Wind and Water Protection – Preparing for a Hurricane From The Red Cross
Posted by LPL Risk Management on
Recent hurricane seasons have provided painful lessons in the importance of preparing for these destructive storms. Perhaps most important is the need to protect your home sooner rather than later. This will allow you to focus on more immediate needs when a hurricane approaches, including gathering supplies and heeding evacuation orders.
The first step is to decide what level of protection you want and can afford – especially for doors and windows. Then you can permanently install any hardware that should be in place before storms start brewing. When a storm threatens, you can quickly install the protection and move on to other tasks and actions.
The highest level of protection normally available for windows is professionally produced shutters that meet the Dade County (Florida) standards for opening protection. These standards require that the shutter product be able to resist the impact of a 9-lb. 2’x4′ traveling at 34 mph without penetration of the shutter, and — if installed according to the manufacturer’s recommendations — not break the glass behind the shutter.
This level of protection can also be achieved for small- to medium-sized windows by making your shutters out of a ¼-inch polycarbonate sheet. This has the added benefit of providing a transparent shutter that will allow light in if the power goes out. If you are making and installing your own shutters, you may want to consider this for your windows that allow the most daylight into living areas.
It takes about a ¾-inch thick piece of plywood to provide close to the same protection as the Dade County-approved products, and that will make for a very heavy shutter. You can, of course, use thinner plywood, and plywood is recommended over oriented strand board (OSB) because it takes 30% thicker OSB to equal the impact resistance of plywood.
The resistance to penetration by wind-borne debris is reduced in direct proportion to the thickness of the plywood. In other words, a 3/8-inch thick plywood shutter would be only about half as effective in resisting penetration as a ¾-inch plywood shutter. IBHS recommends 5/8-inch thick plywood as a minimum unless you are having problems with handling the weight of the shutter.
Some layer of plywood will always be better than not protecting your window, as long as it remains in place. And even the thinner sheets will help resist the most common wind-borne debris such as small branches and shingles.
If you live in a community with tile roofs, it is recommended that you seriously consider shutter products that meet the Dade County standards for your windows.
In the wake of Hurricane Andrew in 1992, Miami-Dade County established stringent testing and approvals for hurricane shutters and other products used to strengthen and protect homes against hurricanes. These standards are thought to be more strict than those of some other national product-certification groups.
Installing plywood shutters
If you are going to make and install your own shutters, take the time to pre-install the anchorage hardware and prepare your shutter materials before a storm threatens. Pick out and purchase the material you want to use and cut it to the appropriate size for the type of installation you select. There are a lot of effective ways to install shutters and many more that are not.
While you can nail plywood shutters as a last resort just before a storm strikes, repeatedly putting them up and taking them down will damage the area around your windows and doors, and ultimately affect anchorage quality.
Plywood is stronger in the direction parallel to the grain. So you can take advantage of the panel’s inherent strength, place fasteners only on the sides perpendicular to the grain, or along the sides if the grain runs that way.
For installations on wood frame walls, you can order stainless steel studs that have wood threads on one end and machine threads on the other. Search under hanger bolts for the types of hardware you need. Select stainless steel anchor bolts for permanent masonry installations.
Be wise about window myths
Do not open windows during a storm. This only lets damaging wind and rain into your home.
Tape does not protect your windows from flying debris. It might keep more of the glass together when impacted, but it will not keep it in place.
Window film does not provide much gain in protection from impact of anticipated debris. Some thicker “structural” film passes the small missile test, which applies to things like gravel or similar sized objects. It does help keep glass shards together when the window breaks.
All doors should have three hinges and a dead-bolt lock with a minimum 1-inch bolt throw length. Metal or solid wood doors may withstand hurricane pressures and wind-blown debris, but if you have double entry doors (French doors), doors with glass or hollow-core doors, you may want to shutter them.
For double entry doors, add barrel bolt restraints to the inactive door to help keep them from bursting open during a storm. Make sure the bolts connect through the door header and through the threshold into the subfloor.
Because of their width, double-wide garage doors are more susceptible to wind damage than single doors. The wind may buckle the door, force it out of the roller track, or the track could be vulnerable to the pressure, especially if it is light weight or the fasteners don’t penetrate the wall deep enough. Wind coming into your home through an opening this large poses grave problems for the rest of your home – especially your roof.
Consider installing a garage door that is hurricane resistant (tested and approved for your area), or shutter the garage door opening with a wind pressure and impact rated system appropriate for your area. Be sure to check if there are any other code requirements for garage doors where you live.
Garage door retailers may have a wind retrofit kit specifically made for your door. If the manufacturer does not make a system for your door, you can purchase a generic garage door retrofit kit. There is at least one manufacturer of a vertical bracing kit that has Florida Building Code approval. However, keep in mind that these retrofit kits do not provide any additional protection from flying debris. Most doors that are not hurricane rated will not.
If you decide to reinforce your double-wide garage door, do so at its weakest points. Install horizontal and/or vertical bracing onto each panel, using wood or light gauge metal girds bolted to the door mullions (vertical member that forms a division between units of a window, door, or screen). Heavier hinges and stronger end and vertical center supports may be required.
If you do anything that adds weight to your garage door, call a professional to make sure the door is balanced. The springs will probably need adjusting. Note: Since the springs are dangerous, only a professional should adjust them.
It is important to prepare your yard before active hurricane months.
Trees and broken limbs are the leading cause of knocking down or pulling up power lines due to a storm’s powerful winds. Lose debris can fly into glass windows or rip apart screened-in porches during high winds, severely damaging you and your neighbors’ homes and putting your family and others in danger.
Prepare yards by trimming trees and bushes. Remove and properly dispose of all unused and inoperable items such as damaged lawn furniture and broken bikes and general debris. When this is done early, when a storm hits you can focus your limited time and attention on preparing your family and your home.
Additional steps to consider
Shutter and seal gable end vents to prevent wind-driven rain from entering attic space.
Use a high quality silicone caulk around outside wall openings such as clothes dryer, kitchen or bathroom vents, outdoor electrical outlets and locations where cables or pipes go through the wall. Just before a storm, close dryer and bathroom vents with duct tape (but remove it after a storm, before using the vents).
Consider cutting wall screens in pool enclosures just before the storm hits, if you are still there and your property is located near the landfall position. This may save the aluminum enclosure.