Whether it happens while you’re setting up your shed’s roof, reroofing your house, or moving to a tropical area, you’re bound to come across hurricane ties at some point.
Essential in areas that suffer from natural disasters such as hurricanes, roof and rafter hurricane ties are a must-have for those who want to protect their home. In some cases, these ties are mandated by the State.
If you’re wondering what these are and why they’re so important, you’re in the right place for an answer.
This article will offer insight into what hurricane ties are, the different types, and why they are so important. It will also explain how to select the best kind of hurricane ties for your building and how to install them.
What Are Hurricane Ties?
Roof and rafter hurricane ties, also called hurricane straps or strips, are galvanized or low-carbon steel connectors used to strengthen wood and metal-framed roofs. They make buildings more resistant to the effects of high winds, especially in areas prone to natural disasters.
Hurricane ties are special connectors used in building houses. They are used to strengthen various roof types’ frames and firmly connect the roof to the rest of the building. Hurricane ties are most commonly added in the construction phase of the roof.
Ties help ensure that the roof’s weight is evenly distributed so that in extreme wind, it remains firm without lifting off.
The ties are used with nails, bolts, or screws to improve the structural integrity of roof work. The weight transfer in a building is only as strong as its weakest link, so hurricane ties provide stability at the joints in roof purlin plates, rafters, wall plates, and floor plates.
In wooden roofs, they also prevent degradation and decay of the timber that could lead to structural failure of the building.
Why Are Hurricane Ties So Important?
Hurricane ties are crucial because they create additional protection for the frame of a building. In a natural disaster, the roof is the structure’s first line of defense. As with doors and windows, roofs are very vulnerable to wind damage.
When a roof gets blown off during a storm, the effect is disastrous because the rest of the building is left without protection from the destructive high winds and heavy rains.
Due to this, the chance that a building will get through a hurricane with minimal damage and hold up well after the storm largely depends on its roof’s strength.
Hurricane winds can have speeds as high as 74 to 190 mph (119 to 306 kph). These wind speeds are so high that a roof without extra reinforcement cannot withstand the air pressure. This is why the worst hurricane damage usually results in roof failure.
In worse cases, strong uplift winds could even remove the roofs entirely and blow them in the downward direction of the wind. The removed tops can be propelled at speeds so high that they hit buildings in their path and damage property.
According to a roofing study reported by Treasure Coast Newspapers, an adequately reinforced and maintained roof can last 50-70% longer in a storm than an unprotected roof. That’s how much of an edge hurricane straps can offer in a hurricane.
Hurricane ties have been tested and proven to secure roofs even in adverse conditions. They provide high resistance to the immense upward and lateral air pressures of a storm.
Ties can be lifesaving additions to reinforced buildings and all other surrounding buildings. They are essential in tropical regions particularly prone to natural disasters.
How Hurricane Ties Work
The roof joist is a wooden structural framework installed perpendicular to the building beams to transfer weight from the roofing to the floor. A hurricane tie works by connecting the joists to these support beams to create a continuous load path.
The load distribution goes from the roof to the top then bottom of the wall, and finally ends in the foundation. This system gives the roof greater resistance against the upward wind force that could lift it off or the lateral force that could damage it in a hurricane.
Hurricane ties are used to connect the wood and metal members of the walls to the rafters, ridges, beams, and purlins in the roof.
How To Select Hurricane Ties
Different brands produce hurricane ties, and each manufacturer has a vast catalog of straps in different shapes and dimensions. Yet, despite the difference in these types, they all function using a variation of the same basic principle of continuous weight distribution.
However, not just any strap can be suitable for your building. Selecting one for your building could be challenging with hundreds of models available.
Here’s a checklist you can tick off to choose the appropriate model for your building:
Determine the Roof’s Weight Load
Hurricane ties have different specifications, and one of the most critical ones is the weight capacity. Choosing a tie that is designed to hold less load than the actual weight of your roof could mean terrible results in a storm.
To calculate the roof load, you have to figure out the total input of several factors.
The dead load is the weight contributed by the rooftop itself and any other accessory structures attached to it. The live load includes additional weight like the snow anticipated to fall on the roof every season.
Apart from these, the uplift effect of high wind is one of the essential loads to consider. In an area prone to hurricane storms, the uplift load is much higher than usual, and it has to be factored into the roof’s weight capacity calculations.
A hurricane tie intended to resist lateral load cannot work at maximum capacity against uplift load. The lateral demand also has to be considered in determining the weight load.
When you or your roofing contractor reaches a specific figure for all of these variables, you could also consider the purpose of the building, cost, and risk tolerance.
Calculating the combined load of all of these factors is best done by a professional, but you could use a more straightforward method to reach an estimate. When choosing your ties, be careful to only select those with a weight capacity equal to or greater than the resultant load value.
Figure Out the Dimensions’ Specifications
Hurricane ties come in different shapes and dimensions. It’s essential to choose one that will suit the joint it’ll be used for as well as possible. If the roof’s trusses or rafters will fit into the strap, you’ll need to measure the width of the beams to ensure that they can fit into the opening.
The rafter dimension isn’t limited to the width—the height matters as well. The height of the woodwork used as the bottom chord has to match the tie used for the nail holes to fit in properly.
Builders can usually work around this height mismatch, but the maneuvers often lead to a wrong installation. If multiple ties are wrongly installed, they will offer less reinforcement and overall holding capacity to the roof.
Check the Alignment of the Roof and Wall Framing
While creating a continuous weight channel, the alignment of the frames for the roof with those for the wall will determine the type and number of ties needed.
For properly-aligned frames, one strap will usually suffice. However, if they are out of place, you might need a different type of tie or multiple ties to attach both frames firmly.
Choose the Nail Fasteners for the Hurricane Straps
The instructions for any ties you choose will include recommendations for the type of nail fasteners to use. To maximize the reinforcement of the ties, you should follow those instructions closely and use the exact length and diameter of the specified nails.
The finish for the nails should also be of the same material as the hurricane ties. This need for consistency is because when two different metals are in contact, one can cause the other to rust through galvanic corrosion.
The corrosion can be especially bad when the metals get wet by an electrically-conducting liquid like water from rain or melting snow, especially in areas close to saltwater.
Confirm Your Insurance Provisions
If your building has wind mitigation insurance, you may also have to factor the insurance provisions into your decision. Depending on your provider, installing hurricane straps can help you save 20 to 50% on your insurance premium.
The discount varies, but your insurance provider might offer a greater discount for using a specific type of tie or a minimum number of nail fasteners.
Check Out Your State Building Codes
Hurricane-threatened states like Florida and Louisiana and certain coastal and tropical areas have local building codes. These jurisdiction requirements usually offer specific instructions for installing hurricane ties and roof retrofitting.
You should check with your local building department to confirm your choice of hurricane straps.
Can You Install Hurricane Ties Yourself?
It is possible to install hurricane ties yourself. However, it is a pretty complicated process, so if you don’t have much technical building knowledge, you should be prepared to do a lot of research.
The process takes quite a long time, and you must be very focused.
In a hurricane-prone area, one nail in the hurricane tie could be the difference between safety and danger. Therefore, it becomes even more critical that roof and rafters ties are correctly installed in these areas.
According to the US Federal Emergency Management Agency (FEMA), installing hurricane ties properly, especially on an existing roof, can be difficult.
It’s safest to hire a contractor to get it done during an ongoing construction project. Alternatively, you could choose to carry out the installation under the supervision of an expert.
How To Install a Hurricane Tie
The easiest time to install a hurricane tie is during the construction of a building, right after its framing. However, they could also be installed quite conveniently during a roof replacement or reroofing project.
It is also possible to install ties in a fully-completed roof, but that’s a considerably more strenuous process because the roof’s soffit will be removed.
Here is a step-by-step guide on how to install hurricane ties:
Examine the Roof
In an open roof, you will need to locate the joints between the diagonal beams and the horizontal ones in the wall. Depending on how well they align, you could need one or two straps for each joint.
Number the joints and confirm the width to get an estimate of the amount and dimension of the straps you’ll need.
To install hurricane ties in an existing roof, you have to begin by removing the roof’s soffit—the panel between the wall and the extending ends of the roof.
The material of your soffit will determine how difficult it’ll be to slide out each panel and access the inner framework of the roof. In an older roof, you may need to have a retrofit to install an entirely new roofing system over the old one.
Choose Where To Install Your Ties
Rafter ties can be installed internally or externally on a roof.
Many professionals often recommend an external installation unless it is impractical to retrofit the roof. In areas with severe hurricanes, you could even choose to go the extra mile and install the ties on both sides.
Fasten the Ties in Place
To attach the tie firmly, position it against the rafters and the top plate of the wall.
For a U-shaped tie, you should ensure that it properly grips the wooden bar inserted into it. Then, you can use a manual ratchet or a nail gun to install the ties within the wood using the proper nails and screws.
Safety Precautions for Installing Hurricane Ties
When installing hurricane ties yourself, ensure that you follow these safety precautions to prevent an accident:
- Do not work in extremely hot or cold weather. If the roof is wet or slippery after rain or snow, it’s not safe to work either.
- Wear the appropriate clothes. Durable pants, a comfortable shirt, protective eyewear, or sun-protection gear are essential. Most importantly, wear shoes with soft soles for proper traction.
- Clear any dirt and slippery material from your work area. Additionally, block kids and pets from coming in.
- If you’re using a portable ladder, read the instructions and follow them very carefully when setting it up. If it’s damaged, do not use it.
- Use accessories like a harness, anchor ropes, toe brackets, or toe boards to prevent falls. In the absence of these, you can keep someone at the bottom of the ladder to hold it still.
- Keep the ladder placed on a stable base, and at least three limbs – two legs and one hand or two hands and a leg – on it at all times.
Hurricanes can be disastrous, but proper reinforcement with hurricane ties is essential to give you a fighting chance.
All of these ties, no matter how different, serve the same purpose—to improve the resilience of your building, reduce the potential of damage from a storm, and make you safe enough to calmly sit it out.
- Federal Emergency Management Agency: Protecting Against Wind Damage
- Structural Engineering Blog: How to Select a Connector – Hurricane Tie
- Pacific West Roofing Company: 35 Roofing Safety Tips
- Youtube: Hurricane Straps
- Home Improvement Cents: Hurricane Roof Straps: A Homeowner’s Resource Guide
- Storm Preppers: Hurricane Strap Installation
- TCPalm: Hurricane 2019: Can your roof withstand the torture of a hurricane?
- Hunker: How to Calculate Load Bearing Capacity of a Flat Roof