How to Build a Pergola on a Deck

How to Build a Pergola on a Deck

Adding a Backyard Shade Pergola to Our Deck

We enjoy our deck. It gets a wonderful breeze most of the summer that keeps the bugs down and helps us stay cool.

At some point we decided we wanted to add a little bit of shade to our deck. An actual screen room was a little too ambitious (and costly), so we decided on a DIY pergola.

A deck pergola offers a little bit of shade, but keeps that open feeling of being outside.

Now as you might know from previous musings on our blog, The Heathered Nest, we have a pretty large deck that we inherited when we bought this house. We spent a fair amount of time giving it a makeover this past summer. 

Just to give you an idea of how much time, here’s a picture of how the deck looked before this project:

We removed the railing from the raised deck, cleaned it up, and added a solid deck stain (that looks like paint but should hold up so much better!).

Then we added a pergola to the existing deck to add shade.

Can you put a pergola on a raised deck?

Yes! We are living proof that you can put a pergola on an existing raised deck or floating deck.

Depending on the height of your deck, you might want to add a railing to the DIY deck pergola (or the deck itself), and you’ll want to make sure the deck pergola is reinforced with heavy duty hardware and connections since the additional height may catch more wind resistance.

DIY Deck Pergola Tutorial

The simple DIY deck pergola has been one of our favorite features, so today, we’d like to talk about how we DIY’d ours, and hopefully inspire some of you to give a project like this a try at home, too!

Video: How to Build a DIY Deck Pergola

The tutorial and video below show how to build a pergola on a deck. Watch it here on our YouTube channel and be sure to subscribe for more videos!

Planning a DIY Pergola on an Existing Deck

***WARNING!! This is a construction project which requires use of power tools, heavy construction materials, and a working knowledge of safe DIY practices. If you are not comfortable with any of these required skills, please save yourself injury, trips to the ER,  death, dismemberment, physical trauma, or emotional trauma caused by a nagging husband or wife asking you why you cannot seem to complete this project. This is not a project for beginners. By utilizing this tutorial, you agree utilize information contained herein at your own risk. Neither nor will assume liability for any injuries, etc, incurred as a result of following the tutorial information written in this post. You must also ensure you have checked and are in compliance with any local building codes pertinent to this project. Installation requirements will vary based upon factors such as the surface on which the pergola will stand, be it ground, a deck or patio, etc. ***

Before you start hoisting beams in the air and getting that saw buzzing, make sure you’ve got a good DIY deck pergola plan worked out.

Decide exactly where you’re building your pergola — ours was on top of our existing deck which is raised a bit above the yard level.

Then, you need to determine the size of the pergola you’d like to build. Ours is about 14’x14’ (this is the distance between the 6×6 posts).

The strength and structural integrity of your pergola will depend greatly upon the size of the structure you are planning to build. Choose your lumber sizes for the needed strength over the span of the project.

Again, be sure to check local building codes for compliance before beginning the project.

For our 14-foot square DIY deck pergola, we used 12′ 6×6 posts, 22′ 2×2 beams, and 16′ 2×10 joists — all pressure treated wood.

If the planning feels overwhelming, you can order a DIY pergola kit, shipped to your door instead.

Why are the beams and joists so much longer than the pergola size? We chose a simple pergola design, and wanted a wide overhang with curved beam and joist ends to dress up the basic square pergola. Our pattern was about 2′ long on the boards. If you choose square ends for your beams and joists, or a simpler shorter decorative curved end, you may not need as much overhang.

Framing: Parts of a Pergola

We’ll be using certain terms throughout the post for parts of the pergola. (See image below.)

For our 14′ x 14′ large DIY deck pergola, we used 6×6 posts, 2×12 beams, and 2×10 joists.

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DIY Deck Pergola Materials & Hardware (14×14 pergola)

Depending on the size of your pergola and the available materials, your shopping list will vary. We used:

Try a DIY shortcut: order a pre-made wood pergola kit shipped right to your door instead. (Pergola kits also come in metal/steel/aluminum and vinyl if you prefer.)

What type of wood should I build a pergola from?

Pergolas (and other outdoor structures like arbors and gazebos) should be built from a weather-resistant wood such as cedar or redwood, or pressure-treated timbers available at the lumber yard.

Be sure to also get corrosion resistant bolts and screws rated for outdoor weather *and* for exposure to pressure treated lumber.

Tools to Build a DIY Pergola

Step by Step DIY Deck Pergola Tutorial

 Step 1. Set the post anchors on the deck

With the location and size determined, we can get started on the pergola construction.

How to Anchor a Pergola to a Wood Deck

If, like ours, your pergola will be sitting on top of an existing deck, the 6×6 pergola posts must be located over top of the existing support structure. This means locating the existing deck joists.

Once the location of the 6×6’s posts has been determined, the 6×6 metal post anchors can be installed. The post anchors have a hole in the middle so that you can attach it to the deck joist.

I drilled a pilot hole using a 1/8” bit. Then the anchor is secured to the existing joist with a 1/4” lag bolt. I used an impact drill for this, but you could also use an old fashioned socket set.

Justin used similar post bases to add an arched arbor to their wood deck here.

How to Anchor a Pergola to a Concrete Patio or In-Ground Footing

If you want to build your pergola on an existing concrete slab or directly on the ground, you will need to install your 6×6 posts differently.

For an existing concrete slab, you can use the same post anchors, but you will need to use a hammer drill and special concrete anchors to attach the post anchor to the slab.

If you are going to build your pergola directly on the ground, you will need to dig holes for each of the posts, add some gravel, fill the hole with concrete, and set the post.  The hole depth will depend on local building codes, but is normally between 24″ and 36″ deep, and 24″ in diameter.

Step 2. Raise the 6×6 posts and add temporary bracing

Installing 6x6 posts, using 2x4's for temporary bracing | DIY deck pergola tutorial
Installing 6×6 posts, using 2×4’s for temporary bracing.

With the anchors now installed, its almost time to lift the 6×6 posts into place. This job will take at least two people. Hopefully, you have a buddy that owes you. Be very careful, because these things are heavy!

But before you actually lift up the posts, we need to prep them a bit.

We figured this little tip out the hard way…shave off about 1/8” to ¼” off of one side of the 6×6 post, just at the very bottom. This will allow the post to slide into the post base anchor bracket much easier.

Also, pre-drill a hole in the bottom of the 6×6 post, right in the middle. Drill a 1” hole about 2” deep. This will allow the 6×6 post to sit flush with the ground and not be held up by that lag bolt we just installed.

Post installed into an anchor on the deck, DIY pergola tutorial
6×6 post installed into anchor. Notice how we shaved a touch off the side of the post to allow it to fit more easily into the anchor.

After you’ve prepped the 6×6 pergola post for the anchor bracket, install it (with a buddy or two):

Bracing posts

I simply screwed the 2×4’s directly into the 6×6 post and into my existing deck. Check out the pics to see exactly how this should look.

Think about where you put the bracing because this will be up for the duration of the project. Be sure not only that your bracing is securing the beams, but also that it will not get in your way as you continue constructing.

Continue this same procedure with the remaining 3 posts.

Step 3. Cut the decorative ends of beams

Before installing the four 2×12 beams to the front and back of the structure, you can use a jigsaw to make the ends look a bit more decorative. Pinterest is a great source for design inspiration like this.

See some simple beam end examples (and templates) on this simple wood wedding arch arbor plan or this gothic arch arbor plan.

Once you find a design aesthetic/look you like, using a pencil, simply sketch the shape freehand onto the end of one of your 2x12s.

Once you’ve sketched a look you’re happy with, use the jig saw to cut along your sketched line.

The scrap piece that has been removed from your beam now becomes a template used to cut the edges of the remaining beams. This ensures they will all be identical.

After it was cut, we used a palm sander to smooth out the edges of the jigsawed pattern on the beam. Our pattern took up about 2’ of space.

You need to apply this pattern to both ends of the beam, not just one. How large or small, or the shape of this pattern in general are all personal preferences.

How to cut decorative ends on pergola beams | DIY deck pergola tutorial
Using jigsaw to cut decorative ends of pergola beams.

Step 4. Install beams to front and back of structure.

It’s almost time to “sandwich” the front and back posts with two sets of 2×12 beams.

But before we hoist these big pieces of wood up, we are going to prepare some bracing that will help hold the beam in place while we get it bolted. We’ll do that with some 2×4 scraps.

Cut a few 2×4’s approximately 2′ in length, and screw them into the 6×6 posts at the height that you want your 2×12 beams to sit.

Once you’ve secured your 2×4 bracing pieces, then lift the first 2×12, and rest it on the 2×4 bracing. Check for level. Then lift the second 2×12 beam into place on the opposite side of the post.

I also clamped the beams to the post to help temporarily secure them until I could bolt the beams to the posts.

The beams are secured to the 6×6 posts with two carriage bolts. To install a carriage bolt, first drill a pilot holes through each beam and post attachment point, then install and tighten the carriage bolt, washers, and nut.

Once you have the carriage bolts installed and tightened into the posts, the 2×4 braces can be removed.

IMPORTANT NOTE: We later trimmed our pergola posts to height to match the beams/joist heights. It is safest, and a better procedure, however, not to erect your posts until they are sized correctly — so we’d recommend trimming the posts before installing.

Beautiful simple DIY deck pergola on an existing deck, full how-to and tutorial from The Heathered Nest on
Appearance of the beams “sandwiching” the 6×6 posts from below the structure.

Step 5. Cut the decorative ends on the joists

2×10’s are the material used for the joists. While not required, it adds some decorative “flair” to cut the same pattern into the ends of your joists that you cut on your 2×12 beams with the jigsaw.

Be sure to keep this extra decorative end length in mind when you are determining board lengths for your joists!

Since the dimension of the joists are smaller than the beams, the scale of the pattern will be slightly different.

So again, sketch your pattern with a pencil onto one of your joists. Once comfortable with the design, cut it out with your jigsaw. The discarded piece of wood will be used as a template for cutting the pattern into the remaining 2×10 joists. 

Since our pergola butted up against our house on one side, we only needed to cut this pattern on one end of our joists. But this may not be the case for your particular project.

DIY deck pergola against the house, with string lights on a deck, The Heathered Nest for
Rear of our pergola abuts house, so no decorative ends were cut on this side.

Step 6. Install joists around the pergola beams

In our case, before we moved onto the joist installation, we had to trim excess length from the top our 6×6 posts. It is safest, and a better procedure, however, not to erect your posts until they are sized correctly.

Our joists are 9″, so we want the top of the 6×6 post to rise only about 8″ above the 2×12 beams so that they are just shy of the height of our joists.  This will allow us to bolt the joists into the 6×6 post, but not have the 6×6 post sticking up above the joists.

The first four joists that you will install are those on either end of the pergola that will sandwich the 6×6 posts above the 2×12 beams.

Use two carriage bolts to secure the joists around the 6×6 post in all four corners of your pergola.

Step 7. Install joists across the top of the pergola structure

The remaining joists are spaced equally between the posts. They ended up about 2’ apart.

To secure these joists to the beams, I used 2.5” screws and screwed them at an angle into the beams.

If you live in a high-wind area, you’ll want to consider strengthening the structure with hurricane tie brackets like these as well.

Step 8. Brace top of joists with 2×4 rafters

Above the DIY deck pergola joists, and perpendicular to them, we’d recommend installing four (4) rows of 2x4s as rafters.  This will help keep the joists straight and reduce warping.  

Screw in one row each at the front and back, and then the other two rows spaced evenly in between. Lay the 2×4’s flat and secure them to each joist using 4″ screws.

On our pergola, instead of using the 2x4s on top, we did something a little different. We installed lattice and screen material to add extra shade.

That is a separate project, and is not part of this particular post, but you could tackle that additional work if you desired. 

Step 9. Finish, Brace, and Decorate

Your pergola structure is complete! You can now remove the 2x4s that were bracing the posts.

Now your pergola is free standing, so it will sway just a little bit. Ours did not sway too much, but if it does, you can always add in some bracing at the top corners to help stiffen it up.

All that’s left to do is sit out there and enjoy! I did add some curtains and lighting (plus a ping ping dining table) to make it cozy.

We had a lot of work to get us to the point where we could say we really loved our outdoor space, but this pergola has been a a great addition to our deck. Hope that it may be to yours as well.

This content was originally published here.