How to Secure Gazebos, Pavilions, and Pergolas in a High-Wind Event

03/24/2023

Why do they matter?

Many homes have accessory structures such as sheds, gazebos, pavilions, pergolas, and attached structures, including open carports. An unsecured accessory structure can be loosened, lifted, and moved by high winds during hurricanes, severe storms, or tornadoes, causing damage and creating dangerous conditions.
Engineering analysis after high-wind events often finds that damage begins when an attached or accessory structure fails, leading to even more significant damage to the home. For example, carports with poor connections to the house can be lifted by high winds and compromise the home’s roof. Insufficiently anchored structures such as sheds can break apart and become windborne debris that cracks windows and allows wind inside the house. Making sure these structures stay in place is critical to keep you safe and help prevent damage to the structure and your home.

What do I need to know?

Securing gazebos, pergolas, sheds, or other accessory structures against high wind requires several steps:

1. Proper foundation: The structure should have a sound foundation, such as concrete footings, to ensure it is firmly anchored to the ground. If the structure rests on columns, they should be securely connected to the foundation to resist wind uplift and damage.
2. Strong anchoring: The structure should be anchored to the foundation using strong bolts or anchors designed to withstand high winds. This can include anchor straps, earth anchors, or auger anchors.
   a. Carports and other attached structures, such as swimming pool screen enclosures, must be securely anchored to a foundation and attached to the main structure.
   b. All accessory items require some form of anchorage, regardless of size. Even a small playhouse can detach and become windborne debris in extreme wind events.
   c. Generally, if an object cannot be moved indoors, you should anchor it to the ground.
3. Reinforced construction: The accessory structure should be strengthened to withstand high winds. This could involve using thicker or stronger materials, adding cross-bracing or additional framing, or using hurricane straps or truss screws to secure the roof to the walls.
4. Regular maintenance: Regular maintenance is essential to ensure that the structure remains in good condition, so be sure to repair any damage or wear and tear promptly. This can include replacing damaged or missing components, tightening bolts or anchors, and trimming trees or other vegetation that could fall on the structure during a storm.
5. Remove loose objects: Any loose objects, such as furniture, planters, or decorations, should be removed from the structure and stored inside during high winds.
6. Stay up-to-date: Stay up-to-date with weather forecasts and warnings in your area. If a severe storm is expected, taking additional precautions, such as removing the roof or dismantling the structure until the storm passes, may be necessary.

Where do I start?

• Consult a licensed contractor or engineer in your area to have them determine if the anchorage and connections on your accessory or attached structures are sufficient to resist high-wind events.

More Resources:

FLASH. Resilient Design Guide: High Wind Wood Frame Construction Edition
FLASH. Resilient Design Guide: Concrete Construction Edition