If you are in Palm Beach County, you know you are in a Wind-Borne Debris Region (W-BDR) and your property must meet the "large missile impact" rating set by the State. If you are in Broward or Miami-Dade, you know you are in a High Velocity Hurricane Zone (HVHZ.) Current building codes demand that new construction and renovated properties must meet both county and state building codes. Even if your property is older and you do not intend any major renovations that require permitting, it still pays you to understand the importance of replacing an older garage door with one which will protect the building and its contents if a named storm or hurricane makes landfall.
The Importance of a Quality Garage Door
Your garage door is one of the most vulnerable parts of your home. Garage doors are vulnerable to buckling, twisting or pulling away from the wall during high winds and to being damaged by flying debris. When a garage door fails in a storm, pressures in the building change, and that can lead to other doors and windows failing and to roofs lifting away from the structure or being destroyed. It is worth remembering that of the approximately 163,000 homes that were destroyed or damaged in Hurricane Andrew back in 1992, most of the damage began with garage doors failing.
How Do Garage Doors Fail?
- They are destroyed by flying debris.
- The door is blown inwards, twist or buckle and are pushed away from their tracks. (Known as positive pressure)
- The garage door is sucked outwards, twist or buckle and are pulled away from their tracks. (Known as negative pressure)
Once the damage begins, it usually gets worse with the result that anything in the property – both people and possessions – also suffer damage. The pressure-changes in the building result in windows and doors being smashed and the roof lifting which can then lead to total destruction.
What Are Impact Resistant Garage Doors?
Hurricane-rated doors (aka impact-resistant and wind-resistant) are designed, built, and installed to standards which enable them to maintain their integrity in winds of up to 200 mph (above Category 5 hurricane strength.)
Such winds blow debris into doors. Hurricane-rated doors can withstand powerful impacts. They are tested by having a piece of two-by-four wood blasted out of a pressure cannon. The door is struck three times after which it must not have any holes in it greater than three feet and must still remain operable.
What are the Standards?
The standards are based on Wind Code and they differ depending on several things. The six factors listed below are used to determine which rating the door must have.
- Where the property is located.
- The average roof height of the building.
- The length and width of the property from corner to corner.
- The garage door size (single or double door for example.)
- The distance from the garage door jamb to the building's corner.
- The building's orientation (north, south, east or west-facing.)
Do I Live in an Exposure Zone?
The property location also determines which wind-rating meets current building code. Palm Beach, Broward, and Miami-Dade fall into "Exposure B" "C" or "Exposure D" zones. To keep it simple, most Broward and Miami-Dade residential buildings require a garage door rated between W5 and W8.
- Exposure B covers all urban and suburban areas with "numerous closely spaced obstructions."
- Exposure C covers "open terrain with scattered constructions" and affects most of Broward and Miami-Dade.
- Exposure D covers any building "located within 600 feet of oceanfront or other large body of water measuring at least 5000 feet across."
How Resistance is Achieved
Older Garage Doors
An older door can be improved with add-ons. Removable vertical posts secured to the garage floor and ceiling are linked by metal attachments to the door. The posts and attachments resist positive and negative wind pressure. They must be set in place before a storm, and then removed afterwards to enable the door to be operated. If the door has windows, these must be protected by permanently fitting high impact-resistant material behind the glass.
If the basic door material cannot withstand wind borne debris such as tree branches or, say, roof tiles or plywood from a neighboring damaged property, and it smashes holes in the door, then storm damage can still wreak havoc.
Some property owners install hurricane panels in front of the door as with other doors and windows. Panels help protect weak garage door construction material against wind borne debris.
New, High Impact Garage Doors
Storm-ready doors are designed and manufactured to current code. They are also designed to meet aesthetic standards. Many homes are prestigious properties and also in subdivisions governed by deed restrictions which often set minimum standards for curb appeal.
- Multiple material layers. As well as basic construction strength they have multiple layers of steel, aluminum, insulation, and may have a wood or other attractive façade. The multiple layering maximizes door strength.
- Heavy-gauge track. This standard of track maintains structural integrity and resists both positive and negative (blow and suck) wind pressure. Doors that do not twist, buckle or lift in high winds are critical to property safety.
- Steel rod reinforcers. Installed on the interior of the garage, these reinforcing rods add to the door's strength. Most people in hurricane zones link wind speed to damage. This is, of course, a major factor but so is storm surge. A lower category hurricane can, depending on how slowly it moves across the water, create a high storm surge. Storm-driven wave-water pressure can have a huge damaging impact so the more resistant the door the better.
- Upgraded springs, track and rollers. Murphy's law holds true for garage doors as well as NASA space modules – anything that can go wrong will go wrong. Installing a resistant garage door means making sure all the little things meet standard. Installing a new door onto an old track or reusing the original rollers weakens the overall structure and safety of the product.
If you are building a new home or renovating an existing one and you want to find the perfect garage door, get in touch today; our garage door specialists will help you find a solution that matches your design and your budget.
Call us at (561) 777-6812 to ask how we can help.