it well-suited for exterior conditions and treated-wood installations.

Key Features

• Positive post-to-deck connection - mechanically secures the base of a 4x post to a wood deck, eliminating the weak points that come with angled nailing or screw fastening alone
• Stronger than angled nailing or screw fastening - provides a more reliable structural connection, giving you greater confidence in the integrity of your deck or patio cover framing
• Reduces post splitting and eliminates end-grain nailing - the bracket design keeps fasteners out of the post end grain, which helps preserve long-term structural performance and reduces the risk of splitting over time
• ZMAX galvanized finish - offers extra corrosion resistance compared to standard galvanized coatings, making this post base a durable choice for exterior applications and installations involving treated lumber
• 18-gauge steel construction - provides a solid, purpose-built connector that meets the demands of light post base applications without unnecessary bulk
• Top-supported installations only - designed specifically for applications such as decks and patio covers where the post is supported from above, ensuring the connector is used within its engineered load path

Why This Product

• Built for exterior durability - the ZMAX galvanized coating goes beyond standard finishes to resist corrosion in outdoor environments and where treated wood is present, helping the connector hold up over the long term without premature degradation
• A smarter alternative to field fastening - rather than relying on angled nails or screws driven into end grain, this post base creates a positive mechanical connection that is both stronger and less likely to cause post splitting at the base
• American-made Simpson quality - manufactured in the United States and backed by Simpson's reputation for structural connectors, this post base is a trusted choice for contractors and serious DIYers working on decks, patio covers, and similar light-frame structures
• Compatible with common jobsite fasteners - installs with 16d common nails or #10 x 1-1/2 in. Strong-Drive SD screws, so you can complete the installation with fastener types already familiar to most builders

Specifications

• MPN: BC40Z
• Brand: Simpson Strong-Tie
• Member Size: 4x
• Width 1: 3-9/16 in.
• Length 1: 3-1/4 in.
• Height 1: 2-1/4 in.
• Gauge: 18
• Coating / Finish: ZMAX
• Install With: 16d common nails or #10 x 1-1/2 in. Strong-Drive SD screws (sold separately)
• Country of Origin: United States

Approved Applications

• Securing posts or columns to concrete for decks and patio covers
• Light post base connections where top-supported installation is present
• Exterior applications and installations involving treated wood, where enhanced corrosion resistance is required

Downloads and Resources

• View Spec Sheet

Frequently Asked Questions

What post size is the BC40Z designed for?

The BC40Z is designed for a nominal 4x post size, making it suitable for standard 4x lumber used in decks, patio covers, and similar light post base applications.

Why is ZMAX galvanization important for this post base?

ZMAX galvanization offers extra corrosion resistance, making the BC40Z especially well-suited for exterior applications and installations that involve treated wood, where standard finishes may degrade more quickly over time.

What fasteners should be used to install the BC40Z?

The BC40Z should be installed with 16d common nails or #10 x 1-1/2 in. Strong-Drive SD screws, as specified by Simpson Strong-Tie for this connector.

Can the BC40Z be used for fences or unbraced carports?

No. The BC40Z is not recommended for non top-supported installations such as fences or unbraced carports, as post bases do not provide adequate resistance to prevent members from rotating about the base in those applications.

Note: Product dimensions and/or nail or screw holes may differ from picture.