The Simpson BC40 4x Post Base is an 18-gauge steel connector from Simpson designed to securely anchor the bottom of 4x posts or columns to a wood deck surface - delivering a stronger, more reliable connection than angled nailing or screw fastening alone. Built for light base applications such as decks and patio covers, this post base features a G90 zinc galvanized finish that stands up to the moisture exposure common in outdoor structural work.

Key Features

• Provides a positive connection for a post to a wood deck - gives you a mechanically secure anchor point rather than relying on friction or fastener angle alone, adding confidence to every structural connection
• Stronger than angled nailing or screw fastening - the bracket-based design transfers loads more efficiently, improving overall connection integrity in deck and patio cover framing
• Reduces the chance of the post splitting and eliminates nailing into end grain - protects the post from common installation damage, extending the life of the connection and the lumber itself
• Made from 18-gauge steel - provides a solid, rigid base that holds its shape under load without adding excessive bulk to the installation
• Galvanized (G90) for extra corrosion resistance - the zinc galvanized coating helps the base resist rust and deterioration in outdoor environments where moisture is a regular concern
• Fits nominal 4x post size - sized to pair directly with standard 4x lumber, making it a straightforward fit for common deck and patio cover framing projects
• Not recommended for non top-supported installations such as fences or unbraced carports - knowing the correct application upfront helps you choose the right connector and avoid callbacks or code issues

Why This Product

• A more reliable alternative to toe-nailing - rather than driving fasteners at an angle into end grain, this post base wraps the base of the post in a formed steel bracket, creating a stronger and more consistent connection for decks and patio covers
• G90 galvanized protection built for outdoor use - the zinc galvanized finish is specifically suited for the exposed conditions of exterior structural applications, helping the connector resist corrosion over time without requiring additional treatment
• Engineered by a trusted name in structural connectors - Simpson has a long-standing reputation in the construction industry for producing code-recognized hardware, so specifiers and builders can install with confidence
• Protects your lumber investment - by eliminating end grain nailing and reducing splitting risk, this post base helps preserve the structural integrity of the post itself, not just the connection point

Specifications

• MPN: BC40
• 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: Zinc Galvanized, G90
• Install With: Install with 16d common nails or #10 x 1-1/2 in. Strong-Drive SD screws (sold separately)
• Country of Origin: United States

Downloads and Resources

• View Spec Sheet

Frequently Asked Questions

What size post is the BC40 designed for?

The BC40 is designed for a nominal 4x post size, making it suitable for standard 4x lumber used in decks, patio covers, and similar light structural applications.

What fasteners should be used to install the BC40?

Install with 16d common nails or #10 x 1-1/2 in. Strong-Drive SD screws. Always use all specified fasteners to ensure a proper, code-compliant connection.

Can the BC40 be used for fences or unbraced carports?

No. The BC40 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.

Why is the G90 galvanized coating important?

The G90 zinc galvanized finish provides extra corrosion resistance, making the BC40 well suited for outdoor applications such as decks and patio covers where exposure to moisture is a concern.