The Simpson CPT44SS Concealed Post Base is a stainless-steel post base connector from Simpson engineered for nominal 4x4 posts. Its knife plate and standoff base design delivers a clean, concealed appearance while maintaining a code-compliant 1-in. standoff height above concrete - keeping wood post ends elevated to reduce the risk of decay and satisfy requirements for structures exposed to weather, water splash, or basement conditions. Supplied with 1/2-in. diameter stainless-steel pins, this post anchor is built for demanding environments where standard galvanized hardware falls short.

Key Features

• Knife plate with standoff base design - achieves a concealed, finished look that keeps hardware hidden while still delivering a structurally sound connection for 4x4 posts
• 1-in. standoff height above concrete - meets code requirements for permanent structures exposed to weather, water splash, or basement conditions, and reduces direct contact between wood and concrete to help prevent post-end decay
• Stainless-steel construction throughout - provides high and severe corrosion resistance, making this post base a reliable choice for coastal, wet, or chemically exposed environments where standard hardware would corrode prematurely
• Flexible anchorage options - the base can be installed cast-in-place or retrofit with adhesive or mechanical anchors, giving contractors and builders adaptability for both new concrete pours and existing slab applications
• Supplied stainless-steel pins included - eliminates the need to source separate fasteners and ensures the complete connection uses compatible corrosion-resistant hardware from the start

Why This Product

• Concealed aesthetics without sacrificing performance - the knife plate design hides hardware inside the post for a clean finished appearance, making this connector well suited for visible deck posts, pergola columns, and architectural applications where exposed hardware is undesirable
• Built for high-corrosion environments - full stainless-steel construction, including the supplied connecting pins, means this post base holds up in severe exposure conditions such as coastal settings, poolside structures, and pressure-treated lumber applications requiring corrosion-resistant connectors
• Code-compliant standoff protects the investment in your structure - the 1-in. standoff height satisfies code requirements for weather-exposed and below-grade installations while actively reducing moisture-driven decay at post bases, extending the service life of the supported structure
• Versatile installation for new builds and retrofit projects - cast-in-place or retrofit anchorage compatibility means this concealed post anchor fits a wide range of project types, from new construction footings to post replacement work on existing concrete

Specifications

• MPN: CPT44SS
• Brand: Simpson Strong-Tie
• Nominal/Rough Post Size: 4x4
• Material: Stainless Steel
• Finish: Stainless Steel
• Gauge: Base 12 ga.; knife plate 10 ga.
• Standoff Height: 1 in.
• Install With: 1/2-in. stainless-steel anchor bolts and supplied dowels
• Width: 3-1/2 in.
• Length: 3-1/2 in.
• Country of Origin: United States

What's Included

Each pack contains (1) CPT44SS Concealed Post Base, 1/2-in. diameter stainless-steel pins (supplied).

Downloads and Resources

• Post Size: 4X4Fasteners required: (2) 1/2" Concrete AnchorsLength: 3-1/2"Manufacturer name: Simpson Strong-TieView Spec Sheet

Frequently Asked Questions

Why is a 1-in. standoff height important for this post base?

The 1-in. standoff height is code-required when supporting permanent structures that are exposed to weather or water splash, or in basements. It also reduces the potential for decay at post or column ends by keeping the wood member elevated above the concrete surface.

What post size is the CPT44SS designed for?

The CPT44SS is designed for a nominal 4x4 post size.

What anchorage options are available for the CPT44SS?

The anchorage for the CPT44SS can be either cast-in-place or retrofit with adhesive or mechanical anchors, providing flexibility for both new construction and existing concrete applications.

Why is stainless steel used for the CPT44SS, and what fasteners are required?

Stainless steel is used to provide high and severe corrosion resistance, making the CPT44SS suitable for demanding outdoor and moisture-prone environments. It is installed with 1/2-in. stainless-steel anchor bolts and the supplied stainless-steel dowels to maintain corrosion resistance throughout the entire connection.

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