{"product_id":"simpson-strong-tie-zmax-galvanized-concealed-post-base-for-8x8-cpt88z","title":"Simpson Strong-Tie ZMAX Galvanized Concealed Post Base for 8x8 (CPT88Z)","description":"\u003csection data-aplus\u003e\n  \u003cdetails id=\"product-features\" class=\"acc\" open\u003e\n    \u003csummary\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"features\"\u003e\n        \u003cdiv class=\"card\"\u003e\n          \u003cdiv class=\"card-inside\"\u003e\n            \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/handle.svg\" alt=\"handle\" class=\"aplusicon\"\u003e\n          \u003c\/div\u003e\n          \u003cdiv\u003e\u003cstrong\u003eConcealed Connection\u003c\/strong\u003e\u003c\/div\u003e\n          \u003cdiv class=\"feature-card\"\u003eThe knife-plate design hides most of the hardware inside the post, so you get a cleaner finished look than an exposed post base. That matters on decks, covered patios, and other visible structural posts.\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"card\"\u003e\n          \u003cdiv class=\"card-inside\"\u003e\n            \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/depth.svg\" alt=\"depth\" class=\"aplusicon\"\u003e\n          \u003c\/div\u003e\n          \u003cdiv\u003e\u003cstrong\u003e1 Inch Standoff\u003c\/strong\u003e\u003c\/div\u003e\n          \u003cdiv class=\"feature-card\"\u003eThe built-in standoff keeps the post end 1 inch above concrete, which is code-required for many weather-exposed applications and helps reduce rot at the base.\u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"card\"\u003e\n          \u003cdiv class=\"card-inside\"\u003e\n            \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/material.svg\" alt=\"material\" class=\"aplusicon\"\u003e\n          \u003c\/div\u003e\n          \u003cdiv\u003e\u003cstrong\u003eBuilt for 8x8 Posts\u003c\/strong\u003e\u003c\/div\u003e\n          \u003cdiv class=\"feature-card\"\u003eThis Simpson Strong-Tie concealed post base is sized for nominal 8x8 posts and uses supplied 1\/2 inch drift dowels with anchor-based concrete attachment for retrofit or cast-in-place footing work.\u003c\/div\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-overview\" class=\"acc\" open\u003e\n    \u003csummary\u003e\u003ch2\u003eOverview\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\" data-product-summary\u003e\n      \u003cp\u003eThe Simpson Strong-Tie CPT88Z concealed post base is a retrofit post base for connecting a nominal 8x8 wood post to concrete while keeping the connection mostly hidden inside the post. This is a post base designed for deck and post-to-footing structural connections. Model Number: CPT88Z. If you want a cleaner-looking post connection without giving up the required separation from concrete, this is the style of connector you use.\u003c\/p\u003e\n      \u003cp\u003eWhat sets the CPT88Z apart is the concealed knife-plate layout. Instead of wrapping the outside of the post with visible steel, the connector uses an internal plate and a standoff base so the finished post looks cleaner once installed. That makes it a solid fit for jobs where appearance matters, especially exposed deck posts, porch posts, and other permanent structures where bulky exposed hardware would stand out.\u003c\/p\u003e\n      \u003cp\u003eThe 1 inch standoff height is a real-world feature, not just a line in the spec sheet. It lifts the end of the post above the concrete surface to help limit moisture exposure and reduce the chance of decay at the post end. Simpson Strong-Tie specifically calls out this standoff as code-required when supporting permanent structures exposed to weather, water splash, or basement conditions, so it solves both a durability issue and a compliance issue at the same time.\u003c\/p\u003e\n      \u003cp\u003eMaterial and finish matter on connectors like this, and the CPT88Z is built for that environment. The knife plate, washers, and standoff base are made from ZMAX galvanized steel, and the standoff base also gets a textured flat black powder-coat finish for appearance. The supplied 1\/2 inch drift dowels are mechanically galvanized. For exterior work and treated lumber applications, that corrosion-resistant finish is one of the reasons this connector gets specified in the first place.\u003c\/p\u003e\n      \u003cp\u003eInstallation is more involved than a simple saddle-style base, but that is the tradeoff for the concealed look. The post needs drilled 1\/2 inch holes and a 3\/16 inch slot cut into the end so the knife plate can fit inside properly. The connector is then anchored to concrete with 1\/2 inch anchor bolts, and the post is secured with the supplied dowels. Simpson Strong-Tie also notes that anchorage can be cast-in-place or retrofit using adhesive or mechanical anchors, which gives the CPT88Z flexibility for both new work and upgrade jobs.\u003c\/p\u003e\n      \u003cp\u003eFrom a jobsite standpoint, this is a wood-to-concrete retrofit base made for top-supported structural posts, not free-standing posts that need base rotational restraint on their own. Simpson Strong-Tie specifically notes that post bases do not provide adequate resistance to prevent members from rotating about the base and are not recommended for non-top-supported installations such as fences or unbraced carports. That is an important distinction if you are choosing hardware for a structural inspection or a repair scope.\u003c\/p\u003e\n      \u003cp\u003eThe CPT88Z is a good fit for deck builders, remodelers, framing contractors, and serious DIY users working on permanent exterior structures where the post connection will stay visible. If the goal is maximum simplicity, a standard exposed post base may be faster. If the goal is a cleaner finish, code-required standoff, and a connector sized specifically for nominal 8x8 posts, the Simpson Strong-Tie CPT88Z concealed post base makes a strong case.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-benefits\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eCleaner Finished Post Detail\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"row\"\u003e\n        \u003cdiv class=\"img\"\u003e\n          \u003cimg src=\"https:\/\/ssttoolbox.widen.net\/content\/sqbowftgwo\/jpeg\/C_CPTZ_ProdIll_Ill_Prod_ConcealedPostTie-Components_C0.jpeg?position=c\u0026amp;color=ffffffff\u0026amp;u=cjmyin\" alt=\"Simpson Strong-Tie CPT88Z concealed post base component layout showing the knife plate, standoff base, washers, and drift dowels used in an 8x8 post-to-concrete connection\" class=\"tnblock-img\"\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"copy\"\u003e\n          \u003cp\u003eThis connector is built around a concealed knife plate and separate standoff base, which is what gives the assembly its cleaner look once the post is installed. You get the function of a structural post base without as much exposed steel showing on the finished work.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003eDesigned for nominal 8x8 posts\u003c\/li\u003e\n            \u003cli\u003eSupplied with (3) 1\/2 inch diameter dowel pins\u003c\/li\u003e\n          \u003c\/ul\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-benefits-2\" class=\"acc flip\"\u003e\n    \u003csummary\u003e\u003ch2\u003eKeeps the Post Off the Concrete\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"row\"\u003e\n        \u003cdiv class=\"img\"\u003e\n          \u003cimg src=\"https:\/\/ssttoolbox.widen.net\/content\/dw6j0xqnpx\/jpeg\/C_CPTZ_InstSeq_Ill_Inst_ConcealedPostTie_CN_STEP04.jpeg?position=c\u0026amp;color=ffffffff\u0026amp;u=cjmyin\" alt=\"Simpson Strong-Tie CPT88Z concealed post base installed on concrete with anchor bolts, showing the standoff base and knife plate before the 8x8 post is set in place\" class=\"tnblock-img\"\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"copy\"\u003e\n          \u003cp\u003eThe 1 inch standoff is one of the big reasons to use this style of post base. It helps keep moisture from sitting at the end grain of the post and supports code-driven spacing requirements for permanent structures exposed to the weather.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003e1 inch standoff height above concrete\u003c\/li\u003e\n            \u003cli\u003eAnchorage can be cast-in-place or retrofit with adhesive or mechanical anchors\u003c\/li\u003e\n          \u003c\/ul\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-benefits-3\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eLayout Matters on Retrofit Work\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"row\"\u003e\n        \u003cdiv class=\"img\"\u003e\n          \u003cimg src=\"https:\/\/ssttoolbox.widen.net\/content\/ya7djqv9jx\/jpeg\/C_CPTZ_InstIll_Ill_Instld_ConcealedPostTie-CornerFlushEdge_CY.jpeg?position=c\u0026amp;color=ffffffff\u0026amp;u=cjmyin\" alt=\"Simpson Strong-Tie CPT88Z concealed post base installation diagram showing corner flush edge placement and knife plate location in a concrete footing for an 8x8 post\" class=\"tnblock-img\"\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"copy\"\u003e\n          \u003cp\u003eThis is not a guess-and-go connector. The anchor and slot layout need to be right, especially on edge and corner conditions, which is why this style is popular on planned structural work instead of rough patch jobs.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003eUses 1\/2 inch anchor bolts with supplied dowels\u003c\/li\u003e\n            \u003cli\u003eSimpson Strong-Tie provides specific installation guidance for edge and corner conditions\u003c\/li\u003e\n          \u003c\/ul\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-whats-included\" class=\"acc\" open\u003e\n    \u003csummary\u003e\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"tnincluded-wrapper\"\u003e\n        \u003cul\u003e\n          \u003cli\u003e(1) Simpson Strong-Tie CPT88Z concealed post base\u003c\/li\u003e\n          \u003cli\u003e(3) 1\/2 inch diameter drift dowels\u003c\/li\u003e\n          \u003cli\u003eWashers\u003c\/li\u003e\n        \u003c\/ul\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"included-note\"\u003e\n        \u003cp\u003eAnchor bolts are required for installation and are specified separately by the designer.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-key-specifications\" class=\"acc\" open\u003e\n    \u003csummary\u003e\u003ch2\u003eKey Specifications\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003ctable class=\"aplusspecs\"\u003e\n        \u003ctr\u003e\n          \u003cth\u003eApplication\u003c\/th\u003e\n          \u003ctd\u003eDecks, post-to-footings\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003ePost Size\u003c\/th\u003e\n          \u003ctd\u003eNominal 8 x 8\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eMaterials Connected\u003c\/th\u003e\n          \u003ctd\u003eWood to concrete (retrofit)\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eStandoff Height\u003c\/th\u003e\n          \u003ctd\u003e1 in\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBase Gauge\u003c\/th\u003e\n          \u003ctd\u003e12 gauge\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eKnife Plate Gauge\u003c\/th\u003e\n          \u003ctd\u003e10 gauge\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eAnchor \/ Dowel Size\u003c\/th\u003e\n          \u003ctd\u003e1\/2 in\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eWeight\u003c\/th\u003e\n          \u003ctd\u003e4.88 lbs\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eActual Width\u003c\/th\u003e\n          \u003ctd\u003e7.25 in\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eActual Depth\u003c\/th\u003e\n          \u003ctd\u003e7.25 in\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eFinish\u003c\/th\u003e\n          \u003ctd\u003eZMAX galvanized steel with textured flat black powder-coat standoff base\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003cth\u003eMaterial\u003c\/th\u003e\n          \u003ctd\u003eSteel\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/table\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-compatibility\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eCompatibility\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"compat-list\"\u003e\n        \u003cdiv class=\"compat-row\"\u003e\n          \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/size.svg\" alt=\"size\" class=\"icon-sm\"\u003e\n          \u003cdiv\u003e\n            \u003cstrong\u003ePost Size\u003c\/strong\u003e\n            \u003cdiv class=\"compat-detail\"\u003eSized for nominal 8x8 wood posts.\u003c\/div\u003e\n          \u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"compat-row\"\u003e\n          \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/material.svg\" alt=\"material\" class=\"icon-sm\"\u003e\n          \u003cdiv\u003e\n            \u003cstrong\u003eConnection Type\u003c\/strong\u003e\n            \u003cdiv class=\"compat-detail\"\u003eDesigned for wood-to-concrete post-to-footing connections.\u003c\/div\u003e\n          \u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"compat-row\"\u003e\n          \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/diameter.svg\" alt=\"diameter\" class=\"icon-sm\"\u003e\n          \u003cdiv\u003e\n            \u003cstrong\u003eFastener Interface\u003c\/strong\u003e\n            \u003cdiv class=\"compat-detail\"\u003eInstalls with 1\/2 inch anchor bolts and supplied 1\/2 inch drift dowels. Structural-quality through bolts may be used as an alternative to the supplied dowels where listed by Simpson Strong-Tie.\u003c\/div\u003e\n          \u003c\/div\u003e\n        \u003c\/div\u003e\n        \u003cdiv class=\"compat-row\"\u003e\n          \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/compliance.svg\" alt=\"compliance\" class=\"icon-sm\"\u003e\n          \u003cdiv\u003e\n            \u003cstrong\u003eAnchorage Options\u003c\/strong\u003e\n            \u003cdiv class=\"compat-detail\"\u003eCan be used with cast-in-place anchorage or retrofit anchorage using adhesive or mechanical anchors, depending on the project design.\u003c\/div\u003e\n          \u003c\/div\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-applications-uses\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eBuilt For\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"tags\"\u003e\n        \u003cspan class=\"tag\"\u003eDeck Building\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003ePost-to-Footing Connections\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eExterior Structural Posts\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eRemodeling\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eGeneral Contracting\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eCarpentry\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eWood Construction\u003c\/span\u003e\n        \u003cspan class=\"tag\"\u003eRetrofit Work\u003c\/span\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-pro-tips\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003ePro Tip\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"tip-row\"\u003e\n        \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/specs.svg\" alt=\"specs\" class=\"icon-lg\"\u003e\n        \u003cp class=\"tip-text\"\u003eBefore you cut the post slot, use the CPTZ knife blade as the template for your hole layout just like Simpson Strong-Tie recommends. It is the easiest way to keep the drilled holes and the slot aligned so the post drops on clean instead of fighting the hardware during install.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-tool-nut-take\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eTool Nut's Take\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cdiv class=\"eyebrow\"\u003eTool Nut's Take\u003c\/div\u003e\n      \u003ch3\u003eSimpson Strong-Tie CPT88Z concealed post base for clean-looking structural posts\u003c\/h3\u003e\n      \u003cp\u003eIf you want an 8x8 post connection that looks a lot better than a standard exposed base and still gives you the standoff you need over concrete, this is the right style of hardware.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWho it's for:\u003c\/strong\u003e Deck builders, remodelers, and contractors installing top-supported 8x8 structural posts where appearance matters.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWhy it stands out:\u003c\/strong\u003e The concealed knife plate gives you a cleaner finished post, and the 1 inch standoff handles the moisture and code side of the job at the same time.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWorth knowing:\u003c\/strong\u003e This one takes layout and post prep, so it is not the fastest base to install. Also, like other post bases, it is not intended to solve rotation issues in non-top-supported installations.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails id=\"product-faqs\" class=\"acc\"\u003e\n    \u003csummary\u003e\u003ch2\u003eCommon Questions\u003c\/h2\u003e\u003c\/summary\u003e\n    \u003cdiv class=\"acc-body\"\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eWhat post size does the CPT88Z fit?\u003c\/strong\u003e It is designed for nominal 8x8 wood posts.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCan this post base be used for retrofit work?\u003c\/strong\u003e Yes. Simpson Strong-Tie lists the CPTZ series for retrofit post base use and states that anchorage can be cast-in-place or retrofit with adhesive or mechanical anchors.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eDoes it keep the post off the concrete?\u003c\/strong\u003e Yes. The connector provides a 1 inch standoff above concrete.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eIs this a good choice for a free-standing fence or unbraced carport post?\u003c\/strong\u003e No. Simpson Strong-Tie notes that post bases do not provide adequate resistance to prevent rotation at the base and are not recommended for non-top-supported installations.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e","brand":"Simpson Strong-Tie","offers":[{"title":"Default Title","offer_id":52999300645158,"sku":"CPT88Z","price":87.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0933\/1582\/5958\/files\/CPT88Z_00707392577607_Product_Photo_01_0c44bd17-6d3c-4916-b59e-92e1acfd904a.jpg?v=1779135461","url":"https:\/\/www.toolnut.com\/products\/simpson-strong-tie-zmax-galvanized-concealed-post-base-for-8x8-cpt88z","provider":"Tool Nut","version":"1.0","type":"link"}