A ToolBase TechNote
The purpose of this fact sheet is to provide some basic guidance for the construction of homes in coastal, hurricane-prone areas of the United Statesnamely the Gulf and Atlantic coastlines.
Numerous studies have been conducted after hurricanes to determine what types of construction perform best in coastal or hurricane-prone areas. Recent scientific studies
sponsored by the U.S. Department of Housing and Urban Development (HUD) are particularly useful in be determining relationships between housing performance, design, and
construction (see "Resources"). The following tips were derived from those studies for those constructing, remodeling, or purchasing a home in hurricane-prone areas.
Tip 1: Information Gathering
Contact the local building department and obtain pertinent information on local construction requirements. In particular, the construction requirements should differ between coastal (i.e., beach exposure) and inland homes. Certain construction requirements may vary somewhat from one locality to another, but most critical requirements in hurricane prone areas should be consistent.
Tip 2: Proximity to the Coast Determines Level and Type of Risk
Storm-flooding caused by wind-driven sea water that can wash-out foundations and crumble, is a major concern for coastal homes (i.e., on the beach or barrier islands). Therefore, it is highly recommended that these houses be placed on pilings in accordance with (1) local regulations that may be based on the National Flood Insurance Program (NFIP), (2) FEMA coastal construction manual guidelines, or (3) a design by a qualified design professional. Pilings elevate the living areas of a home above the storm surge height, typically based on an estimated 100-year flood height (including wave height).
For inland homes along the Gulf and Atlantic coastlines, wind is the major risk factor. Wind can cause structural damage, such as blown off roofs. More commonly, it causes the roofing, siding, windows, and other exterior finishes) to be damaged, allowing wind-driven rainwater to enter and damage the contents of the home. Damage may be attributed to any number of causes including the storm magnitude or rarity, minimum code requirements, construction quality, material durability (i.e., corrosion or rot), site exposure, and many other factors.
Tip 3: Consider Design Decisions That Reduce Risk to Wind Damage
The advice of an experienced local builder, design professional, or code official is recommended in determining the appropriate design decisions for any home, particularly those in hurricane-prone areas. However, many important issues may not necessarily be addressed specifically in the building code. Therefore, the following may serve as "universal" guidelines for improving a home's ability to resist wind-related damage from hurricanes. Bear in mind that trade-offs must be considered since improved performance generally means more construction cost or sacrifice of certain desirable features. Also, these tips are given with the understanding that the construction must at least meet the local building code requirements.
Consider living in a less risky environment (not an acceptable solution to those desiring a coastal or beach lifestyle).
A lower profile house is inherently less vulnerable (i.e., a one-story house is less likely to experience wind damage than a two-story house.
A gable roof home is inherently more vulnerable to wind damage than a hip roof home, although this can be overcome by design.
Very low and very steep sloped roofs generally create increased uplift and lateral wind loads, respectively, and should be avoided.
Roof sheathing installation should consider 8d (eight-penny weight) nails spaced at no more than six inches on center in roof framing members. Ring shank nails may be considered for added resistance with a relatively small increase in cost.
Install roof shingles, sidings, and other exterior finish materials with adequate fastening to prevent tear-off and water entry in at least common tropical storms or moderate hurricanes (i.e., Category 1 and 2). For roof shingles this may simply involve the use of six nails per shingle rather than four.
Ensure that adequate connections, brackets, anchors, or tie-straps are provided to transmit wind uplift loads adequately to the foundation. The need for and amount of special connectors will vary by house configuration, site exposure, etc.
For homes in particularly severe hurricane environments (e.g., South Florida and the barrier islands), protection of window and door glazing may be required by the local
building code. In most hurricane-prone areas, however, wind-borne debris protection is considered to be the responsibility of the homeowner. Wind-borne debris protection may be provided by impact resistant glazing, permanent shutters, or temporary shutters at costs of up to several thousand dollars. As a less costly alternative, plywood panels can be used to protect windows, provided screws of adequate size and capacity are used to penetrate into the framing and resist wind suction forces. Installation of plywood panels can be a demanding task, particularly for upper-story windows.
For more information on wind resistant design and construction the following reference is recommended. Local building regulations related to home construction in hurricane-prone areas should also be obtained.
Residential Structural Design Guide: 2000 Edition,
U.S. Department of Housing and Urban Development, Washington, DC
NAHB Research Center
Upper Marlboro, MD