Can a House Withstand 100 mph Winds?
Increasingly wild and unpredictable weather events demand that builders and designers construct safe housing that is resilient to winds of 100 miles per hour (mph). Fortunately, they can refer to building codes and standards based on research in wind engineering to enhance a home’s wind resistance.
Can a house withstand 100 mph winds? Yes, with good design and quality construction. Along with wind- and impact-resistant building components, like Fox Blocks Insulated Concrete Forms (ICFs), a wind-resistant home must include a continuous path ﹘a solid connection between the walls, the walls and roof, and the walls and foundation. A strong continuous load path manages the energy or forces of the wind, dissipating the loads and holding the roof, walls, floors, and foundation together during severe winds of over 100 mph.
Roof Design and Materials for Withstanding 100 mph Winds
A strong, properly constructed roof provides a home’s first line of defense against strong winds by transferring the heavy wind loads to the supporting walls below. The roof sheathing and the roof framing transfer the lateral loads to the home’s shear walls.
A concern with roof performance in strong wind events, is winds blowing over the roof's edge which produce a vacuum and uplifting pressures that can tear the roofing membrane or system off a house. Dangerously severe winds can also transform debris into flying missiles that can penetrate and diminish the roof's integrity, leading to complete roof and wall collapse. Therefore, the size of the roof sheathing and framing must comply with the wind forces of the region. You can find the minimum requirements for roof assemblies in Chapter 15 of the IBC, Chapter 9 of the IRC, and Chapter 7 of the IEBC.
FEMA has approved the use of standard nails in areas of wind speeds less than 100 mph. In regions of higher wind speeds, they mandate ring-shank nails. Use wood nails in the corner zone, eaves and roof areas that are prone to significant uplifts.
The roof framing follows the roof sheathing as the next element found within the load path of a house. The roof framing moves the lateral loads to the shear walls. The rafter's size of a roof’s frame must resist the roof system's weight and the forces caused by wind.
Wind-Resistant Roof Design
The roof design impacts its resistance to strong winds. Building experts suggest these three roof design tips when constructing a house that can withstand 100 mph winds:
1. Hip roofs with multiple, 30-degree slopes perform better under wind forces than less expensive gable roofs (2 slopes).
2. Use hurricane ties to create strong connections between the roof and walls.
3. Wind uplift forces impact against roof overhangs, so limit them to 20 inches.
Wind-Resistant Roofing Material
Several roofing materials work well against 100 mph winds; however, they often come with a hefty price:
Clay and slate tiles hold up to 100 mph winds. They can also last up to 100 years.
Cedar shakes can withstand wind speeds up to 245 mph, lasting up to 40 years with routine maintenance.
100%-recyclable metal roofs can resist winds between 110 and 160 mph and can last up to 50 years.
Architectural grade asphalt shingles can stand up to wind gusts up to 130 mph, while 3-tab asphalt shingles are only rated for 60 to 70 mph winds.
Following Hurricane Francese, which made landfall on September 5, 2004, on Hutchinson Island, Florida researchers at Texas Tech University and Haag Engineering Company visited the affected area to assess how wind uplifts and flying debris affected 3-tab and architectural asphalt roofing shingles. The study found damage to 13 percent of the architectural shingles, but 56 percent of the 3-tab shingles.
A Wind-Resistant Wall System - Comparing Wood-Frame, Steel-Frame, and ICF
A robust continuous path requires shear walls of significant integrity to stand up to severe winds and flying debris.
Building a Wood- or Steel-Frame Home to Resist 100 mph Winds
According to a report by FEMA, new wood-frame houses constructed according to building codes perform well structurally, in winds up to 150 mph, while a steel homes can withstand winds up to 170 mph. However, building wind-resistance homes can cost about 7 to 9 percent more than less wind-resistant structures.
Constructing a Wind-Resistant Home with ICFs
Insulated concrete forms (ICFs), like Fox Blocks, offer a third and better wall system, capable of maintaining its integrity during heavy winds of over 200 mph. A Portland Cement Association’s (PCA) study compared the structural load resistance of wood and steel framed walls to ICF walls. It confirmed that concrete walls have significantly more structural capacity and stiffness to resist the in-plane shear forces of high wind than wood- or steel-framed walls. ICF wall strength also lessens the lateral twists and damage to non-structural elements of a house, like electrical and plumbing. Utilizing ICFs for wind-resistant construction can effectively maintain a home's integrity during an intense wind event.
ICF also withstand damage from debris flying over 100 mph. A study by Texas Tech University compared the impact resistance of wind-driven debris between conventionally framed walls and ICF walls. The study found that ICF walls resist the impact while conventionally framed walls didn’t prevent the penetration of airborne debris. Insulated concrete blocks (or forms) provide the best protection from windblown debris, to a home and its occupants during 100 mph winds.
The Best Siding Material to Withstand 100 mph
Correctly installed and to code, most siding materials should remain intact during 100 mph winds. However, some products provide more impact resistance from flying debris, contributing to a more durable, long-lasting siding that protects the interior wall system.
Engineered Wood Siding: Light, flexible, and moisture-resistant. Superior impact resistance, ensuring durability and a long life span.
Steel Siding: Highly durable, performs better than vinyl and fiber cement, but can still experience denting and paint chipping under impact.
Fiber Cement Siding: Low-maintenance, resists cracking and breakage during impact, but still may dent.
Vinyl Siding: Affordable and low-maintenance, may dent and tear upon impact, making it a poor choice in severe wind-prone regions. The IBC mandates a wind-resistant rating for the vinyl siding of 110 mph for structures up to 30 feet high.
Floor Construction of a Wind-Resistant House
The floor system transfers the loads to the shear walls of the floors underneath or the foundation. Typically, floor framing consists of dimensional lumber or floor joists spanning an open area. The floor joist’s size must resist loads of the whole floor assembly along with vertical loads. The floor of a wind-resistant house ensures the loads reach the foundation and, ultimately, the ground.
Why Build a House to Withstand 100 mph Winds with Fox Block ICFs?
Fox Block ICF wall systems provide your home with superior strength during intense winds. They also resist projectile debris moving over 100 mph, better than wood- and steel-framed houses. The strength of Fox Blocks resists lateral twisting of the structure and damage to non-structural elements, and Fox Blocks ICFs will maintain their integrity against severe winds and dangerous flying debris.
Can a House Withstand 100 mph Winds? Yes!
A wind-resistant house must include a solid continuous load path that keeps the roof, walls, floors, and foundation together. The home's building components must protect against flying debris during an intense wind event. Fox Blocks ICFs are a best practice for wind-resistant walls, since Fox Blocks ICF walls will protect a home and family from strong wind and flying debris. Contact Fox Blocks today for more information on building a house to withstand 100 mph winds.