There are two main methods for building a roof.
You can either use rafters or trusses.
What’s the difference between the two, and is there a clear winner?
Read on to find out more.
Rafters Versus Trusses (What’s The Difference?)
Trusses are another method for roof support.
Unlike rafters, they are not built on-site.
They’re built in a factory.
They come to a construction site prefabricated.
This allows construction workers to install them fast.
It also means there are fewer delays.
A problem with rafters is that they’re prone to weather delays.
Trusses only take a day to install.
They are heavier than rafters, though.
They’re delivered on a semi-truck and lifted to the top of a building with a crane.
It can make building with trusses difficult in places with limited access.
Building on an island, for example, may be impossible with trusses.
It would need several boat trips to reach the construction site.
The delivery of a crane would also be difficult.
Using a helicopter may be an option, but it would increase the cost.
The most common size of board for trusses is 2” X 4”.
They’re made up of a series of boards to provide stability and strength.
Trusses are most known for their webbed design.
The design increases its integrity, especially under heavy loads.
Because of their structural integrity, trusses don’t need load-bearing interior walls.
What Are Rafters?
Rafters are a type of structural component in roofing.
They’re triangular in shape and built on-site.
Because they’re built on-site, constructing them takes a long time.
Construction workers need to take accurate measurements to cut the boards correctly.
Inaccurate measurements can compromise the integrity of the roof.
If the roof is unsafe, then the rest of the building will be unsafe.
Rafters use large and long boards in their construction.
The most common are 2 X 6 boards, but 2 X 8 boards are common for finished attics.
Building the rafters on-site allows construction workers to customize their shape.
This allows homeowners to create unique attic spaces and vaulted ceilings.
They’re also stable enough to add floors to the bottom of the rafters.
Insulation is also added to finish the attic.
Many home offices or entertainment rooms are located in finished attics with rafters.
Trusses are more affordable than rafters.
They also come with fewer weather delays.
Rafters provide more customization options for your roof and attic space.
They also use thicker boards.
How Are Rafters And Trusses Similar?
Rafters and trusses are similar in three ways:
- Used to create the structural supports for the roof/attic
- Both designed in a triangular shape
- Usually made of wood
Both rafters and trusses hold up the roof.
They use different methods to support the roof.
Despite these different methods, both are triangular in shape.
The triangular design gives the roof its slope.
Metal is sometimes used to make trusses or rafters.
The most common material used for both rafters and trusses is wood.
Several different types of wood are often used.
Those are all the similarities that rafters and trusses share.
They have far more differences.
What Are The Advantages Of Rafters?
Although the use of rafters has declined over the years, there are still advantages to using them over trusses.
Here are some of those advantages.
1. Easier Access To Materials
Rafters are easier to assemble in locations that are difficult to reach.
An island or a remote area can be difficult to reach via semi-truck.
Since trusses need a semi or something similar for delivery, they need locations with roads.
Rafters are deliverable anywhere because they come as basic materials.
You can deliver beams and boards on a truck, in a helicopter, or even with an ATV.
Whether you’re constructing in a thick jungle or a remote island, you have access to the materials needed for rafters.
2. Vaulted Ceilings
Another advantage of rafters is that you can create impressive vaulted ceilings.
The design of the rafter can feature significant slopes.
This isn’t possible with trusses.
If you want your grand entrance, a bathroom, or a bedroom to feature a vaulted ceiling, then rafters are the only option.
3. You Can Make A Finished Attic
The construction of rafters enables you to finish your attic.
Insulation and flooring are common in attics made of rafters.
This is ideal for smaller homes that need extra space.
You can use the finished attic as an office, a place for entertainment, or even a secret getaway for yourself.
Trusses are unable to support a finished attic.
While some new trusses are heading in that direction, rafters are still the go-to means.
What Are The Advantages Of Trusses?
There are a few advantages that you can receive by only using trusses for your roof.
Here are some of those advantages.
1. Save On Costs
Trusses are more affordable than rafters.
You can use the money for other home projects.
They’re cheaper because they use fewer materials and take less time to install.
2. They’re Made Accurately
Since they use computer and electronic measuring and cutting, trusses are accurate.
You won’t experience many problems installing them.
The lack of mistakes allows the installation to proceed faster.
3. No Sacrifices Of Interior Space
Using trusses to support your roof means you don’t need to worry about load-bearing walls.
You can have open spaces in your building and a strong roof.
Are Rafters Or Trusses Better For Sheds?
Rafters are better for sheds.
Smaller sheds can get away with two rafters at most.
They don’t need an interior wall to give the rafter extra support.
Rafters also give the shed more vertical space.
This can be useful for homeowners who need more storage.
In a time when personal sheds have become more common, rafters can also allow you to create unique sheds.
The shed’s design may catch the attention and appreciation of all your guests.
The only advantage of using trusses for a shed is extra stability.
If the shed is especially large or if it holds a lot of snow in winter, then trusses may be a better choice.
The stability of the trusses can ensure the snow doesn’t cause the roof to cave in at the middle.
Are Rafters More Expensive Than Trusses?
Rafters are more expensive than trusses.
There are a few reasons rafters are more expensive.
1. Requires More Materials
It takes more materials to build rafters than trusses.
Rafters are larger and use more wood.
For metal rafters, it requires more metal.
Rafters also use other support beams to give them further support.
All these materials add to the cost, especially if you’re using expensive wood.
It may seem that trusses need more materials at first.
Their webbed design gives the impression that there’s more wood than rafters, but that isn’t the case.
Trusses use smaller sizes of wood.
While a roof does need several trusses to hold it up, the amount of materials in them is still less than what is needed for rafters.
2. Special Labor To Construct Them
Not everyone can build rafters on-site.
It takes accurate and consistent measurements to assemble every rafter.
They all need to have the same measurements.
Workers will need to cut each board at the exact measurement and put them together exactly the same.
That’s tough for anyone to do, even someone who has experience.
Since trusses are factory-made, digital measurements and mechanical cutting are used.
Measurements are accurate every time.
Special labor is not required to make those measurements instead.
Rafters do require highly skilled labor.
Inexperienced and common construction workers can make mistakes.
Those mistakes are costly.
The project will need new boards.
That’s an added cost as the process starts over.
That’s more time that the homeowner needs to pay for.
If the same mistake happens again, then the process repeats.
Fewer mistakes happen when you hire experienced workers.
The problem is that they don’t come cheap.
Your labor costs will be higher with rafters than with trusses.
3. Weather Problems
Unlike trusses, rafters take a long time to construct.
It’s common to take a week to finish them.
It’s difficult to predict the weather for that long.
Sudden rain showers can cause delays.
Any time there is a delay, there’s an added cost.
Factory-built trusses don’t face this problem.
They’re constructed indoors.
If it’s raining outside, then the workers are still able to finish them.
Another problem the weather presents is damage.
Any time wood becomes wet, it’s a serious problem.
It softens the wood and makes it warp.
Too much warping can affect its shape and cut, making the wood impossible to use.
The project will need new materials in the presence of rain.
If workers are constructing during the rain, then there’s always a risk of injury.
Injuries can also slow down the project, maybe even bringing it to a halt.
The weather is one of the costliest risks of using rafters.
4. More Unique Designs Cost More
There’s a reason that trusses aren’t as expensive as rafters.
They’re built for factory measurements.
They expect the roof to be of a certain shape.
While this might mean the building is cookie-cutter, it also means it’s cheaper to build.
If you plan on using rafters to build a unique roof, then you’re going to see more costs.
You may need more rafters to compensate for the design.
That means more materials and more labor.
It can also add several days to the project.
You’ll need to pay your workers longer.
5. Load-Bearing Interior Walls
Rafters need load-bearing interior walls to maintain their integrity.
While they’re stiff and bendable in certain places, they rely on interior walls to hold them up.
Your home may not have a load-bearing wall.
To give the rafter extra security, you may need to build a load-bearing wall.
That can interfere with design plans.
It can even make rooms look unusual or unpleasant, if not planned out properly.
The cost of adding a load-bearing wall may end up being significant.
The wall may need to run the entire length of the building.
If so, then the cost increases along with it.
Trusses don’t need load-bearing walls.
Roofs use a lot of trusses to make up for load-bearing walls.
Their webbed design gives them extra stability and integrity.
This enables homeowners or building owners to design the interior the way they want.
Is It Faster To Build With Rafters Or Trusses?
It is faster to build with trusses.
The mistake that some homeowners make is that they order the trusses later in the project.
Constructing trusses takes anywhere from two weeks to two months.
During busy construction times, like the spring and summer seasons, it can take a couple of months to receive the trusses.
Ordering them before the rest of the construction begins can ensure the trusses arrive when they’re needed.
During the slow period, it’s safe to order trusses when the roof is ready.
Regardless, using trusses is faster than rafters.
Once they arrive, installation is fast.
It doesn’t need a lot of thought or extra work to install the trusses.
Each truss has markings that enable the workers to align them and secure them.
Rafters need more time.
First, the materials need to arrive.
It may take a few orders to receive the correct number of materials.
Once everything is together, the workers need to take measurements.
Then they need to check that they’re correct.
Any mistakes start the process over from scratch.
They’re cut and ready for transport.
Then the workers carry each part of the rafter to the top of the roof.
The workers then assemble the rafter.
This process repeats for every rafter.
Add in any weather delays or problems with shipments, and it can spiral.
Trusses take less time to install because most of the work is done in a controlled environment.
Are Trusses Or Rafters Stronger?
Trusses are stronger than rafters.
Here are a few reasons for this.
1. Webbed Design
A truss uses a webbed design to help distribute the weight across its frame.
Each part moves the weight around.
This ensures that no one part is ever bearing the whole load.
This is different from rafters which don’t use a webbed design.
At most, they use a few different boards to distribute the weight.
Most commonly, rafters rely on their thickness and bendable nature to take the weight.
2. Roof Uses Several Trusses
Only a few rafters make up the structural support of a roof.
A lot of trusses are used.
Each truss is only set a few feet from the next.
Because of their proximity, trusses can hold a lot of weight.
This spreads the weight across all the trusses instead of one.
Rafters have a bendable nature.
They rely on this nature to soak up some of the weight.
Over time, this can be problematic.
To give more structural support to an area, the rafter needs a load-bearing wall.
The rafter sits atop it, and the wall transfers the weight to the foundation.
Using several trusses is a more effective means of distributing weight across a surface.
3. Trusses Don’t Rely On Geometry
Several trusses support a roof.
That’s the method behind their use.
This is stronger than the method used for rafters.
Rafters use geometry to support a roof.
It relies on specific shapes and distributions of weight to make it strong.
While that’s great on paper, in practice, it can bring up some problems.
Geometry isn’t set, especially for a building.
The terrain is always shifting.
The wind is always making certain elements of the building twist and move.
Even temperature changes can cause changes in the geometry.
When the geometry changes, the structural integrity of the rafter changes.
It may have started as a strong rafter, but this may not be the case after a few years.
Trusses maintain their strength.
If the house or building shifts, then the trusses shift with them.
They’re able to compensate for the changes because of their large numbers.
Can You Install Trusses On Your Own?
It’s easier to install trusses on your own than it is to install rafters on your own.
Trusses come to the worksite with instructions.
Markings will be by cuts.
These instructions state where each truss fits.
If you understand basic construction, then you may be able to install trusses on your own.
You will, however, need access to a crane to move the trusses to the top of the building.
That’s the only aspect that may stop you.
It’s more difficult to install rafters on your own.
Here are a few reasons.
1. Rafters Need Measuring
Unless you have a lot of experience in construction, you’re likely going to make a mistake.
You can’t afford to make a mistake in measuring your rafters.
Each rafter needs accurate measuring and cutting to install the right way.
Otherwise, you’ll have a roof with gaps or little structural support.
2. You Need To Know How To Put It Together
Trusses come with instructions.
You need to know ahead of time how to make a rafter.
The correct shape, size, and where the joints attach are all things to know.
Since rafters use geometry to support the roof, doing the geometry wrong can be catastrophic.
3. You Need To Know Right Materials, Wood, And Tools
Trusses come from the factory.
You can choose what type of wood they use, or you can leave it to them.
A lot of the difficult questions are already handled.
When you install rafters on your own, you need to know what materials you’ll need.
How much of the material are you going to need?
What size of boards?
What type of wood is the best?
What tools will you need to install the rafter?
Assembly isn’t as simple as attaching the rafter to the roof.
You need to start from scratch.
There are more differences than similarities between trusses and rafters.
They’re both responsible for supporting a roof but do so in different ways.
They both use wood but different sizes of boards.
Trusses are more affordable, easier to use, and installation only takes a day.
Rafters allow you to create unique shapes for your home’s roof.
They’re also ideal for finished attics.
Depending on your project, you may find trusses are a better option than rafters.
Reading our in-depth guide above can help you decide which is the best option for your project.