Is your home Hurricane proof
WALLS AND FOUNDATION
Preferred Construction: Houses should be single-story and constructed with concrete block as opposed to wood framing. The concrete walls should be tied down to the poured concrete slab with iron bars running inside the block.
The tie-beam is a reinforced concrete beam than runs horizontally across the top of a concrete block wall. It supports the roof and anchors the hurricane straps that are partially embedded in the concrete at the time of construction. It is usually 8 inches wide and 12 inches deep with two steel reinforcing bars at the top and bottom (ideally the tie beam should have four or more steel reinforced rods and be connected to vertical reinforcing rods going down through the hollow block walls and embedded in the footings).
Tie beams can be strengthened with steel plate strips or by increasing their thickness with wood beams. To determine if you have a tie beam: remove a piece of drywall or plaster about 12 to 14 inches deep from an inside perimeter wall, adjacent to the ceiling. If there is a reinforced concrete tie beam, it should be visible: about 12 inches deep as measured from the top of the ceiling on single-story structures. The concrete looks different from the concrete block below it. The interior walls of the home should be wood frame instead of today’s flimsier metal frame. Use plasterboard coated with metal reinforced plaster on interior walls to provide sturdiness. The air conditioning compressor should be anchored to a concrete slab with nails.
(1) Periodically check metal and wood support columns on patios for rust and wood decay.
(2) Check the anchoring of the air conditioning compressor to see if it feels loose.
(3)Check tie beam for crumbling concrete and rusted steel rods.
(4) Look for cracks in your exterior walls as well as the foundation. Cracks are caused by shifts in the ground below the house, typically caused by rotting vegetation. Cracks less than one half inch wide are common in walls and do not mean that the wall is weak (only wide cracks indicate a problem).
All cracks in the foundation should be repaired. To repair foundation: Pressure grouting company or geotechnical engineer drills hole in slab and pumps cement in to fill the gap (cost $1000 to $3000).
WINDOWS, DOORS, GARAGE DOORS SKYLIGHTS AND VENTS:
Small to medium sized windows instead of large windows, glass doors and/or bay windows are preferable. All windows should be protected by some type of shutter. Check periodically the caulking surrounding windows for cracks which can cause leaking and re-caulk as necessary.
Doors should open out – almost all South Dade doors that opened in were blown in during Andrew. Doors that open in should be protected with a hurricane panel (leave your strongest door un-shuttered). Cracked or decaying wood jambs should be replaced. All exterior doors should be preferably made of thick steel. To give your door extra strength, install a lock that slides into the frame of the door and one that slides into the floor.
Many garage doors failed during Hurricane Andrew: the hardware connecting the door to the adjacent concrete structure failed, or the rolling track bent and failed, or the doors themselves were unprotected and were penetrated by flying debris. If a garage has two separate one-car doors, 8-by-7 feet, you can board up the outside with plywood but it is not recommended for such a large opening. One double door is more difficult to cover.
Check your hardware: Make sure the door panel has the necessary stiffeners; rollers can sometimes be clamped before a hurricane, or replaced with extra-duty heavy rollers. Garage doors that feel flimsy or operate poorly should be repaired or replaced.
Brace the tracks: Unless the tracks are properly mounted the whole garage door assembly could fail by shaking loose and collapsing. They should be run from the roof trusses, not a drywall runner. The back of the track is usually secured by only one flimsy brace. Additional bracing is required to keep the door from exerting pressure on the tracks. Attach a piece of 2-by-4 to the garage wall just below the height of the track. Cut another piece that fits tightly between the wall and the track. Nail the 2-by-4 to the top of the piece on the wall and screw two screws through the track into the other side of the wood. Put at least two braces on each side of the track.
Brace the door: Vertical bracing to the middle of the garage door keeps it from being sucked off the tracks or pushed in.
Most garage doors fail because they flex too much – they bend in the middle, twist in their tracks and their wheels pop out. The middle is the weakest point of the door. This point can be strengthened by installing a brace in the middle that is screwed into a plate on the garage floor and the wall above the door.
You should have more than one brace on the inside if the door is large and a corresponding number on the outside. The outside braces are necessary because you must have strength in both directions (like a pair of storm bars on a rolling shutter).
You can make your own braces by nailing three 2- by-4’s together to make a U-shaped beam and attaching it to the floor and wall in a similar fashion as mentioned above or you can back your car up against it so that it is flush against the interior of the garage door.
This will give the door the maximum strength you can provide. Don’t add framing to the door; the door will blow off the tracks.
Install exterior shutters: This is not the same as american blinds and interior shutters. After you have shuttered the rest of your house, the garage door then becomes your weakest point. It doesn’t make any sense not to shutter it, too. Shutters offer protection from flying debris.
Most screened attic and floor vents during Andrew were blow off – they should be protected in the same manner as any window or door opening. Even the dryer vent should be closed off.
During Andrew, hurricane shutters performed well on the windward walls but many were sucked off the leeward walls. The purpose of shutters is not to seal the house (the windows do that) but to protect the windows from penetration. When a window bursts open, the wind that penetrates exerts extreme pressure on the structure including the roof. Properly installed storm shutters are essential to help keep winds out and maintain the integrity of the structure.
Once the envelope of the house is breached, the internal pressures are so high that the house actually explodes. Holes should be drilled every 8-12″ and pre-set with lead shields or tapcons (nails will not suffice). All window coverings should be installed flush to the building at least four inches over and outside the opening, not close to the edges.
To attach, use drilled holes, lead shields or tapcons, and large, deep lag bolts or tapping screws (fasteners should preferably be made of stainless steel). Make sure you can lift and install your shutters prior to hurricane season.
Hurricane shutters are manufactured of aluminum, heavy-gauge steel, reinforced PVC or Lexan. Many require reinforcing bars for maximum protection and the number of bars used should follow the manufacturer’s recommendation. Manufacturers claim the strongest shutters are metal accordion-type and the metal panels because of the corrugated or pleated surface. The lower the gauge of the steel or the thicker the aluminum, the stronger the shutter will be.
Example: .050 aluminum is stronger than .040. Steel gauge should be 20 or less. Shutters should be cleaned and the moving parts lubricated every six months. With storm panels, care should be taken when storing them to prevent damage to the clips and springs. Removable shutters and panels can be difficult to install for one person. The most important factor about storm shutters is how well they are anchored to the outside walls.
Costs vary by the type of shutter and the size of the window opening. Costs vary from $7/square foot upwards to $40/square foot for the most expensive shutters.
Aluminum Awnings are slightly rounded shutters permanently attached to the top of the window with bolts. They swing down over the window and are bolted into place at the bottom. Construction: aluminum.
Bahama Shutters/Awnings are flat louvered panels permanently attached to the top on the window with bolts. They swing down over the window and lock into place with a latch. Some models crank down from the inside. They cannot be used on sliding glass, garage or entrance doors. Construction: aluminum.
Colonial Awnings/Shutters are permanently attached to each side of the window with bolts. They swing over the window like double doors and lock into place with a reinforcement bar. Construction: aluminum.
Hurricane or Storm Panels
Roll-Down Shutters roll down via a hand crank along a track from a valance bolted across the top of the window. Construction: aluminum, foam-filled aluminum, PVC or Lexan.
Plywood Shutters: If the windows are no more than 3 feet across, 1/2″ plywood attached with screws may be sufficient to prevent interior damage most of the time, 5/8 ” plywood is preferred. To install plywood, cut 4×8 sheets of 1/2″ CDX exterior plywood slightly larger than the window or door opening and mark each sheet for location. The plywood should overlap the window or door opening by four inches. Pre-drill holes in the concrete on both the left and right sides of the window using a masonry or carbidetipped drill bit. Hammer three 1/4″ or 1/2″ machinescrew anchors or lead shields that are two inches long into the pre-drilled holes. Tighten 2″ tapping screws through the plywood and a washer until the wood is held flush against the wall. You can join pieces by nailing cross members of 2×4’s back and forth. This should be done for large windows and sliding glass doors although plywood is not recommended for such large openings. The most important factors are securing the plywood properly to the exterior wall and providing at least 4″ spacing between the glass and the plywood to provide for flexing.
PATIOS: Best bet – remove screens and doors and reinstall them after the storm. It is less expensive than replacing the screens. There is no foolproof method to minimize damage to patio screens. Leave a little play in the screens (not installing them too tight) and brace with thin pieces of wood where you expect maximum deflection.
Trees in some areas do not have very deep roots due to the high water table or they were grown in containers where the roots spiraled before planting leading to a poor root system. Also consider removing large, top heavy trees that are close to your house (black olives, ficus).
Privacy Walls constructed of concrete, if strategically placed, can be helpful in deflecting the wind force away from the building.