Wind Mitigation

Wind Mitigation

Wind mitigation techniques Wind mitigation is the implementation of certain building techniques in order  to limit damage caused by intense wind.

A Few Facts About Windstorms and Wind Insurance

  • In 2006, Citizens Insurance, one of the largest property insurers in  Florida, requested a 45% rate increase for wind insurance. Other insurers  took similar actions.


  • In Florida, the portion of a homeowner’s premium covering  wind damage can be up to 70% of the total, depending on  location.


  • Wind mitigation benefits homeowners, private insurers, and all levels of  government.


Incentives for Wind Mitigation

  • In Florida, homeowners can benefit from reduced insurance premiums. The  Gulf Coast states, which are most prone to windstorm damage from hurricanes,  have each considered mandating incentives to mitigate damage due to wind.  Mississippi and Texas currently do not have such legislation, although  Florida has been successful. Following Hurricane Andrew, Florida passed a law  requiring insurance companies to offer their customers discounts and  credits for existing building features and home improvements that reduce  damage and loss from wind. In order to qualify for this discount, homes  must undergo a certified home wind inspection. However, many Floridians do  not know of this law.
  • Those with windstorm insurance can avoid a costly deductible. Deductibles  for homes in hurricane-prone areas can exceed $20,000, meaning that mild to  moderate wind damage might not be covered by insurance at all. If proper wind  mitigation techniques have been used, these expenses can be avoided  altogether.
  • Wind mitigation helps protect the home from damage. Even if a home is  insured, it is always costly when a house is damaged, both  for the homeowner and the insurer. Repairs can take months, especially  during material shortages that follow massive destruction to entire communities,  as was the case after Hurricane Katrina struck Louisiana.
  • Lenders in Florida require homeowners to carry windstorm insurance in  order to be approved for a mortgage. Insurers may not provide  windstorm insurance to homes that are vulnerable to wind damage.

Checklist for Wind Mitigation Techniques:

  • garage doors:  These commonly fail during windstorms due to:
    • inadequate door-track strength and mounting systems; and
    • flimsy metal panels.

The following features can protect a garage door from wind damage:

    • no windows;
    • the tracks for the door that have six to nine mounting  brackets, or continuous mounting;
    • track brackets that are securely attached to the wall; and
    • horizontal and/or vertical reinforcementAreas of high and low pressure can cause roof failure on all panels.
  • opening protection:  Glass doors and  windows  should  be replaced with impact-resistant glass. They should be structurally attached to  the building in order to prevent the entire window from popping out of its  frame. Sliding glass doors are especially vulnerable to flying debris due to  their large expanse. Once an opening is created during a windstorm, the pressure  within the house can rise high enough to cause the roof to fail in areas of low  pressure. The picture to the right demonstrates how these areas of low pressure  can form.


  • roof covering: There are many kinds of  roof covering materials, and some resist wind damage better than others. The  most common roof covering materials in Florida are composition shingles and  tiles. A key factor in roof covering performance is the method of attachment of  the roof covering material to the roof deck. Nails, not staples, should be used  to fasten these materials.


  • roof shape:  “Roof shape” refers to the geometry of the roof,  rather than the type of roof covering. The end-walls of gable roofs extend  vertically to the sloping roofline. These gable end-walls, if not properly built  or braced, have been known to fail outward due to the negative suctions on  the wall. Additionally, field testing has shown that hip roofs receive up to 40%  less pressure from wind than gable roofs.


  • roof deck attachment:  According to insurance claim data, a house  becomes a major loss once the roof deck fails, even partially. The most common  roof deck types are plywood and OSB. The most important feature of the roof deck  by far is the attachment to the framing compared to the deck’s thickness.  The following building techniques can help prevent wind damage:
    • roof coverings using shingles that meet the FBC  requirements;           
    • roof decks that have been installed with large nails and close  spacing;
    • hurricane clips/straps that hold the roof structure to the walls;  and
    • protection of windows and glass doors with impact-resistant glazing or other  protection systems.
  • roof-to-wall connections:  This connection is a critical safeguard that  keeps the roof attached to the building and acts to transfer the uplift loads  into the vertical walls. This connection is crucial to the performance of the  building due to the large negative pressures acting on the roof. Proper  installation is essential to connector performance.


  • secondary water resistance: This is a layer of protection that shields  the home in the event that the roof covering fails. It will reduce leakage  if the shingles are blown off. A secondary water barrier is relatively rare in  homes. The two most common types are:
    • self-adhering modified bitumen underlayment, which is applied to the  exterior of all joints; and
    • foam seal, which is sprayed onto the underside of the  decking.
From  Wind Mitigation – Int’l Association of Certified Home Inspectors (InterNACHI)
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