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Simpson ABU44Z 4x4 Adjustable Post Base - Zmax Finish

Simpson ABU44Z 4x4 Adjustable Post Base - Zmax Finish

Regular price $23.77
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The Simpson ABU44Z 4x4 Adjustable Post Base - Zmax Finish is designed to securely attach wood posts to existing concrete, making it an essential component for your construction projects. This versatile post base is ideal for various applications and the additional uplift support makes this a good choice for jobs where high capacity uplift is necessary. Its built-in 1-inch standoff design helps prevent rot at the end of the post, ensuring durability and longevity.

One of the standout features of the ABU Adjustable Post Base is its slotted anchor hole, which allows for precise post placement, making installation more manageable. The post base can be attached using nails or Strong-Drive® SD Connector screws, providing flexibility and ease of use.

This product is intended for use with 4x4 lumber but is also available in other sizes, including double 2x, 4x4, 4x6, and 6x6, for both nominal and rough-cut lumber.


  • Increased Load Capacity: Engineered to withstand higher uplift loads, making it ideal for areas prone to earthquakes or high winds.
  • Versatile Application: Intended for use with 4x4 lumber with a slotted base for adjustable installation.
  • Enhanced Durability: The 1-inch standoff design meets code requirements and helps prevent post rot.
  • Light Corrosion Resistance: Proprietary ZMAX coating applied to the product provides protection against corrosion in most environments.

California Residents: WARNING


Material: Steel
Post Size: 4x4
Fasteners required: - (12) 0.162 x 3-1/2" Nails OR - (2) 1/2" Bolts - (1) 5/8" Concrete Anchor
Finish: ZMAX
Manufacturer name: Simpson Strong-Tie
For Treated Lumber: Yes
Product Guide: View Spec Sheet


-The slot in the base enables flexible positioning around the anchor bolt, making precise post placement easier
-The 1" standoff helps prevent rot at the end of the post and meets code requirements for structural posts installed in basements or exposed to weather or water splash


• Use all specified fasteners.
• Post bases do not provide adequate resistance to prevent members from rotating about the base and therefore are not recommended for non top-supported installations (such as fences or unbraced carports).
• Place the base, load transfer plate and nut on the anchor bolt. Loosely tighten the nut.
• Place the standoff base and then the post in the ABU.
• Fasten using nails or Strong-Drive SD structural connector screws or bolts (ABU88, ABU1010 – SDS optional).

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× WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects and other reproductive harm. For more information visit:

Customer Reviews

Based on 2 reviews
R. Mark St. Laurent
DIY deck project by a homeowner

I used the ABU-44Z for the connection point for the ground contact stair rail post on a deck I am building. Prior to ordering the item I spoke with my local county building inspector/plans inspector and he confirmed that the ABU-44 was acceptable for this function in our county. The caveat was that I was required to use 1/2" diameter bolts driven through the sides of the ABU-44, each of the two surrounding stringers, and the 4x4 post.

The construction of the ABU-44 is solid and heavy duty. I am extremely pleased. But, I would expect nothing less for Simpson. The Simpson Strong Tie products perform as expected. It is nice to see a company taking pride and delivering quality products at at reasonable price. If you have questions call the Simpson 800 customer service number and a technician / product specialist will square you away and offer suggestions. I do not work for Simpson. I am a career fireman/medic.

I used 6" Simpson Strong Tie HD Titen screws to set the ABU-44z into the concrete base that has an overlay of 1" slate slab. The connection was a breeze and is solid. Can you say, "money!"

The connection with the 4x4 post via the 8" x 1/2" galvanized carriage bolts was simple. The connection without the stairs or railings is solid. When the stairs were completed with the treads and railing the assembly as a whole the connection is rock solid.

The inspector commented that that I "did it right".

The team at Fasteners Plus was phenomenal. I have ordered from them several times. Each time the items have arrived quickly withing 2-3 days of me placing the order. I highly recommend both The ABU-44 and Fasters Plus.

Doug Proctor
Great concrete to wood connection for decks.

I have gone to these almost exclusively when building decks. They keep my PT posts off the concrete, and with Fastenal's pricing they are competative with other solutions; assuming you have a good concrete drill.