Description

Key Features

Light-Duty 4x Support

This Simpson Strong-Tie BC40Z post base is built to connect a nominal 4x post to a wood supporting member. It gives you a cleaner, stronger connection than toe-nailing into end grain.

Helps Reduce Splitting

The opposing nail pattern spreads the fastening load in a smarter way. That matters when you want to secure the post without encouraging wood splitting during installation.

ZMAX Coating

The ZMAX finish adds extra corrosion resistance over standard galvanized versions. That makes it a better fit for exposed framing and deck work where hardware sees more moisture.

Overview

The Simpson Strong-Tie BC40Z Post Base is a light-duty post base for attaching a nominal 4x post to a wood supporting member. This is a post base designed for connecting deck posts and other top-supported wood posts while adding uplift and lateral resistance. Model Number BC40Z uses 18 gauge steel with a ZMAX coating for corrosion resistance in tougher jobsite conditions.

In practical terms, this connector gives you a more reliable way to secure a post than angled nailing or driving screws into end grain alone. Simpson Strong-Tie designed the BC series for light-duty applications, and the BC40Z specifically fits nominal 4x posts with dimensions of 3-9/16 inches wide, 3-1/4 inches long, and 2-1/4 inches high. The connection is intended to help keep the post located and tied into the framing below, which is especially useful in deck and patio cover work.

One feature worth paying attention to is the opposing nail pattern. That layout helps reduce the chance of splitting the wood during fastening, which is a common problem when you are trying to lock a post in place near the end of the member. Simpson also states that the connector can achieve its full allowable load using either common nail sizes or pneumatic nail sizes, which gives you some flexibility depending on how your crew installs hardware.

The 18 gauge construction keeps the part easy to handle and suitable for lighter structural connections. This is not the right connector for every post condition, and Simpson is clear about that. BC post bases do not provide adequate resistance to prevent members from rotating about the base, so they are not recommended for non-top-supported installations such as fences or unbraced carports. That limitation matters because it tells you exactly where this hardware belongs and where it does not.

For compatibility, the BC40Z is sized for nominal 4x lumber and is installed with the specified fasteners. Source data calls out 0.162 x 3-1/2 inch nails or 0.162 x 2-1/2 inch nails, and Simpson load data also references Strong-Drive SD10112 fasteners for the BC40 platform. One more important note from the manufacturer: the pilot holes are for manufacturing purposes only and bolts should not be installed in them.

If you are building decks, patio covers, modular structures, or other top-braced wood framing where a light-duty 4x post base makes sense, this connector is the straightforward choice. It is best for carpenters, deck builders, remodelers, and serious DIY users who want a purpose-built post connection instead of improvising one on site.

Secure a 4x Post Without Improvising

This is the kind of hardware that solves a basic framing problem the right way. Instead of relying on angled nails into the post, the base captures the post at the bottom and ties it into the supporting wood member.

• Designed for nominal 4x posts
• Provides uplift and lateral resistance in light-duty connections

Built for Fast, Straightforward Installation

The layout is simple, but the details matter. The opposing nail pattern helps reduce splitting, and the light-gauge design keeps the connector easy to position during install.

• 18 gauge steel construction for light-duty use
• Attains full allowable load with either common nail or pneumatic nail sizes

Know Where It Works Best

The BC40Z is meant for top-supported assemblies, not free-standing posts that can twist at the base. Used in the right application, it is a clean and effective connector for decks and similar framing.

• Not recommended for non-top-supported installations
• Useful for deck posts, patio covers, and modular construction work

Key Specifications

Nominal Post Size	4x
Material Thickness	18 gauge
Finish	ZMAX coating
Width	3-9/16 in.
Length	3-1/4 in.
Height	2-1/4 in.
Application	Factory-built/modular construction
Packaging Quantity	1

Compatibility

Post Size

Fits nominal 4x wood posts.

Fastener Options

Install with specified fasteners, including 0.162 x 3-1/2 inch nails or 0.162 x 2-1/2 inch nails. Simpson load data for the BC40 platform also references SD10112 fasteners.

Installation Note

Pilot holes are for manufacturing purposes only. Do not install bolts in those holes.

Built For

Deck Building Patio Covers Carpentry Construction Remodeling Factory-Built / Modular Construction

Pro Tip

If you are looking at the larger holes and thinking about dropping bolts through them, don’t. On the BC40Z those pilot holes are for manufacturing only, so stick with the specified connector fasteners to get the intended performance.

Warranty & Support

No manufacturer’s warranty is listed for this product in the available source data.

Tool Nut’s Take

Tool Nut’s Take

Simpson Strong-Tie BC40Z Post Base Keeps a Simple Connection Honest

If you need a light-duty way to anchor a 4x post to wood framing, this is the right kind of hardware to use instead of making up your own fastening pattern.

• Who it’s for: Deck builders, carpenters, remodelers, and DIY users working on top-supported 4x post connections.
• Why it stands out: The opposing nail pattern, rated load path, and ZMAX coating make it more useful than a generic bracket or improvised nailing.
• Worth knowing: This is a light-duty connector and it is not the pick for posts that can rotate freely at the base, like fence posts or unbraced carports.

Common Questions

• What size post does this fit? The BC40Z is sized for a nominal 4x wood post.
• What is the base made from? It is made from 18 gauge steel.
• Is this okay for fences or other non-top-supported posts? No. Simpson states that BC post bases are not recommended for non-top-supported installations because they do not provide enough resistance to prevent rotation about the base.
• Can bolts be installed in the pilot holes? No. The manufacturer states that bolts should not be installed in those pilot holes.