Hurricane season is upon us, and many people wonder how they can prepare their homes for a storm. The truth is that there’s no one-size-fits-all solution, but we can offer some general guidelines for hurricane-proofing your home.
Hurricane tie-down terms can be confusing. For instance, many people think toe nail connections can replace hurricane clips, but they can’t. Unfortunately, the confusion doesn’t end there—other commonly misunderstood terms include single wrap, double wrap, and hurricane clips.
This article will explain the different terms for hurricane tie-downs. If you read to the end, you’ll better understand these terms and be able to choose the right hurricane tie-down solution for your situation.
What Are Hurricane Tie Downs and Why Do You Need Them?
Hurricane tie-downs are used to secure a roof to a wall and a wall to a foundation. They are usually made of galvanized steel and come in various shapes, hence their many names. They hold your structure together when those 140 mph (225.3 kph) winds come around.
You must choose the right kind of tie-down based on the wind speed the device is rated for. You will also need to consider the size and weight of your house and the type of foundation it’s built on.
However, some states have hurricane strap codes in place.
For example, new residential houses in Florida must have hurricane straps on the roof. This mandate is because hurricanes are a frequent occurrence in the state.
So, if you live in an area prone to hurricanes, it’s good to check with your local building code office to see if there are any requirements for hurricane tie-downs.
If you want to go beyond the minimum requirement, you can always consult with a seasoned professional. It’s always a good idea to know the different types of hurricane straps so you can make an informed decision.
What Are Some Commonly Used Hurricane Tie-Down Terms?
Commonly used hurricane tie-down terms include clips, single wrap, and double wrap. They refer to different devices with different purposes, but they all fall under the hurricane tie-down umbrella.
Clips
The term clips refer to any device used to hold two pieces of metal together, including fasteners and brackets. There are many different types of clips, but they all serve the same purpose: to add a layer of strength to wood joints.
This term is usually used with others, such as ‘strap clips’ or ‘panel clips.’ However, the clips are only one part of the overall tie-down system.
Single Wrap
Single wrap refers to any tie-down system that uses an extra piece of metal extending to one more side (unlike the regular strap design). This added piece of metal makes the strap a more robust option than the non-strap version, making it a good choice for hurricane zones.
Usually, this type of system is used on roofs that are not very steep, and it helps prevent the top from sliding off the house in high winds. Most roofers use this system on homes that have shingles.
Double Wrap
Double wrap refers to any tie-down system that uses an extra piece of metal that goes under the truss on both sides. This component is called a ‘double-wrap strap.’
Tie-downs of this kind are usually used on steep roofs, and you have to put at least three nails in the extra strap for best results. Most contractors use this type of system on houses that have tile roofs.
However, the double wrap strap is not always necessary. Even in high-risk hurricane zones, you may get away with a single wrap system.
Toe Nail
Toe nail refers to any hurricane tie-down system that uses nails to provide extra stability.
This system is usually used with other methods, such as clips or straps. The nails help keep the roof from sliding off the house in high winds. However, this is an old hurricane-proofing method that isn’t as effective as the metal straps we have now.
It was used in homes built in the 1960s before the newer, stronger hurricane straps were developed, and the results were often mixed. In some cases, the nails worked, and the roof stayed on, but in others, the nails pulled out, and the roof came crashing down.
Purlin Braces
These straps are commonly used to fasten purlins to the rafters. They’re not as common as some of the other types of straps, but they serve an important purpose.
Purlins are horizontal support beams that attach to the trusses and help to take some of the weight off. This assistance is crucial because it helps prevent sagging in high winds.
The purlin braces sturdy these beams, preventing them from moving around under high pressure. The braces are usually made of metal and are attached to the roof with nails or screws.
Mending Plates
Mending plates are designed to support lower load members, such as rafters and joists. The plates are typically made from steel or aluminum. They come in a variety of sizes to accommodate different loads.
Mending plates are usually used with other hurricane tie-down systems, such as clips or straps. Plates help distribute the load evenly, so the roof doesn’t collapse under pressure.
While mending plates are not required by code, they are often used in areas prone to hurricanes. This application is because they can provide extra support to the roof, and they have a proven track record of holding together tops in 140mph (225.3kph) winds.
Movement Connectors
These connect butt joints in trusses and rafters to prevent movement. They are also used to secure trusses to the top plates of walls. They come in a variety of sizes and shapes.
Butt joints are weak points in the roof because they are not as strong as other types of joints. The movement connectors help to prevent the roof from collapsing at these weak points.
These connectors are usually made of metal, but they can also be made of other materials such as plastic or wood. The best ones come from Simpson Strong-Tie, a company specializing in hurricane ties and straps.
Gable End Bracing
These are also known as ‘triangle braces’ or ‘knee braces.’ They reinforce the gable end of your roof, which is the joint that becomes the pointy part of the roof.
These braces are not the most common type of hurricane tie-down, but they are often used in areas prone to hurricanes because they can provide extra support to the gable end of the roof during a storm.
Twist Ties
These are the ties you would use to connect wood members at a corner. They are made from metal and have a twist-lock mechanism that holds the two pieces of wood together.
We have seen twist ties withstand 110 mph (177 kph) winds in a hurricane. This is especially true if you use more than three nails on each truss. We have yet to see a home completely collapse from hurricane-force winds when the proper nails and twist ties are used.
How Many Ties Do You Need?
The number of ties you need depends on the design of your roof. Most roofs will require ties in at least four roof parts: the eaves, the gables, the hips, and the valleys.
Most jurisdictions require two ties per truss at each location, but I often recommend using more than that. For example, I typically use three or four per truss at each site because a sturdier roof is more likely to stay on your house during a hurricane.
What Is the Best Type of Hurricane Tie-Down System?
The best type of hurricane tie-down system is the one that works best for your roof. For example, if you live in an area that can get more than 140mph (225.3kph) winds, you will want to use a combination of hurricane clips, straps, and mending plates.
So, there’s no one-size-fits-all answer to this question. The best type of system for your home depends on the design of your roof and the wind speed you are expecting. It’s better to be safe than sorry in this instance, so adding extra ties or straps is never a bad idea.
We recommend using more than the minimum number of tie-downs your code requires—this typically means using three or four ties per truss at each location.
Conclusion
Hurricane tie-downs are necessary to protect your roof and the structural integrity of your home.
They should be used in conjunction with other methods, such as clips or straps, to ensure a stronghold on the structure. However, the most suitable system depends on your area and the expected wind speeds during hurricane season.
So, make sure you know the code requirements for your area, and then add a few extra ties for good measure. Your future self (and home) will thank you for it!
Sources
- Weather Underground: South Florida’s Hurricane Building Code is Strong—And North Florida’s Could Be Stronger
- Air Worldwide: Improving Wind Mitigation Incentives
- How To Look At A House: The Difference Between Clip, Toe Nail, Single Wrap, and Double Wrap
- Storm Preppers: Hurricane Strap Installation
- Simpson Strong-Tie: Home