Collar Ties: How To Install, Codes, & Construction (Complete Guide)

When planning your home, you will have to learn to carefully consider the materials and locations of things you never knew existed. Something that leaves many people scratching their heads is the use of collar ties and the regulations accompanying them.

A collar tie prevents roof rafters from moving apart if any pressure is applied upwards or downwards on them. These collar ties must be no smaller than 1×6 lumber, usually spaced 48 inches apart from each other on the roof rafters, and must be near or in the upper third of the rafters.

This is just the most basic information regarding collar ties and some regulations that guide their installation. When you plan to build an addition to your own home, or you want to know how your builders have to do something, you will need to know a lot more.

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Code Restrictions On Collar Ties

The complete codebook of what your collar ties are allowed to look like, what they are meant to do, and all the restrictions that apply to them require years of study to understand fully.

This is why you need an engineer that has done the studies to look at your plans and make changes according to what they know.

However, collar ties have three necessary codes that apply to them that will affect how you will be constructing the collar ties for your home. These are the three main characteristics of collar tie design that you should pay special attention to when planning:

  • Collar tie lumber size
  • Collar tie positioning on the rafters
  • Spacing between collar ties

The exact dimensions needed may be calculated in the planning stages, but you can use these three codes for your planning. In the next few sections, I’ll take a more in-depth look at the three main code restrictions regarding collar ties.

Collar Tie Size Regulations

The maximum size of a collar tie is not clearly defined, and the size of the collar tie overall needs to be determined by calculating the total amount of weight that the roof may have to carry. You need to plan for the weight of the roof itself and the added weight of snow if that’s a concern.

The smallest that a collar tie can be is 1×6, which is not very thick. Most builders and engineers prefer to use a 2×4 as this gives a lot more stability and strength. When it comes to your house’s support structure, being over-engineered is always better than the alternative.

Collar Tie Position Regulations

The regulations for collar ties specify that they must be in the upper third of the rafters, near where the two ends of the rafters will be meeting at the peak of the roof. Installing them lower makes them too long, causing them to strain and not properly support the rafters and roof.

This provides the support needed to keep the rafters connected, creating strength by triangulating the system. A good collar tie will be in this area, but if required, engineers can place them higher to make space to move in the attic or replace them entirely with ridge straps.

Collar Tie Spacing Regulations

One of the most regulated areas of using collar ties is the distance between each one. Collar ties cannot be spaced out more than four feet on center. This means that your collar ties must be placed every four feet. If you have two feet between rafters, every second one must have a collar tie.

Further, if you have an odd distance between each rafter, you will need to adjust, as the collar ties may not be further than four feet apart. Rafters with 2.5 feet between each other would need their own collar tie; therefore, the collar ties help decide how the rafters are spaced.

Where Do You Use Collar Ties?

Collar ties are used in most homes with rafters built onto the roof, with the two pieces of the rafters meeting each other in the centerline of the house. The collar ties complete the triangulation of the roof, ensuring that it does not fall apart when a high amount of weight is applied.

Houses are typically built without A-frames for the roof, with the attic space as an essential room have collar ties or other ways to connect the two sides of the rafters. You will need to use collar ties, especially if you have a larger house and roof, focusing on strengthening the roof.

The collar ties serve the purpose of helping the roof take the brunt of the weight placed on top of the roof. Many people will use collar ties specifically when they know an area is likely to experience a lot of snow or earthquakes.

Why Would You Not Use Collar Ties?

Collar ties are significant when you want to strengthen a roof; however, many people find them extremely intrusive. Usually, when a roof area is used as an extra room, like an attic or an extension of the house, collar ties will not support the roof.

Further, we have seen many people prefer to have their rafters not connected with collar ties as these take up too much space. In areas with no snowfall and no earthquakes, you can easily enjoy not having collar ties as well, as other less intrusive methods will give stability.

Many homes worldwide have no collar ties, relying instead on the structural strength provided by other joining methods. Roofs with more dramatic angles in their roof will benefit from not having the collar ties, allowing them to push the weight straight down comfortably.

A Step-By-Step Guide to Installing Collar Ties

Now that you know what code requirements there are for collar ties and the various ways you will need to consider them when building, you need to know how to make them. A few things to look out for when making collar ties, as they can be tricky the first time.

Your engineer, architect, and veteran builders will all have the knowledge required to help you professionally install them. However, you may be alone or just ahead of schedule and want to start installing them. Looking at the designs will tell you the basic design your collar ties require.

Step 1. Determine the Regularity

This should have been done on the planning stage, but just in case, we are covering this again, as it will determine how many collar ties you have to cut while on the ground. Your collar ties should be placed once every four feet; assuming you have a roof that is just over 30 feet long, we can calculate.

With that, assuming that you have placed rafters every two feet, we know there are 15 rafters (both ends need collar ties). In total, you will need eight collar ties to place one on each end and then place a collar tie on every second rafter, with one end of the roof having two collar ties next to each other.

Step 2. Choose the Collar Tie Size

Before we start cutting and measuring, we need to choose the total size of your collar tie, with smaller collar ties perfect for smaller homes. The code does say that 1×6 is the minimum. However, this will not be strong enough when things become difficult.

Most builders and engineers prefer to use the tried and tested size of 2×4 as these pieces are usually high-quality and are easily rigid enough to support any weight. When building and installing collar ties, we recommend sticking with 2x4s or larger as 1x6s can be surprisingly flimsy.

Step 3. Measure the Length

Your engineer might be happy to use four nails to hold your collar tie, or your rafters might be at such a low angle that he wants to use up to eight nails. You will have to measure the total length of the collar tie depending on whether you are cutting the collar tie to the angle of the rafters.

Square collar ties can handle fewer nails than angles collar ties, which means that angled collar ties must be longer to accommodate the angled cuts on their ends. An excellent way to do this is to cut one collar tie to length and then use it to measure every other collar tie you are cutting.

Step 4. Position the Collar Tie

If you are working with a team, this will take only a few minutes to do, marking where the collar tie needs to be before installing it. If you are working alone, we recommend getting a few g-clamps to help hold the collar ties in place before attaching them completely.

When the ends are cut at an angle, you should already have marked lines to where the collar ties should be; use the angle and the lines to place the collar tie. We further recommend having both sides perfectly aligned with the lines and the angles before attaching completely.

Step 5. Nail the Color Tie Into Place

The most common way to secure a collar tie is with a set of nails; we recommend using 16D nails around three and a half inches long. Four nails on each side should be more than enough to hold the collar tie in place. However, some engineers can ask for much more.

This is why having the ends cut at the right angle is essential. If the ends are left square, there won’t be enough space to allow for more nails. Usually, you will be aware of what is needed when planning if you find there is not enough space for the planned amount of nails.

Step 6. Move Onto the Next Collar Tie

The most bothersome part of installing collar ties is that it can quickly become repetitive, with the clamps requiring to be moved with each installation. If you have a friend or more people to help install the collar ties, the entire process will be made significantly easier as you go.

As with all things engineering, you will be a lot better as you continue to practice, with the second collar tie going in significantly faster than the first. As you continue to move through the roof, you will become more proficient and learn what not to do.

What Size and Material are Collar Ties?

When it comes to what materials to use for your collar ties, many people may be left scratching their heads, especially when they first start using them. A significantly large number of people never realize that the material choices affect the overall strength of their construction.

Nearly all color ties used in residential construction are wood, though occasionally, you’ll find ones made from steel.

Collar Tie TypeProsConsAdditional Notes
Wood Smaller than 2×4InexpensiveOften isn’t heavy-duty enoughThe minimum lumber size for collar ties is 1×6
2×4 WoodVery common, strong, and cheapNot many cons, but they may not be large enoughThe most common collar tie material and size
2×6 WoodA good balance of strength and costThey can start becoming expensiveA good step up from a 2×4
2×8 WoodVery sturdy and tall lots of surface area contactExpensiveLots of surface area for extra nails
Wood Larger than 2×8Extremely sturdy and durableExpensive and heavyUsually too tall and impractical
SteelLow maintenance, strong, and durableExpensive and heavyOverkill in most situations but sometimes worth it

Which collar tie material you use in your construction project depends largely on your specific situation and needs. Make sure to consult a professional if you have any questions or doubts.

With collar ties, the size of the wood you use determines what types of wood you will have, with the location of the joints further changing what the material is made from. When installing your collar ties, you need to know as much about the materials as you can so you make an informed decision.

2×4, 2×6, and 2×8 Collar Ties

The most common sizes used for your collar ties are made from pine wood in most situations as they are meant to be used in locations that will not be seen. Many people assume that they can have stronger collar ties when using different materials; however, pine always works.

It should be noted that whichever material is available in the areas around you will also work, as the strength of the collar tie is from the combined strength of the system.

When professionally installed, which collar tie material you use matters less because the whole structure works together to provide ample stability and support.

Larger, Covered Collar Ties

House designs with open rafters or attics require special, larger collar ties often treated, oiled, or otherwise coated to look nice. When doing this, the collar tie material needs to be considered and treated before final installation.

Depending on the design specifications, these collar ties can be made from cherry wood, hardwoods, or steel beams. Many people choose exotic woods or wood stains because it looks fantastic when the work has been done and everything is completed.

Conclusion

Collar ties only seem complicated when you have never heard of them before. Their installation, measurement, and planning can be pretty easy once you know the basic codes and rules. We recommend brushing up on some local code limitations before planning your project, to allow the best use of material.

Whatever you do, please don’t ignore the safety regulations that your country has when building a roof. They are there for a reason and help to keep construction safe, repeatable, and structured for everyone’s safety.

Sources

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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