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Roof
Retrofitting |
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Gabled
Roofs
Does
your home have a gabled roof? If so, the end wall of your home
takes a tremendous beating during a hurricane. If not properly
braced, it can collapse, causing significant damage. However,
gable end walls are easy to strengthen and deserve to be a high
priority on your retrofit list. Although truss bracing (shown
here) is not endorsed by IBHS, the Red Cross and others recommend
it as a retrofit for gabled roofs. To do this yourself, install
2 x 4s the length of your roof, overlapping the ends of the 2
x 4s across two trusses.
Typically, gable end trusses are directly attached to the top
of gable end walls. The bottom of the truss must be securely nailed
to the top of the wall and braced to adjacent trusses. This prevents
wind from pushing or pulling the gable end at its critical point,
where the gable truss is connected along the gable wall. Without
adequate bracing, the end wall may be destroyed during hurricane
winds.
To
secure your gable end wall, fasten eight-foot long braces to the
bottom chord of the gable truss and the adjacent trusses with
sixteen-penny (16d) nails. The braces should be perpendicular
to the truss, spaced at a maximum of four feet on center. In addition,
be sure to tie back the gable truss with at least one eight-foot
long brace, along the ridge of the roof, to several of the interior
trusses.
Shingles
Shingles
are usually not designed to resist hurricane force winds. They
come with integral locking tabs or factory-applied adhesives that
on occasion do not adhere properly to the underlying shingle because
of cold weather installation, uneven surfaces or any number of
other reasons. For increased wind resistance, have a qualified
person inspect several shingle tabs to see if the adhesive has
engaged. If not, use a quick-setting asphalt cement to bond them
together.
To
cement the shingle tabs to the underlying shingles, place two
spots of quick-setting asphalt cement about the size of a quarter
under each tab with a putty knife or caulking gun. Press the tab
into the adhesive. Be sure to cement all the tabs throughout the
roof, being careful not to bend them farther than necessary when
applying the adhesive. Replace any damaged shingles immediately.
Attach
Roof Sheathing with Adhesive
You
can also improve the uplift resistance of the roof deck from the
attic -- without removing the roof covering. This is how:
Using
a caulking gun, apply a 1/4 inch bead of wood adhesive along the
intersection of the roof deck and the roof support element (rafter
or truss chord) on both sides.
At places where you have limited access, such as where the roof
meets exterior walls, use quarter round pieces of wood approximately
two to three feet long and apply the adhesive along the two adjacent
sides of the block. The length of the quarter round pieces can
be longer or shorter to suit your installation needs.
Press the wood pieces in the intersection making sure the adhesive
has made solid contact with the sheathing and roof support elements.
According to static pressure tests, using the wood adhesive can
increase the wind uplift resistance of the plywood roof sheathing
by as much as three times the conventional method of securing
the sheathing with nails. It should be available at your local
hardware and building supply stores. Please ask your local hardware
expert if other products are available that could provide the
same strength and properties as a wood adhesive. Return
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Hurricane
Straps |
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Roof
to Top of Wall Connection
Metal
hurricane straps or clips provide the proper measure of strength
and safety for the roof-to-wall connection. The common practice
of toenailing the trusses or rafters often is not sufficient to
hold a roof in place in high winds. These clips or straps are
usually very difficult to see from the attic because of insulation.
Areas where the roof framing meets the top of stud walls are normally
covered by dry wall on the inside and by wall cladding and soffit
board on the outside. To install hurricane straps and clips, remove
the roof sheathing around the perimeter of the roof to reveal
the top of the wall. You may also need to remove the soffit and
exterior cladding to reveal the top 12 to 18 inches of the wall.
In addition, if the exterior cladding is brick veneer, you may
need to remove small sections of brick as needed.
If
your roof has trusses, make sure you tie them to the wall by either
anchoring to the top plate and then the top plate to the wall
stud, or strapping the truss directly to the wall stud. Return
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Shutters |
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One
of the best ways to protect a home from damage in wind storms is
to install impact-resistant shutters over all large windows and
glass doors. Not only do they protect doors and windows from wind-borne
objects, but they can reduce damage caused by sudden pressure changes
when a window or door is broken. Laminated window systems (plastic
bonded to glass) are another option, and are a particularly good
choice for either building a new home or adding to an old one.
The
easiest designs are those that simply cover the opening with a
structural panel such as plywood. In past hurricanes, many
homeowners upon returning have noticed their temporary plywood
shutters blown off because they were not adequately fastened.
If you have a wood-frame house, use adequate fasteners to attach
the panels over the openings when a hurricane approaches. Have
these temporary shutters stored and ready to use since building
supply stores generally sell out of these materials quickly during
a hurricane warning. If your home is made with concrete blocks,
however, you will have to install anchoring devices well in advance.
The
American Plywood Association (APA) - The Engineered Wood Association
offers a series of Hurricane Shutter Designs. Each design is available
for $1, or you can download all five designs from the APA's
Web site at no cost.
Manufactured
Shutters
If your residence has permanent shutters, evaluate their effectiveness.
Manufacturers are responsible for testing their shutters up to
the standards necessary to resist wind forces and wind-borne debris.
Some shutters are very flexible, especially those that roll up.
If
struck by a rigid piece of debris, shutters may bend and break
the window. To determine whether your shutter can resist this
impact, gently lean against it and see if it yields. You can also
inspect your shutters to see if they are properly attached to
the house and will not fly off during a storm by inspecting the
shutter connectors for obvious excessive wear or missing connectors.
Ask the shutter manufacturer for proper installation criteria.
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Securing
Entry Doors |
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Your
home has either double or single entry doors. If they are solid
wood or hollow metal they probably can resist wind pressures and
hurricane debris. However, if you are not sure whether they are
strong enough, take these precautions:
Install
head and foot bolts on the inactive door of double-entry doors.
(Shown here)
Make sure your doors have at least three hinges and a dead bolt
security lock which has a minimum one inch bolt throw length.
Since double entry doors fail when their surface bolts break at
the header trim or threshold, check the connections at both places.
Be sure the surface bolt extends into the door header and through
the threshold into the subfloor. Return
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Bracing
Garage Doors |
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Because
of their width, double-wide garage doors are more susceptible to
wind damage than single doors. Unless you have a tested hurricane-resistant
door, the wind may force it out of the roller track -- especially
if the track is light weight or some of the anchor bolts are not
in place. This occurs because the door deflects too much under excessive
wind pressure and fails.
To
secure your garage door:
Check
with your local government building official to see if there are
code requirements for garage doors in your area.
Check with your local building supplier or garage door retailer
to see if a retrofit kit is available for your garage door.
You should probably reinforce your double-wide garage door at
its weakest points. This involves installing horizontal and/or
vertical bracing onto each panel, using wood or light gauge metal
girds bolted to the door mullions. You may also need heavier hinges
and stronger end and vertical supports for your door.
If
you decide to retrofit your garage door with a kit that allows
you to operate the door after it is installed, make sure the door
is balanced by lowering it about halfway and letting go. If the
door goes up or down, the springs will need adjusting. Note: Since
the springs are dangerous, only a professional should adjust them.
If
you are unable to retrofit your garage door with a kit specifically
designed for your door, you can purchase garage door retrofit
kits to withstand hurricane winds at your local building supply
store. Also, check to see if the supplier can do the installation.
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The above
information is taken from IBHS's
instructive pamphlet, "Is Your Home Protected from Hurricane Disaster?
-A Homeowner's Guide to Retrofit."
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