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RPBZ Retrofit Post Base

The RPBZ retrofit post base is designed to reinforce existing posts and columns. The single, versatile model will fit on any size post consisting of a double 2x4 or larger. RPBZ can also be used to reinforce new post-base connections, such as braced carports, patio covers, decks and other structures. The RPBZ can be installed with the CPS composite plastic standoff to meet a 1" post standoff code requirement. A single RPBZ can be installed on a post that is flush to a corner, and two RPBZs can be installed at away-from-edge conditions to fortify the post-base connection to resist both wind and seismic forces.

Strong-Drive® SDS Heavy-Duty Connector screws install easily and provide excellent holding strength for post-to-flange connections. Additionally, the RPBZ can be purposed as a temporary base fixture for posts when shoring beams. RPBZ comes standard in ZMAX® finish to meet exposure conditions in many environments. See additional Corrosion Information.


  • 12 gauge


  • ZMAX coating


  • Use all specified fasteners; see General Notes.
  • 1/4" x 1 1/2" Strong-Drive SDS Heavy-Duty Connector and base connection fasteners are not provided with RPBZ. Simpson Strong-Tie CPS series composite post standoff sold separately.
  • 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 car ports.

Related Literature

Product Information Table

Fastener Production Information and Stuff & Things
Model No. Ga. Coating/Material Packaging Qty.

Load Tables

    These products are available with additional corrosion protection. Additional products on this page may also be available with this option, check with Simpson Strong-Tie for details.

RPBZ Connector-Only Values

  1. See footnotes below.
RPBZ Corner Installation Post Flush To Edge

RPBZ Anchorage-to-Concrete Values

  1. Allowable load for design shall not exceed minimum of Connector Only Value and Anchorage to Concrete Value.
  2. Allowable connector loads are based on DF/SP lumber. For SPF/HF, multiply table loads by 0.86.
  3. Double 2x4s may be used in lieu of 4x4 post.
  4. For installation on 6x or larger members, if four RPBZ post bases are used, allowable loads may be taken to be 1.5 x the tabulated two-part value.
  5. For installations into concrete, the minimum compressive strength is f'c = 2,500 psi. Designer is responsible for concrete member uplift design.
  6. Away-From-Edge loads require face of wood post to be a minimum of 2 1/2" away from near edge of concrete on all four sides of the post.
  7. Allowable anchorage to concrete uplift and shear loads for the 3/8" diameter anchors are calculated per ACI 318-19. Shear loads assume cracked concrete while uplift loads consider both cracked and uncracked concrete values, and all are qualified for Wind and Seismic Design Categories A&B.
  8. Embedment depth for these post-install anchors must be a minimum of 2 3/4" and are for use with SET-3G™ or AT-XP® structural anchoring adhesives or Titen HD® screw anchors.
  9. Allowable uplift and shear loads for the Titen Turbo™ masonry screws do not carry a particular “cracked” or “uncracked” designation.
  10. Titen Turbo masonry screws and non-stainless-steel Titen HD screw anchors should be used only in interior-dry and non-corrosive environments.
  11. For connection to wood framing, loads are based on penetration of the Strong-Drive® SDS Heavy-Duty Connector screw’s entire threaded section into the main member. If thread penetration into the main member is less than the “Thread Length” as shown in the table for DF/SP, reduce allowable load by 172 lb./in. of thread not in the main member. Use 121 lb./in. for SPF/HF. Exception: installations onto 5/4" southern yellow pine deck boards where screw tips protrude through the backside achieve full load.

Code Reports & Compliance