The Simpson CPT44Z Concealed Post Base from Simpson combines a knife plate with a standoff base to create a clean, concealed connection between a 4x4 post and a concrete foundation. Designed for both new construction and retrofit applications, this post base delivers a 1 in. standoff height above concrete and a streamlined appearance that keeps hardware hidden - making it a practical choice for decks, pergolas, covered patios, and other permanent outdoor or below-grade structures where a polished finish and code compliance both matter.

Key Features

• 1 in. standoff height above concrete - meets code requirements for permanent structures exposed to weather, water splash, or basement conditions, keeping wood off the slab where moisture damage starts
• Knife plate and standoff base design - achieves a concealed, low-profile appearance so structural hardware stays out of sight without sacrificing load-carrying performance
• Cast-in-place or retrofit anchorage compatibility - works with adhesive or mechanical anchors, giving contractors and DIYers flexibility whether pouring new concrete or anchoring into an existing slab
• ZMAX galvanized finish on base and knife plate - provides enhanced corrosion resistance for exterior use and direct contact with pressure-treated lumber, where standard galvanization may fall short
• 12-gauge base and 10-gauge knife plate construction - heavier-gauge steel at the knife plate adds strength at the critical point of load transfer between the post and the foundation
• Installed with 1/2 in. anchor bolts and supplied galvanized pins - fastening hardware is included with the connector, reducing the guesswork around compatible components

Why This Product

• Concealed look without compromising structure - the knife plate design keeps the connection hidden inside the post, so the finished project looks clean and intentional rather than industrial, with no exposed base plate crowding the post face
• Built-in decay protection at a code-required height - the 1 in. standoff lifts post ends away from direct concrete contact, reducing the risk of moisture-driven rot at one of the most vulnerable points in any post-and-foundation assembly
• Flexible installation for new builds and existing concrete - cast-in-place or retrofit anchorage options mean this base fits naturally into a wide range of project timelines and site conditions without requiring a specialized foundation pour
• ZMAX coating for long-term exterior durability - the extra layer of galvanization is specifically suited for treated-wood applications and wet or weathered environments where standard hardware corrodes prematurely

Specifications

• MPN: CPT44Z
• Brand: Simpson Strong-Tie
• Nominal/Rough Post Size: 4x4
• Coating / Finish: ZMAX
• Gauge: Base 12 ga.; knife plate 10 ga.
• Standoff Height: 1 in.
• Install With: 1/2 in. 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) CPT44Z Concealed Post Base, 1/2 in. diameter galvanized pins (supplied with connector).

Downloads and Resources

• View Spec Sheet

Frequently Asked Questions

Why does the CPTZ post base have a 1 in. standoff height?

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 wood from direct contact with concrete.

What anchorage methods are compatible with the CPT44Z?

The anchorage for the CPTZ 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 ZMAX galvanization used on this post base?

ZMAX galvanization offers extra corrosion resistance, making the CPT44Z well suited for exterior applications and use with treated wood, where standard galvanization may not provide sufficient protection against the elements.

What fasteners are needed to install the CPT44Z?

Installation requires 1/2 in. anchor bolts along with the supplied dowels. The 1/2 in. diameter drift dowels are mechanically galvanized and are included with the connector.

Related Products

• CPT44SS

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