How to Strengthen a Structure Against Wind Loads

Strengthen your house against wind loads during building if possible.

The most common damage done to homes comes from wind because wind puts pressure on walls, roofs, and foundations. In areas with high winds, tornadoes or hurricanes, it is important to build or reinforce homes against wind loads. Although the process is easier to accomplish when the house is being built, you can retrofit a home with wind-protection measures. The goal is to identify any weak spots in the structure of the home and strengthen those weaknesses to prevent wind damage. Windows, garages, roofs and doors are common failing points in a house.

Things You'll Need

• Drill
• 2x4 or 2x8 pieces of wood
• Hurricane straps or corrosion resistant metal strips
• 5/8 inch anchor bolts 15 inches long
• Caulking
• 3 inch screws or nails
• Shutters
• Garage retrofit kit, optional
• Plywood or commercial shutters or impact resistant glass

Instructions

1. Build your foundation with cast-in-place concrete walls with metal reinforcements instead of block construction to improve wind load if your home is not yet built. Check the foundation of any house that is already built. The foundation should be at least concrete-filled blocks on a continuous beam.

2. Anchor the walls to the foundation using hurricane straps or corrosion resistant metal straps. Place the straps no more than six feet apart. Drill into the concrete foundation of the house and secure the strap using 5/8 inch anchor bolts that are at least 15 inches long. Set the strap along the bottom of the framing on the house and secure it with screws or nails. Secure the bottom plate, the bottom of the framing and the studs to the foundation. This protects against the house lifting or shifting during high winds.

3. Add hurricane straps from the tops of the walls to the roofing. Secure the straps to the roof rafters and the exterior sill plate, the top of the framing and wall studs, placing them no further than six feet apart.

4. Brace gabled roofs using 2x4 or 2x6 lumber. Use the lumber to tie several rafters together, going against the rafters. Start in the attic at the very last rafter and screw the lumber into the rafters. Continue to place the lumber supports throughout the roof rafters to secure all the rafters together. Support both the floor rafters of the attic and the ceiling rafters of the attic. You will see boards running parallel on both the floor and ceiling all the way through the attic if this is done right. See the photo in resource 1 for a visual of what your attic should look like.

5. Secure the bottom of the gable or end wall to the ceiling joist. The ceiling joist is the framing inside the roof. Add additional support to the gable end wall by strengthening the studs. Install additional studs to the end wall next to the original studs and tie them into the top rafters inside the attic.

6. Install storm shutters over all external sliding or glass doors and windows or replace all windows with impact resistant glass. Shutters can be made from plywood or purchased already made. Impact resistant glass does not need shutter protection, but they are more expensive. Secure the shutters to the house not the window frame.

7. Caulk every seam or connection on the outside of your house. Caulk around windows and doors, where walls meet, under siding and at the roof line. Caulk anywhere there is a seam of any kind.

8. Secure your garage. Purchase a commercial retrofit kit or retrofit your garage yourself. Install 2x4 or 2x6 boards across the garage door. Place at least one board on each door panel horizontally. Make sure the boards reach from one end of the door to the other. Mount the boards on the inside of the garage door so they do not impede the function of the door.

9. Trim trees and remove all loose objects from your yard. Flying objects cause a lot of damage to homes during high winds and putting away objects and trimming trees reduces the amount of debris blowing around and hitting your home.

Tips & Warnings

• Check with your local building inspector or code officials for any special regulations that may be in place before reinforcing a house that has already been built.

References

• Montana State University Extension: Strengthening House Structures to Protect Against Shifts From Flood or Wind Forces
• LSU Ag Center: How Can I Strengthen My Home Against Wind
• Dwell Green: Building Structure

Resources

• Disaster Safety: High Winds