Description

Key Features

Stainless Steel Build

Made from stainless steel for high corrosion resistance in exposed outdoor installs, coastal areas, and other places where a standard coated base is not the right call.

Built-In 1 Inch Standoff

The raised base helps keep the post off the concrete so water is less likely to sit at the end grain. That matters for long-term durability, especially on decks and exposed structures.

Adjustable Post Placement

The Simpson Strong-Tie ABU66SS adjustable post base uses a slotted anchor hole to give you some setup flexibility around the anchor bolt, which makes it easier to line up a 6×6 post where it needs to land.

Overview

The Simpson Strong-Tie ABU66SS Adjustable Post Base is a stainless steel retrofit post base for attaching a nominal 6×6 wood post to existing concrete. This is a post base designed for securing structural wood posts to concrete footings and slabs. Model Number: ABU66SS. It is built for high-capacity post-to-concrete connections where corrosion resistance, uplift performance, and cleaner post alignment all matter.

What makes the ABU design useful on the job is the combination of strength and install flexibility. The base has a slotted anchor hole, so you have some room to work around the anchor location when setting the post base. That can save time when the concrete anchor is already in place and the post needs to finish in a precise spot for beams, rails, or framing layout.

The built-in 1 inch standoff is one of the details that matters more than it looks on paper. By lifting the post off the concrete, it helps reduce direct moisture contact at the end of the post. For decks, covered exterior structures, basements, and other areas that see splash, damp conditions, or weather exposure, that stand-off design helps support a longer-lasting installation.

This ABU66SS version is made from stainless steel, which makes it the better choice when you are working with pressure-treated lumber or installing in corrosive environments. If the job is near water, in a coastal area, or just exposed year-round, stainless is often the right spend up front instead of replacing rusted hardware later.

For fastening, the post base is designed to attach to the post with nails, Strong-Drive SD Connector screws, or bolts, and to the concrete with a 5/8 inch anchor. Published fastener requirements for this size call for either twelve 0.162 x 3-1/2 inch nails or two 1/2 inch bolts at the post, plus one 5/8 inch concrete anchor at the base. As with any structural connector, the correct fasteners in the correct holes are what get you the rated performance.

Size-wise, this model is built for a nominal 6×6 post and measures 5-1/2 inches wide, 5 inches long, and 6-1/16 inches high, with a 1-3/4 inch stand-off. The base uses 12-gauge steel and 10-gauge straps, so it is not light-duty hardware. This is the kind of connector you use when the post is doing real structural work, not when you just need a decorative bracket.

The ABU series is intended for top-supported structural posts. Simpson specifically notes that post bases like this are not recommended for non-top-supported installations where the member can rotate at the base, such as fences or unbraced carports. Used in the right application, though, it is a solid choice for deck framing, porch posts, pavilion posts, and other load-bearing post-to-footing connections.

Built for Real Post-to-Concrete Work

This connector is meant for structural post support on existing concrete where accuracy and durability both matter. The slotted base gives you some adjustment room at the anchor, which helps when layout is tight and you need the post to finish exactly where the framing says it should.

• Designed for nominal 6×6 wood posts in post-to-footing applications
• 1 inch stand-off helps keep the post above the concrete surface

What’s in the Box

• (1) Simpson Strong-Tie ABU66SS Adjustable Post Base for 6×6 posts

Concrete anchor and post fasteners are required but not included.

Key Specifications

Nominal Post Size	6 x 6
Material	Stainless Steel
Width (in.)	5-1/2 in.
Length (in.)	5 in.
Height (in.)	6-1/16 in.
Stand-Off Height (in.)	1-3/4 in.
Steel Gauge	Base 12 ga.; Strap 10 ga.
Concrete Anchor Diameter	5/8 in.

Compatibility

Post Size

Designed for nominal 6 x 6 wood posts.

Concrete Anchor

Uses one 5/8 in. concrete anchor for base attachment.

Post Fasteners

Post can be fastened with nails, Strong-Drive SD Connector screws, or bolts as specified by Simpson Strong-Tie.

Treated Lumber Use

Suitable for treated lumber and corrosive environments where stainless steel hardware is the preferred match.

Built For

Deck Framing Post-to-Concrete Connections Outdoor Structures General Contracting Remodeling Construction Pressure-Treated Lumber Corrosion-Prone Environments

Pro Tip

Before you lock in the anchor, dry-fit the ABU66SS and use the slotted base hole to dial in your post location. Also keep the base anchor projection under 1 inch above the concrete so it does not interfere with the standoff during install.

Warranty & Support

Manufacturer warranty listed as 12 months.

Tool Nut’s Take

Tool Nut’s Take

Simpson Strong-Tie ABU66SS Adjustable Post Base for tough outdoor post work

If you are setting a real 6×6 structural post on existing concrete and corrosion is a concern, this is the kind of hardware you buy once and stop worrying about.

• Who it’s for: Contractors, deck builders, and serious DIYers installing load-bearing 6×6 posts on concrete footings or slabs.
• Why it stands out: Stainless steel construction, a built-in stand-off, and the slotted anchor hole give you a better mix of durability and install forgiveness than a basic fixed base.
• Worth knowing: This is a structural post base, not a cure-all bracket. You still need the correct anchor and fasteners, and it is meant for top-supported posts, not free-standing fence-style installs.

Common Questions

• What size post does this fit? This model is designed for a nominal 6 x 6 wood post.
• Can it be used on existing concrete? Yes. The ABU series is designed to attach wood posts to existing concrete in retrofit and other post-to-footing applications.
• Why does this base have a stand-off? The built-in 1 inch stand-off helps keep the post elevated above the concrete, which supports code compliance in certain applications and helps reduce moisture exposure at the base of the post.
• Is this a good choice for treated lumber or outdoor exposure? Yes. This ABU66SS version is stainless steel and is intended for applications where corrosion resistance matters.