Installing pergola rafters is one of the last steps to finishing a DIY pergola. While rafter installation can be time-consuming, the steps are repetitive.
In this tutorial, we will show you a quick, easy, and inexpensive way to install pergola rafters without brackets.
As a recap, here are the steps we’ve completed so far:
- Installing Pergola Post Brackets
- Staining and Sealing the Wood
- Installing the Pergola Posts
- Creating a Wall Mount
- Finishing the Pergola Wall-Mount Frame
How Should You Install Pergola Rafters?
Metal brackets are popular for rafter installation. They’re graded for outdoor use and provide a secure way to hold lumber in place. However, because you need to place brackets on each end of each board, they don’t provide a clean, modern aesthetic.
Of course, construction isn’t all about the aesthetic appeal – you also want the finished product to be safe and secure. That’s why the method we’re using is a win-win. The installation of each rafter is fast, the connection is secure, and it will last as long as the bracket method but for a lower cost.
Instead of metal brackets, we’ll be securing our rafters to the frame using screws and pocket holes.
How to Install Pergola Rafters without Brackets
Before you begin installing your pergola rafters, find the center on your perpendicular frame boards.
If you have a center beam, as this pergola does, you’ll want to find the center on each side. Unfortunately for us, our center beam boards are a bit bowed. We can’t install rafters to a center beam that’s not straight. So, our first order of business is to straighten it.
Step 1: Straighten Your Center Beam
At the center point on the wall-mounted frame boards, we installed a (temporary) screw eye.
To install a screw eye, get it started into the board with your hands, then use a screwdriver through the eye to tighten it. We chose the center point because we will install our center rafters first, and the rafter will cover the hole once we remove the screw eye.
Once the screw eye is secure into the center of the wall-mounted frame, hook one end of a ratcheting strap into the screw eye.
The other end of the ratcheting strap will loop twice (it’s only shown once here, but you’ll want to do it twice) around the center beam, just slightly off-center, then hook to itself. Don’t wrap the strap around the part of the beam that will connect with the rafter.
The setup will look like this. Now begin ratcheting the strap tight, which will pull the center beam straight. Watch this center beam closely; you don’t want to overtighten it, as that will cause the opposite problem. Don’t be afraid of a little creaking or complaining of the wood.
You can see here how the center beam is straight now.
Here’s a top(ish) view. We’ll use the ratcheting strap until we install the first rafter on the right-side section.
Step 2: Measure and Cut Your Rafter Boards
Measure, at your center marks, from the inside edge of your frame to the inside edge of your center beam to determine the rafter length. Mark, then cut this length with a miter saw.
Step 3: Drill Pocket Holes at the End of Each Rafter
Use an HD Kreg jig to drill two holes per end on your rafter board. You’ll need a partner for help – the jig will try to kick out from under you as you drill.
Have a helper place his/her foot against the end of the HD Kreg jig to hold it against the end of your board.
Press down firmly with one arm as you drill your pocket holes. Doing this secures the HD jig into place, both from the end of your board and onto the face of your board.
Drill two pocket holes, each about 1” away from the sides of the board, onto each end of your rafter. These pocket holes should share the same face of the board so that one side of your pergola rafters looks like they’re floating.
Step 4: Attach the Rafters to the Frame
Grab your right-angle Kreg clamp for the end of the rafter you’re connecting to a floating frame board.
At the center mark (these should be marked as lines on the top of your frame boards), with your pocket holes facing the “back” side of your pergola, use the right-angle Kreg clamp to hold your rafter board in position. Using HD Kreg screws (2-1/2” heavy-duty pocket screws rated for outdoor use), attach your rafter to the frame.
Tip: After you’ve screwed in one HD Kreg screw, remove the clamp. Use a level or a right-angle triangle to determine how perpendicular your rafter is. You might be surprised that eyeballing it can be quite off from square (at least, I was surprised.) Square up the board, then install your second HD pocket screw.
Repeat the process for the second side of your first center rafter, making sure everything is square, level, and flush.
In the perfect scenario, everything will align as it should, but if you have to choose, line up the bottom sides of your rafter + frame boards since they will be visible. The top part of your pergola won’t be all that noticeable. Use a scrap board and hammer to create a flat connection on the bottom ends of your boards, if necessary.
Here is a photo of the first center rafter fully installed. Those HD pocket screws are so strong; this rafter is as sturdy as can be.
Remember how your pergola still has the ratcheting strap attached to its center beam?
When we removed the strap, the center beam pushed outward ever so slightly, affecting the precise straightness of the outside frame boards. So, to maintain a straight center board until we installed both center rafters, we moved the screw eye and repositioned it 10” (at the next rafter placement.) We repeated the ratchet strap attachment, tightening it until everything was straightened up again. Then we installed the second center rafter onto a squared-up frame and center beam.
Step 5: Remove the Ratchet Strap After Center Rafter Installation
Here, we’ve installed both center rafters and can now remove the ratcheting strap for good.
The center beam is straight after we removed the strap, which means the outer frame board is straight as well. Everything is square, putting us in the perfect position for installing the rest of the pergola rafters.
Step 6: Install the Remaining Rafters
From the center marks of all perpendicular frame boards (including the center beam), we used a simple ruler to mark 10” spaces since we’re installing our rafters at 10” center-to-center.
You can see, from this “front” view of the pergola, that the rafters are seamlessly connected to the framing. We love the floating, minimalist look, especially when the two-tone pergola provides enough visual activity.
Now that you’ve installed the center rafters, follow the same steps to install the rest. Work from the side of the rafter that has the pocket screws for the easiest installation.
Here, you can see how the pocket holes line up from one side. They aren’t very noticeable, especially up high on your pergola. However, we’ll still need to stain the insides of the pocket holes for wood protection.
And here is a view of the “floating” slats.
We recommend installing one or two rafters on one side of your center beam, then switching and installing one or two on the other side. Going back and forth ensures that everything stays in line.
After you’ve installed the rafters from your center rafter’s pocket hole side to the outer frame, you’re halfway done. As long as you’ve marked the rafter positions on the tops of your frame boards and center beams, you can jump to the top of your pergola and begin installing rafters from the outside in (toward center).
It’s not impossible to install the rafters with the pocket holes on the inside (which is why 10” or greater spacing is important), but it’s much easier to work in a larger space that a bigger air gap provides.
Don’t feel like you have to work in the direction of the center rafter outward. Once the center rafter is installed, do whatever works best for you with the other rafters’ installation direction.
Here, you can see that we’ll eventually have only a 10” air gap to work in on the rafters closest to the center rafter
But for the installation of all other rafters on the second half of the pergola, we’ll have plenty of room to move around. The extra room is helpful for measuring, marking, fitting the board, leveling it, clamping it, and screwing it into place.
You’ll want two people on ladders, one on each end of your rafter boards, at all times. The no-bracket method requires that one person holds one end of the rafter while the other person installs the opposite end. It’s definitely not a one-person installation opportunity.
After you’ve installed all the rafters, step back and enjoy the results of your hard work.
Pergola Slats Installation Tips
With 2×6 redwood rafters spaced 10” apart, there is plenty of shading opportunity while still providing a nice view of the open sky. These features make pergolas distinct from completely covered patios.
Be sure, as you’re installing the second rafter of each line, to align the rafter ends and create a “straight” line, even though it’s actually two rafters separated by a center beam.
If, for some reason, a rafter ends up being 1/4” off its center marking (hey, things like this happen in real life, right?), align the second rafter end with this off-center one, or at least split the difference. You don’t want a visual split between your two boards.
When you compare this straight center beam with the bowed original, you’ll see why it’s so important to take care of it from the very beginning of rafter installation. Don’t think your rafter boards themselves will straighten out a doubled-up center beam.
Capping Pergola Posts
Later, we will be taking off the tips of the pergola posts and capping them so they don’t swell or split. But for now, the pergola posts extend upward about a foot from the top. If you like this look, consider your pergola work complete.
The two-tone nature of this pergola is one of our favorite features. You’ll notice that there are no cross-boards (slats) on top of the rafters, as is sometimes the case with pergolas. We wanted a clean, minimal look for this contemporary pergola. The 2×6 rafter size provides plenty of shade potential without adding another layer of visual busyness.
Even against the house, the black and natural stains look well together.
While two-tone architecture has been around for a very long time, it’s just as relevant today as it was in decades (or more) past.
Of course, a monotone wood pergola is beautiful in its own right. In all black, this pergola would make quite a dramatic statement.
If we stained all the slats black to match the pergola frame, it would appear to be a solid roof from certain angles.
You can see the final result of the pocket holes, visible from the back side of the pergola but not very noticeable. Much less noticeable than metal brackets would be, which was what we wanted.
We hope you found this tutorial on how to install pergola rafters helpful.
As an FYI: Many people refer to the main pergola boards as rafters (as we have done in this tutorial) and to the perpendicular shade boards on top of the rafters as slats (there are none of these in this tutorial). Others call all the boards slats.
Either way, enjoy finishing up the top of your pergola. It’s a beautiful feature that will add immeasurable value to your life and to your home.