THE PROBLEM
Designing structures that the average home buyer can afford
that is also hurricane resistant is the problem. Hurricanes
are measured by the Saffir-Simpson scale, which was
developed in 1969. According to the National Hurricane
Center, a Category Two hurricane has winds of 90 to 110
mph. Winds at this speed causes minimal damage to
structures, trees and shrubs. A Category Three hurricane
has winds of 111 to 130 mph. Winds at this speed will
cause structural damage to small commercial structures,
residences, utility buildings, and severe damage to trees
and shrubs. Structures such as mobile homes would be
completely destroyed. A Category Four hurricane has winds
of 131 to 155 mph. Winds at this speed will cause severe
glass curtainwall failure on low rise and high rise office
buildings, complete roof failure on small commercial
structures, office buildings and residences. It will also
cause major damage to any building's windows and doors.
Signage, trees and shrubs are completely displaced and
smaller
secondary structures completely destroyed.
FEMA and PATH Recommendations
Due to the damage caused by recent hurricanes like
Katrina, Rita and Wilma, the Federal Emergency
Management Agency (FEMA) and the Partnership for
Advancing Technology in Housing (PATH) have
recommended changes to new home building materials
and construction methodology. The key is to make new
homes more wind and flood resistant. FEMA defines
flood resistant materials as any building material
capable of withstanding direct and prolonged contact with
flood waters for 72 hours or more without sustaining
significant damage that requires only low cost cosmetic
repair. FEMA recommends floor materials to be clay or
concrete tiles. Walls and ceiling materials should be brick,
vinyl siding, cement board, fiber cement, pressure treated
plywood and lumber, metal studs, water resistant drywall,
fiber reinforced gypsum or glass. All drywall products
should have a non-paper skin.
PATH recommends providing moderately pitched roofs,
below 6/12 and greater than 4/12, because mid-range roof
slopes withstand hurricane winds better than steep roofs.
"Hip" roofs are encouraged to be used instead of Gable
end roofs because they are more wind resistant than
Gables and will shed water away from the roof.
Pre-engineered trusses allow for faster installation and
should be used in lieu of trusses built on site.
Other roof recommendations include anchoring hurricane
straps, used to tie down trusses, to load bearing walls,
using baffled ridge and soffit vents, extend fascia board to
terminate below underside of soffit, use minimum 5/8
inch plywood roof deck anchored with 8d shank nails at
6 inches on center, use 30 lbs continuous peel and stick
felt membrane underlayment and rated install wind and
impact resistant asphalt shingles.
