How holdown hardware and continuous straps create an unbroken chain from your roof to the earth. The heavy-duty connections that hold everything down in Broward County hurricanes!
Heavy-duty L-shaped brackets that bolt to the foundation and connect to wall studs. Capacities from 3,000 to 14,000+ lbs. The workhorse of high-wind construction, required at shear wall ends and building corners in Broward County.
Long metal straps that wrap from the foundation anchor up and over the wall framing. Provide direct tension connection without the bulk of holdown brackets. Often used where access is tight or loads are moderate.
Continuous threaded rods that run from foundation to roof through multiple stories. Ultimate load path continuity for the highest wind loads. Required for multi-story buildings in extreme wind zones.
Purpose-built anchors cast into the concrete with straps extending upward. No post-installed anchor bolt needed. Provides maximum embedment capacity and simplifies framing installation.
Standard 1/2-inch anchor bolts spaced 6 feet apart provide a baseline connection, but they cannot resist the concentrated uplift forces at building corners and shear wall ends. Hurricane winds create enormous suction on roofs, and this force funnels through the wall framing to specific points. A single corner might see 5,000+ pounds of uplift - far beyond what a standard anchor can handle.
Foundation tie-downs are one link in the continuous load path that transfers hurricane forces from the roof to the ground. The chain includes:
If any link fails, the entire system fails. Foundation tie-downs are the critical final link before the concrete.
Foundation tie-down installation requires precision. The anchor bolt must be positioned exactly where the holdown will attach, which requires coordination between concrete and framing trades. Common mistakes include:
Foundation tie-downs are hardware systems that connect your wall framing directly to the concrete foundation to resist hurricane uplift forces. They typically consist of a metal holdown bracket bolted to the foundation with an anchor bolt, and a strap or rod that connects to the wall studs. This creates a continuous tension path that prevents wind from lifting the walls off the slab.
Anchor bolts connect the sill plate (bottom of wall) to concrete and resist moderate uplift loads. Holdowns are heavy-duty connectors that bolt to the foundation and attach to wall studs with straps or rods, providing much higher uplift capacity. In Broward County's high-wind zone, holdowns at wall corners and shear wall ends supplement standard anchor bolts to handle concentrated uplift forces that can exceed 5,000 pounds.
Foundation tie-downs are required at all exterior wall corners, at ends of braced wall panels (shear walls), on each side of large openings like garage doors, and at intermediate points along long walls as specified by the engineer. The structural plans show exact locations and specify the required uplift capacity at each point based on the building geometry and 180 mph design wind speed.
Foundation tie-down capacity varies by product. Standard holdowns like the Simpson HDU series range from 3,000 to 14,000+ pounds of allowable uplift. For Broward County hurricane loads, engineers typically specify holdowns in the 4,000-8,000 pound range at wall corners and shear wall ends. The foundation anchorage (bolt embedment) must also be designed to develop the full holdown capacity.
WindLoad.co provides precise holdown specifications for Broward County hurricane loads. Get the uplift capacities your framing contractor needs!
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