courtesy
of National
Hurricane Center
ROOF
RETROFITTING
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.
The
above information is taken from IBHS's
instructive pamphlet, "Is Your Home Protected
from Hurricane Disaster? -A Homeowner's Guide to
Retrofit."
