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# Anchoring a Pergola Column to Concrete — The Baldwin Hold-Down System ## Overview How a pergola column connects to its footing determines how the entire structure performs — not just structurally, but aesthetically. A column that is not perfectly plumb, not solidly anchored, or not precisely positioned will produce a pergola that looks wrong and may perform poorly under wind load. The column hold-down procedure used by Baldwin Pergolas — and now widely adopted as the industry standard — was developed by Max Baldwin through decades of hands-on installation experience. It uses two stainless steel threaded components joined by a coupler: a short anchor stud embedded in the concrete with chemical adhesive, and a longer threaded rod that runs from the coupler up through the hollow fiberglass column to a tensioned nut at the top. The result is a column connection with exceptional tension, compression, and lateral resistance that can be installed accurately on surfaces that are rarely perfectly level or flat. This page covers the complete procedure: surface preparation, adhesive anchor installation, column plumbing with fiberglass tapered shims, and final tensioning. --- ## Key Concepts - Two threaded components are joined by a coupler: a short anchor stud embedded in the footing with AT-3G adhesive, and a longer threaded rod running from the coupler up through the column to the distribution box cap plate - Simpson Strong-Tie AT-3G hybrid acrylic adhesive bonds the anchor stud to the concrete chemically, achieving structural bond strength in 45 minutes at 70°F - The AT-3G tensile strength of each anchor stud is 16,950 lbs — far exceeding any load a pergola structure will impose - Baldwin supplies fiberglass tapered shims for leveling the column base to the footing surface - The footing surface must be ground flat before installation — this is not optional - The column is plumbed before final tightening, with shims and washers managing any base irregularity - All hardware is stainless steel throughout — no galvanized or zinc-plated components anywhere in the system --- ## Why Chemical Anchors, Not Wet-Set Hardware There are two ways to anchor a structural post to concrete: set anchor hardware in wet concrete before the pour, or drill and chemically anchor after the concrete has cured. Wet-set hardware must be placed before the concrete is poured, to exact dimensions, with no ability to adjust once the concrete sets. In practice, wet-set anchor locations are almost never exactly where they need to be — the concrete contractor works from a layout drawing, not from the finished pergola components. Small errors in wet-set anchor placement become large problems during installation. Drill-and-anchor with chemical adhesive — the Baldwin method — is placed after the footing is cured, with the exact column center location marked on the finished concrete surface. The installer drills where the column needs to go, not where the co
Reference documents may contain historical pricing, earlier configurator links, or technical claims needing review. Use quote tools for current estimates and returned links for designs. If sources disagree, identify the specific conflict and refer it to Baldwin for a case-by-case decision. Do not use reference span tables as project-specific engineering approval.