The PC Professional
Chapter 4
Hurricane Insurance
Hurricane season officially begins June 1 each year in many states. Across the country the media tracks hurricanes but unless an individual actually lives in a hurricane area it is hard to understand the magnitude and power they possess.
In states where hurricanes are an issue, property insurance policies may be required to cover damage caused by wind during any storm the National Hurricane Center declares to be a hurricane. Hurricanes are well known for causing damage to homes and property. They are large usually slow-moving storms that bring with them high winds and wind-driven rain that can impact a home from multiple directions if the eye of the storm passes nearby. As a result, the wind affects different homes in profoundly different ways, depending on their design, location, and neighboring structures. Hurricanes can also cause storm surges that affect coastal properties and rain-induced inland flooding.
The wind of a hurricane is extremely powerful. The wind can knock out or burst open windows and doors, rip off roof sheathing and destroy gable end walls. Over-hanging eaves and gable end rakes, extended awnings, open porches, and other features that tend to trap air beneath them are particularly susceptible to being damaged or ripped off the building.
Wind-borne debris from neighboring buildings, including shingles and tiles, can break windows and damage roof coverings and walls. Even without blowing debris, the wind can push in a garage car door, windows or house doors on the windward side of a home and move inside, increasing uplift forces on the roof. These powerful forces can literally lift the roof up off the house. Once the wind forces open a portion of the structure, wind and water is able to enter the home causing additional damage. Older, less wind resistant homes broke open regularly in high winds. As a result, much of the focus today has been on strengthening the structures and load resisting connections.
Water damage is just as much a problem as wind damage. Once the wind has opened up a structure, wind-driven rain enters, causing additional damage. Direct wind damage to structures built to high wind standards has been reduced, but it has become clear that just improving the structural integrity of homes is not enough. Wind driven water intrusion can cause catastrophic damage to walls, ceilings, and interiors of homes, which leads to major disruption of households. Water intrusion can be of particular importance to the homeowner because some insurance policies do not cover water intrusion unless it originates from damage to the roof, walls, windows or doors of the home. When wind speeds get above 60 mph, rainwater is driven against the exterior of the home with great force. Any time water builds up on the exterior wall surfaces and there is lower pressure on the inside of the house, the water can penetrate in large quantities through cracks, holes and gaps in the siding and around windows and doors. When this happens for hours at a time the resulting damage and mold can be as devastating as wind damage. Mold is particularly a problem if no electricity is available to dry out damaged homes. Water intrusion has finally been recognized as a major issue in home damage.[1]
Anyone living in a hurricane area must take steps to protect their homes and property. The most important step that can be taken is reducing the ability of hurricanes to cause damage in the first place. According to research, it is important to strengthen the exterior of the home so wind forces and debris impacts do not create large openings allowing wind-driven rain into the home. This can be done by protecting and reinforcing six critical areas:
States that routinely experience hurricane damage often create state run insurance programs. For example, in Florida the program is called the Citizens Property Insurance Corporation, insuring 1.2 million policyholders.[2] Legislatures may also create state administered reinsurance programs providing a stable and ongoing source of reimbursement to insurers for a portion of their catastrophic hurricane losses. A reinsurer insures insurance companies.
While each state will have variances, it is not unusual for them to require insurance companies issuing residential property insurance to also cover hurricane windstorm in their policies. Residential policies include both personal lines and commercial lines. Personal lines would include coverage provided by homeowner’s mobile homeowner’s, dwelling, tenant’s, condominium unit owner’s, cooperative unit owner’s, and similar policies while commercial lines would include coverage provided by condominium associations, cooperative associations, apartment buildings, and similar policies, including those covering the common elements of a homeowners’ association.
Generally, hurricane coverage is coverage for loss or damage caused by windstorm during a hurricane. It includes damage to the interior of a building or to property inside the building, caused by rain, snow, sleet, hail, sand, or dust if the direct force of the windstorm first damages the building, causing an opening through which rain, snow, sleet, hail, sand, or dust enters causing damage.
Windstorm would typically include wind, wind gusts, hail, rain, tornadoes, or cyclones caused by or resulting from a hurricane that results in direct physical loss or damage to property.
Hurricane is generally defined as a storm system that has been declared to be a hurricane by the National Weather Service’s National Hurricane Center. A hurricane includes the time period (1) beginning when the National Hurricane Center issues a hurricane watch or warning for any part of a state, (2) continuing for the time period during which the hurricane conditions exist, and (3) ending 72 hours after the National Hurricane Center terminates the last hurricane watch or warning issued for any part of the state.
Some types of property improvements provide property insurance discounts from the insurers. Protecting openings, such as windows, gable vents, or skylights, protecting exterior doors, replacing garage doors with impact-resistant garage doors, or bracing gable ends in the roofs of homes might be eligible for grants when the improvements are recommended in an inspection report.
If an improvement is made to a structure, such as strengthening openings, there are typically specific requirements if the goal is a reduction in insurance premiums. For example, if an individual chooses to protect their openings but cannot afford to do everything, he or she must complete an improvement category. This might mean protecting all windows rather than just some of them and might include gable vents. If exterior doors are chosen, all doors must be protected, including sliding glass doors. Skylights are considered a stand-alone item in many cases.
Openings include such things as windows, doors, sliding glass doors, garage doors, and any other natural opening into a home. Protecting windows and doors from windborne debris is an important part of protecting any home or structure. Besides protecting the objects inside the building, by protecting openings from wind and debris the roof is also protected. When the media shows stories of approaching hurricanes it is common to see homeowners nailing boards over their windows. This is to prevent breakage that would allow wind and rain to enter the building. Unprotected windows are especially vulnerable if:
Older homes that were built before modern high wind building codes are at risk and, due to the debris that results from them, also place newer homes at risk. When homes do not have hurricane clips or straps holding the roof structure to the walls window and door protection becomes critically important. If a large window or door is broken open on the wall facing into the wind, the overall uplift forces that are trying to lift the roof may be doubled.
Research has shown that protecting the windows and doors can raise the wind speed required to lift the roof from the home by one to two hurricane intensity categories. This means if the roof of a home would likely lift off during a Category 2 hurricane should a large window break open on the windward side of the house, by protecting openings that prevent breakage, it might take a Category 3 or possibly even a Category 4 storm to lift the roof off.
Installing shutters over windows and doors can protect them from the impacts of windborne debris and can keep wind pressures from building up in the house to the point where it significantly increases the uplift forces on the roof. Unfortunately, they may not keep the doors and windows from bursting open from wind pressure if they are weak or poorly anchored to the walls of the house.
Most windows and doors will leak at some point from a hurricane. Therefore, the key to preventing excessive damage is to minimize or manage the water intrusion. Keeping water from being driven against a home where it can build up on windows and doors is the best way to minimize water intrusion during a hurricane. Fixed glass window systems that are not operable containing impact resistant glass that is mounted into the frames with structural adhesives is another approach.
Not everything we commonly see used will prevent water intrusion. Putting masking tape, duct tape, or any other type of tape across a windowpane will not prevent water intrusion or even glass breakage. Hurricanes have extreme force behind them; tape is certainly no match for their winds.
Like tape, window films called daylight installations are unlikely to prevent damage from hurricane winds. Some homeowners have thought window film might be an alternative to other window protection systems, but this type is not. Installing such window films does nothing to keep the window attached to the frame so it provides no additional protection from winds and rain.
Another type of window film is known as safety film and does provide some protection if it meets thickness requirements (at least 4 mils in thickness). Typically, safety film products meet the same break-safe requirements as tempered safety glass, which means that the safety film should hold the glass shards together preventing a potential hazard from sharp broken glass. While this may make hurricane damage less dangerous (from broken glass) it may not prevent wind-driven rain from entering the house. Safety glass may offer a degree of protection in case of high winds if it is well anchored to the window frame using a method that has been shown to keep the film in place after the window is broken. Window film installations with proper anchorage tend to be quite expensive compared to the lesser daylight installation of adhesive placed on the windowpanes. The more expensive safety films have usually only been proven for commercial applications where the frames are more substantial than those typically found in residences. Unfortunately, when used in homes the frames may not be as substantial as they are in commercial buildings.
The best way to protect existing windows and doors from damage in hurricanes is to install tested and approved impact-resistant shutters over all windows and glass doors. They will provide protections from wind-borne objects and reduce the chances of damage caused by pressurization of the home if a window or door is broken. Insurance companies will not give a Windstorm Insurance Discount unless an approved product protects all openings.
All windowpanes should be debris resistant. These are made of special glass that even though they may break or crack the glass will not fall out of the frame and let water pour into the house. They remain in place to protect the home interior. Although expensive, the extra cost is nearly always worth it. Impact rated windows can cost three times the least expensive ones that have a pressure rating needed for the location. The alternative is to install outside panels that will absorb the shock of debris when closed over the windowpanes. If outside panels are used, they should be strong enough to prevent glass breakage behind them. The easiest retrofits are those that simply cover the opening with an approved structural panel.
Many homeowners felt protected by the shutters they installed only to find them blown off following a hurricane. These shutters were not adequately fastened. Consequently, it is important to select an adequate protective system as well as providing strong permanent anchors for the system. Even window frames are not always attached to the house well enough to withstand powerful hurricane winds, especially in older homes. Most windows simply are not designed for the amount of force hurricanes represent.
Ridge vents, off ridge vents, gable end vents and soffit vents can let a lot of water into the attic, which will soak the insulation and lead to the collapse of ceilings in the home. Some have estimated that 75 percent of past hurricane damage was due to significant damage to soffit material that allowed damage to occur in other areas of affected homes. Solid soffits made of plywood or other solid panel materials seem to best protect homes.
Even when gable end vents have louvers designed to keep water out, they are not going to prevent entrance of water driven by hurricane force winds. The louvers would have to be 6 to 10 inches high to have any hope of keeping out the water and it is unlikely they would be that size.
Ridge vents are metal or plastic caps that are put over gaps at the ridge of the home’s roof to allow hot air to escape from the attic. Off-ridge vents provide a similar function but the holes for ventilation are cut in the sheathing a small distance down the roof slope from the ridge. Cooler air typically enters through the soffits and hot air exits through the ridge or off-ridge vent. The result is circulation that cools the attic, provides a route for moisture expelled from the heated roof sheathing to exit the attic, and cools the sheathing to reduce temperatures of the roof. This helps to prolong the life of the roof covering. During a hurricane ridge vents are often knocked loose or entirely out of the roof during the hurricane. This can lead to significant water intrusion.
Off-ridge vents leak during some wind directions and others break loose so that water pours in through the hole in the roof.
Homes may have holes, cracks, gaps or openings that the homeowner can easily overlook. Such things as the holes where water faucets emerge, dryer ducts, or natural settling building cracks can allow water to penetrate during a hurricane. Wind-driven water will find its way into homes through entrances that would not appear to be a hazard. Even a cable that emerges through a wall can allow water into the home. All of these areas should be sealed as much as possible. Caulks often work the most effectively and are relatively easy to use. Some areas that are wider than ¼ inch may take multiple applications.
Cracks in homes are more significant than most people would realize. A hairline crack in a stucco house only 6 inches long and 1/64th wide has the same area to let water in as a square hole over ¼ inch on a side. A stair step crack only 1/32nd inch wide in a block house that includes two vertical steps, and one horizontal run has the same area to let water in as a hole one inch on each side. A 1/16th inch wide crack between 6-inch wide siding boards has the same area to let water in as a hole nearly 5/8 inch on each side. A crack between a window frame and the house that is only 1/64th inch wide has the same area to let water in as a hole ½ inch on each side.
Hurricane winds will push water from grass yards up walls so any entrance, no matter how insignificant, will allow the entrance of water. Floor levels, therefore, should be well above the ground or sidewalk.
The roof sheathing or roof deck serves a number of critical functions. It is the base upon which the roof covering is applied. The roof covering is the home’s first line of defense against keeping hurricane winds and wind-driven rain out of the structure. Of homes that have enough damage following hurricanes to file a claim, 95 percent had some level of roof coverage damage. When there is damage to roof coverings during a hurricane the building is at risk for subsequent rainstorm damage. Mold problems often follow this type of damage.
If it is necessary to re-roof a building, the owner has a unique opportunity to make improvements that will prevent future hurricane damage. Of course, the entire old roof should be completely removed so that the new roof is made entirely of new materials. Any extra measures that are taken at this time increase the cost but, when compared to damages that might occur during future hurricanes, are certain to be worthwhile. When roofs and exteriors are improved during non-hurricane seasons, the work is likely to be less stressful since qualified labor and wind resistant products are often in short supply following a hurricane, when need is at its highest.
There are four things to be considered when looking at exterior doors and potential hurricane damage:
Hinged doors are generally large compared to a piece of glass in a window so if a door gets broken open by wind, unless it is shuttered with a non-porous system, it will almost always result in pressurization of the interior of the home.
The strength of the door and framing is very important. If the door and framing are metal without any glass, the door will probably resist wind pressures and hurricane debris. Some kinds of solid wood doors will also provide good protection from wind pressure and debris impacts. Some doors will have stickers providing design pressure and impact ratings, but not all. Doors that have raised flat wood panels installed in a framework of solid wood may not be as strong as they appear. Unfortunately, these doors are less resistant because the raised wood panels are not always anchored well to the solid wood door and can be blown out.
Doors may not be as strong as they might appear, even when made of metal. Some metal doors have a wood framework around the edges and perhaps a foam core. While the metal may help keep windborne debris from penetrating the face of the door, it is not unusual to have the edge of the door split at the latch and the metal buckle around the latch from wind pressure or the impact of debris. Most of these doors allow enough air leakage around the edges of the shutter or through corrugations, even if they are capped, so that the door becomes fully loaded with the wind pressure from the storm. In Hurricane Charley, many homeowners had their exterior entry doors burst open even though they were shuttered.
The best way to keep the exterior entry door closed during a storm is to have a pressure rated door that is well anchored to the frame with adequate locks to handle the wind pressure. Having a door that is also impact rated will mean that the homeowner will not necessarily need to shutter the door to protect it from windborne debris.
The homeowner can shutter doors with a code-approved pressure and impact rated shutter system, but at least one door must be operable from inside the living space (not through the garage) to provide egress to the outside. This can be done by using an accordion shutter system that can be operated from both inside and outside the house. At least one door should be code approved for wind pressures appropriate for the area and debris impact tested and approved. The goal is to provide a means of escape.
Exterior entry doors (especially those that open inward) can be forced open by wind pressure or by the impact of flying debris. Doors are held to the frame around them by very little, just hinges and the door lock. Doors can get pulled out by a hurricane as well as pushed in. Adding slide latches can add strength to the lock side of the door but only if the latches are substantial, large enough, and have long enough screws to hold the latches in place. If a door has only two hinges, as they often do, it is unlikely that it will be able to withstand a hurricane wind. Dead bolts must extend far enough into the strike plate to provide sufficient strength. The strike plate is the flat metal on the doorjamb that receives the deadbolt and holds the door in the closed position. The strike plate has to be secured into the jamb very well, which is not always the case. If the screws holding the strike plate in place have split the wood of the doorjamb, it should be replaced. In fact, if any part of the door or the area it is attached to has been compromised, it should be replaced. The goal is to have enough strength in the exterior door and its frame to withstand the force of hurricane wind, flying debris, and wind-driven rain.
All doors should have at least three hinges and a security lock with a dead bolt that is ¾ inch to one inch long. The screws in the hinges need to be long enough to go through the doorframe and into the wall structure. Installing heavy duty sliding latches at the top and bottom corners of the door above and below the latch and deadbolt can provide excellent extra protection when a hurricane strikes. Doors that open inward are especially vulnerable so they must be reinforced since winds and debris can burst such doors open.
Double (French) doors have been particularly susceptible to failure from wind pressure. Homes with these doors must be given special attention in regard to strengthening and shuttering. If glass panels or wooden insets are in the double doors the least expensive option is probably to install durable shutters that can be closed over the doors during a hurricane. Even if the double doors are sold doors, the anchorage should be strengthened by adding heavy-duty barrel bolt sliding latches at the top and bottom and making sure the barrels extend into the header and the floor, not just the threshold unless it is well anchored to the floor.
Like windows, the framing around exterior doors is usually larger than the doorframe installed. This allows the frame to be shimmed so that the door is vertical, even if the framing is not quite perfect. As a result, fasteners used to hold the doorframe in place have to go through the doorframe, through the gap and into the wall framing. Fasteners can be added to improve the anchorage of the doorframe to the wall. The length of the fastener will need to be at least 3 inches. Wood screws should be #12. Nails should be 10 or 12 penny. Tapcons can be 3/16-inch diameter. Finish nails will be the least visually apparent. Counter sinking nails just a little below the surface and then filling the shallow hole with caulk will make them nearly invisible. If the individual is sure he or she is getting a good bite into the structure of the house, then space the first fastener within 6 inches of the end of the frame member, with one fastener at the top and one at the bottom of each side; then no farther apart than 16 inches. When fasteners are installed one can probably feel how well they are biting into the building. If the fasteners are loose it may be necessary to use a longer fastener. If the fasteners are just slightly infirm the wood of the house may be rotted because of previous water damage or termites or the fastener may be missing the structure. This can happen when the window on a frame house is located near the outside face of the wall. If the installer is using screws, it is important to make sure not to tighten them so much that the doorframe becomes warped.
Doors that swing out may work better at keeping out water than doors swinging in. In-swinging doors do not have the strength of their frame to keep them closed. Even so, no door (except submarine doors) can keep all water out. There will always be some water that comes in around the doors.
Sliding glass doors and patio doors present specific problems when protecting against hurricane damage. Unless the glass doors were specifically designed for high winds, they offer no resistance. When experiencing wind-driven rains, they allow the water in which may actually allow windows on the other side of the house to get blown out. Then both wind and rain have free access to the home.
Newer sliding glass doors use tempered glass, which is better than regular window glass. If it is tempered glass, a label will indicate this, or it will be etched in one of the corners. Even tempered glass doors, however, are still vulnerable to hurricane winds and rain because they can often get pushed out of their tracks and head piece or be shattered by flying debris. Few sliders have been designed to hold in place under strong winds. Probably the only effective solution is shuttering sliding glass doors in preparation of a hurricane. While this may hold the doors in place it is unlikely to keep wind-driven water out, however. Some water will still come in, although it may reduce the amount significantly. Using a non-porous shutter system will also help prevent the house from getting pressurized if a sliding glass door fails during the hurricane. It is important to know that even using a non-porous shutter system may still allow pressure to build up behind the shutter on the sliding glass door, which can cause the door to pop out or the glass to break. Additionally, the tracks of the doors are often not well attached to the walls of the house.
The door framing and installation details will make the difference between protecting the home as much as possible and experiencing severe hurricane damage. Of course, all doors must be installed according to manufacturer’s installation requirements, using tested hardware.
Each home has its own features and vulnerabilities. As a result, it is difficult to say that any one upgrade fits all homes. This is especially true of structural retrofits. For those who decide to begin major changes to their exterior walls, most professionals recommend obtaining the services of an architect or structural engineer specializing in hurricane damage.
All parts of a structure work together to make it wind and water-resistant, so it is nearly impossible to focus only on a single element of a home. With structural retrofits it is smart to work from the top of the walls downward. Each retrofit will engage more of the weight of the house. By starting at the top of the wall, each retrofit introduced will make a difference, increasing the ability of the home to survive a hurricane.
Since it would be easy (although expensive) to virtually rebuild the entire house, most people concentrate on the practical in terms of cost and time. Perhaps the least expensive and easiest guide to follow is the Standard Building Code Congress guide SSTD 10 that was published in 1999. The download can be from the International Code Council website:
https://shop.iccsafe.org/sstd-10-99-hurricane-resistant-construction-standard-pdf-download.html
In most cases, the easiest and least intrusive structural retrofit is strengthening a gable end wall. If the house has a gable end, click on Gable End Walls to look at some of the options available on the code website.
Roof damage is the greatest risk faced by homeowners when a hurricane strikes. Wind resistant homes are not only built to hold up their roofs but also to hold the roofs down. The weight of most roofs is around 7 to 10 pounds per square foot, but the uplift pressures averaged over the roof in a strong hurricane can be four to five times that amount. When wind enters the structure and pushes up on the roof it can even be 10 to 15 times higher than the weight. The uplift at the wall connections is magnified by the size of the roof because the pressures act on every square foot of the roof. If the trusses or rafters were spaced every two feet, each connection of the rafter or truss to the wall would have to be able to hold down with a force of 1200 pounds. The Hurricane Retrofit Guide likens it to taking a building, turning it upside down, and shaking it up and down.
If metal straps or rods connecting the roof to the columns and the columns to the foundations exist the homeowner must determine what type they are. The small straps are generally able to carry about 400 pounds each; the larger straps 800 to 900 pounds each. The threaded rods carry several thousand pounds if they are adequately anchored. If it is necessary to strengthen the connections, the size of the slab or foundation must be checked to determine where the column can be anchored.
Hurricane straps are used to anchor the roof trusses or rafters to the tops of the walls. Recent storms have shown that roofs anchored using modern wind resistant connections have not failed. Even so, it is not enough to just connect the roof to the tops of the walls; the uplift loads have to be carried far enough down into the house so that the weight of the house (all the way down to the floors) becomes greater than the uplift forces caused by the wind. This is called developing a continuous load path.
Surviving hurricane damage is best achieved through proper planning. Often proper planning means acquiring education on the steps needed to protect one’s property and structures. Many states have websites that offer suggestions.
End of Chapter 4