Simpson Strong-Tie CPTZ Concealed Post Base - 4x4
The CPTZ concealed post base provides a clean, concealed look while providing a 1" standoff height above concrete. The 1" standoff reduces the potential for decay at the post end and satisfies code requirements for posts that are exposed to weather, water splash or in basements. It is part of a system of concealed connectors that includes the CBTZ and CJT.
- The CPTZ is tested and load rated for uplift, download and lateral load.
- Simpson Strong-Tie saves installers time by providing all the necessary components to make the post connection in one box (anchors not included).
- There are two anchorage solutions available. See tables for information.
- Solutions have been calculated per ACI 318 to determine their allowable load in different concrete configurations.
Knife plate, washers and standoff base are ZMAX®-galvanized steel. The standoff base has an additional textured, flat black powder-coat finish for aesthetic purposes. The 1/2"-diameter drift dowels are mechanically galvanized in accordance with ASTM B695, Class 55. If substituting 1/2"-diameter bolts, a hot-dip galvanized finish is recommended. Some available in stainless steel (see table).
- Use knife blade portion of CPTZ as a template to mark dowel/bolt locations on post.
- Drill 1/2"-diameter holes perpendicular to post at marked locations.
- Cut a 3/16"-wide slot in the end of the post. Cut slot on face adjacent to the one with the holes. If using a circular saw, cut the slot roughly 6 1/2" up the post. Test that the knife blade slides freely in the slot.
- Install the knife blade portion of the connector on the anchor bolts and then place the supplied washers over top of the connector’s tabs and on the anchor bolt. Use nuts to attach the knife blade and washers to the anchors.
- The Designer must specify anchor bolt type, length and embedment.
- Slide the standoff base on to the knife blade assembly.
- Stand the post on the knife blade and drive in the dowels supplied with the connector.
- 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).