Introduction: How to Build a Pergola on a Concrete Patio in Two Days

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About: If there's one thing I've learned about being an adult, it is this: there's always another project. Over the years, I've tackled a ton of projects and built some cool stuff, and now I'd like to help people wh…

Building a pergola is a quick way to add a touch of class to your outdoor space, and it's certainly something a homeowner can tackle by him or herself, and can even finish in a couple of days if sufficiently motivated. Additionally, for those who aren't very experienced in building things with wood, this is a good starter project to develop skills that will readily transfer to other projects.

I'll note right away that I was able to build this pergola in two days; however, I've done this sort of thing a few times now, and I have a lot of power tools that make the job easier. If your skills aren't high and/or you have a limited tool set, it will take longer. Don't despair though - this still makes a great fair-weather weekend project that can be built over a couple weeks.

In the steps that follow, I link to videos I made for the build. The links go directly to the timestamp in the video pertaining to that particular step, so don't think I'm just spamming the same video over and over 😉 You can also watch the in-depth videos in this playlist. My intent for this Instructable, with the videos to complement, is to be the most comprehensive tutorial online for building a pergola.

If you like what you see, subscribe to my YouTube channel for more!

Also, check these links if you are looking for premade pergola plans or a custom pergola for your own yard.

Supplies

The materials list below will construct a pergola that covers and area approximately 10 feet by 14 feet and is 8 feet tall. You will have to update the bill of material for different configurations. The total material cost for my pergola was about $750 in 2019.

Since this is outdoor construction, pressure-treated (PT) lumber is recommended. I am fortunate to have CedarTone lumber available near me, which combines the longevity benefits of PT wood with an attractive brownish colorant. You can also buy the green PT lumber and stain it with an exterior-grade stain. All dimensions are given in US customary units and use US nominal dimensional lumber sizes.

I have provided some affiliate links below for products and tools I used, or those very similar.

  • (4) 6x6x8ft (posts)
  • (4) 2x8x10ft (secondary beams)
  • (4) 2x8x14ft (main beams)
  • (11) 2x6x10ft (rafters)
  • (12) 2x4x14ft (purlins)
  • (4) Simpson APB66 ornamental post base
  • (4) 5/8" dia x 4" long Simpson Titen HD concrete anchors, stainless steel
  • (40) 2-7/8" HeadLOK structural wood screws (or 3/8" dia. galvanized lag screws of equivalent length)
  • (32) 4-1/2" HeadLOK structural wood screws (or 3/8" dia. galvanized lag screws of equivalent length)
  • 2# galvanized 16D framing nails
  • Unless you have someone who can hold things in place for a long time, get another (8) 2x4x8ft boards (no need to be PT) for temporary bracing

Required Tools:

Optional Tools:

Step 1: Conceptual Design and Planning

----Before starting a pergola project, check your local building code and permitting requirements for such a structure. These vary by jurisdiction, so I can't provide any advice beyond contacting your local municipality.----

All good designs start with a sketch.

I first started with a couple rough sketches on some scratch paper, just to get the idea out of my head. After that, I took measurements of my patio to determine the size of the pergola that could physically fit in the space. I have an added constraint in that the second story of my house overhangs the patio slightly (third picture), so I had to modify the "typical" pergola layout somewhat.

I find that generating a model in SketchUp is very beneficial to get a sense of the look of a project and its relation to physical space. There are even plugins that automatically generate a bill of material for the required wood pieces, saving having to tally everything manually.

Obviously, you're not married to your initial design, and you'll see as the project progresses that I deviated a bit from the initial design.

With your design settled upon, determine the required quantities of material and place the order at your local lumberyard. Fair warning, some boards may be special order and take a while to come in. I think my order ultimately took about a month to be delivered.

If designing your own pergola isn't something you're comfortable with, I offer premade pergola plans on my website. These include plenty of drawing details for construction and a detailed schedule of materials, so you know exactly what to order.

Attachments

Step 2: Laying Out the Post Bases

The first step in building the pergola is to lay out the locations of the post bases. This is one step where a bit of attention to detail can save you headaches down the road, so take your time to lay things out correctly.

Start by establishing a chalk line for one of the edges of your posts. I chose the front edge for convenience and because prior measurements showed that the concrete slab didn't have entirely square sides. This line will be the basis for your measurements from here on in.

Next, pick one side to start marking a line perpendicular to your first line. The easiest way to do this is with a couple of tape measures and establish a 3-4-5 right triangle. The 3- and 4-length sides will be the two perpendicular lines, and the 5-length is the diagonal distance between them. Thanks to geometry, we know that this forms a perfectly square corner.

Pick a point on your first line to be the Outer Corner of the post, measure 3 feet away from it, and place Mark #1. Next, take your second tape measure and extend it to show the 4-foot mark, and put the leading end of it on the Outer Corner mark. Use the other tape measure, extended to show 5 feet, and put the leading end on Mark #1. Where the 4-foot and 5-foot marks intersect, place Mark #2.

Using your chalk line again. stretch it so that it intersects both the Outer Corner mark and Mark #2. Snap the line, which is now perpendicular to your first line. Repeat these steps on the other side. Satisfied that you now have three lines, two of which are perpendicular to the first, measure back from the two Outer Corner marks to establish the overall perimeter of your posts.

Step 3: Install the Post Bases

With the perimeter of the posts marked, now it time to install the post bases. Starting at one corner, place the corner of the base at the previously-marked Outer Corner. Mark the center of the post base and move the base to the side.

Using the hammer drill and a 5/8" dia. carbide-tipped bit, drill on the center mark to a depth of about 4-1/4". It's possible that you will drill entirely through your concrete patio since concrete thicknesses 4" to 6" are not uncommon for patios. Use a broom (or air compressor blow gun) to clear the dust.

Replace the post base to its previous location in the corner. With a ratchet and appropriately-sized socket (or impact gun), tighten the Titen HD concrete anchor, fastening the post base to the concrete surface. There should be no play in the post base when you wiggle it.

Repeat these steps for all four corners of the pergola.

Step 4: Measure the Post Offsets Due to Patio Slope

If your patio is anything like mine, it slopes away from your house for drainage. This presents the obvious problem that the posts can't be all the same length, otherwise the top of the pergola won't be level. To mitigate this, the post offsets must be measured from a reference point and all measured and cut accordingly.

The sill of my patio door proved to be a convenient reference point. In order to measure off these, I put together a couple scraps of wood to extend the reference line out to the same line as the post bases. Then I clamped this extension to the door sill to hold it in place and tied one end of a string line to it. On the opposite end of the line of post bases, I drove in a wooden stake and tied the string line to it. You'll want to make sure that the string line is very tight and is also level. This string line is now at the exact same elevation as the door sill.

When you're satisfied with the string line, measure the distance between the string and the bottom of the post base, and record this number. Do the same with the next post base in line, then repeat these steps for the other side of the pergola. You should have four measurements written down that correlate to each corner of the pergola. It will be convenient to name these "A" through "D" to keep things straight or some other naming scheme that suits your taste.

In my case, since I had to contend with the second story overhang, I also measured this height with respect to the door sill.

Step 5: Mark the Posts for Cutting and Trim to Length

The length of the posts is determined based on the offsets measured in the previous step. Begin by marking each post "A" through "D", and then measure from the bottom of the post the offset length you previously recorded for each. Use a square to transfer this line across the width of the post.

Next, start with the longest measured offset - let's say 10" for instance. The posts are 8 feet long, so the "leftover" length is (8'-0" - 10") = 7'-2". Measure the "leftover" 7'-2" from the offset marks you previously made on each post, and mark these at the top ends. Use a square to transfer this mark all around the posts so that you have a cut line wrapping around the post.

Using a circular saw, cut along this line on each post, then flip the posts to cut the opposite face from the first cut. Use a reciprocating saw to finish the cut, assuming that your circular saw doesn't cut all the way through with the first two passes.

Step 6: Mark Top Tenons, Cut Tenons, and Chamfer Edges

The tops of the posts need to be cut into a tenon to hold the secondary beams. To do so, measure down from the newly-cut top of the posts to the depth of the secondary beams, in this case 7-1/4" for the 2x8 boards. Make a mark and square it across the width of the post with a speed square. Transfer this mark all around the post.

Next, measure in from one face to the thickness of the secondary beam, 1-1/2" for these. Mark this for the full depth of the beam, which I did with a combination square, but which you can easily do by making two marks and connecting them with a straight edge. Do this for both opposing faces of the post to establish the cut lines for the tenon.

Using the circular saw, set it to cut the depth of the secondary beam (1-1/2"), and make a cross-cut to establish the shoulder of the tenon. Roll the post and make the same cut on the opposite face.

Reset the circular saw to its maximum cut depth and roll the post 90 degrees to begin cutting the cheeks of the tenon. You want to stop when the saw blade meets the shoulder cut that you previously established. Don't over-run the shoulder cut, or your joint will look quite bad. Make the other cheek cut on the same side of the post, then roll it to cut the cheeks on the opposite face. Finally, finish the cut with the reciprocating saw.

This next step is optional, but I highly recommend it. Put a 45-degree chamfer bit in a palm router, and use this to ease the edges of the post from bottom to top. Not only does this provide a pleasing look to the posts, but it also protects the corners from splintering off from an errant bump and also softens the corners should someone run into them.

Step 7: Plumb the Posts and Attach to Post Bases

Now to start making the pergola take shape!

We're going to start by raising and plumbing the posts. At one of the corners, place a post in the post base, but laying down on the ground. Pound in a wooden stake about 6 feet away from the post base next to the laid-down post, and another one 90 degrees around the post so that you can brace from both sides. Take two of the spare 2x4s, and attach each at each of these stakes with a single nail for now, and lay them down also.

Stand the post up and grab one of the braces you previously laid down, and bring the brace around into contact with the post. Using the 4-foot level, plumb the face of the post aligned with the brace. Once satisfied with the plumb-ness of the post, use a nail to tack the brace in place.

Grab the other brace, and repeat the steps above to plumb the post from the other direction. Double check that the post is still plumb in both directions, then go ahead and drive another couple nails into the brace at either end.

Now, take your drill with a drill bit slightly smaller than the HeadLOK screw, and pre-drill holes to match those in the post base. Drive in the HeadLOK screws into these holes. For these particular post bases, there are four holes total, with two on each side. At this point, your post should be secure top and bottom and shouldn't move when casually jostled.

If, like me, you're building this pergola close to a house, you may have to brace the adjacent post against the first one, as in the last three pictures.

Step 8: Cut the Secondary Beam Tails

Calling these "secondary" beams might seem a little odd since they go in first, but since they resist practically no bending load, I thought the term was fitting.

Bring over the 2x8x10ft secondary beams from the pile and set them on the sawhorses. Trace out a pleasing curve or other shape on the tail of the beam. I opted for a simple curve on mine, but feel free to be as creative as you please.

Using a jigsaw, cut out the tail of the beam. With the cutoff piece, trace the remaining tails of the beams, and proceed to cut them out too.

Step 9: Install the Secondary Beams

This is one step where having a clamp or two is helpful. Hoist one of the secondary beams up to the top of the posts and rest it in the notch cut previously. If you have a clamp, use it to hold the beam in place. If not, hopefully someone can hold it there for you, otherwise you might be rolling the dice with it possibly dropping on your head.

Using the drill, pre-drill three holes in a triangular pattern (like a play button ▶️) where the beam sits on the post. Then drive home three of the HeadLOK screws to fasten the beam to the post. Repeat this on the other end of the secondary beam.

Place the second secondary beam on the opposite side of the post, and repeat the steps above to fasten it. Then, at the other end of the pergola, install the remaining two secondary beams. If you braced one post back to the other, as I did, you can remove this at this point since the beams are providing the same function.

Step 10: Cut the Main Beams

The main beams are made from the 2x8x14ft boards. Bring these over to the saw horses, trace out, and cut the tails, same as you did with the secondary beams.

Next, roll all of the beams such that the bottom edges are facing upwards and clamp them together. We're going to measure, mark, and cut out the half-lap notches where the main beams overlap the secondary beams.

Measure the distance between the secondary beams at the top of the pergola, and also the distance between adjacent secondary beams where they attach to the posts. Mark these distances on the main beams, being sure to center everything on the length of the beam so that the overhang is the same on both ends. I would suggest adding a heavy 1/16" oversize on the thickness allowance for the secondary beams, just to allow the main beams to fit over them a little easier. Don't overdo this though, otherwise the fit will be too sloppy.

Set your circular saw depth to about 1-1/2" cutting depth and cut just inside the lines you marked, which form the walls of the half-lap notches. Then, use the circular saw to cut between these lines 5-7 times, effectively making the notch look like []_[]_[]_[]_[] when viewed from the side. This will make it easy to knock the waste out with a chisel, and use the chisel to clean up the bottom of the notches.

Pro Tip: if you have a router with a flush trim bit, you can use this to very quickly smooth the bottoms of the notches. I bought one half way through the project and so didn't use it here.

Step 11: Install Main Beams

Unclamp and hoist a main beam up to the top of the pergola, resting it on the secondary beams. Roll it over and slip the half-lap notches over the secondary beam, butting the main beam up against the posts. You may have to persuade it into position with a mallet or sledge.

Once you're satisfied with the location, toe-nail it in place onto the secondary beams. Since these beams won't take much loading besides the vertical dead load, there is no real need for more than one nail at each half-lap joint. If you're using a nail gun and the nail doesn't get set down enough, drive it home with a hammer and adjust the settings on your nail gun so the nail travels further.

Repeat the above steps for the remaining three main beams.

NOTE: At this point, it may be prudent to install the braces (Step 17), especially if you won't be able to finish the pergola in the near future. The braces will protect against the pergola from falling over in high winds, and also add a lot of stiffness to the structure when crawling around on top later. I opted to install the braces at the very end, which perhaps wasn't the smartest idea in hindsight.

Step 12: Cutting the Rafters

With the main beams in place, measure the distance between the main beams on one side of the pergola and check it against that measurement on the other side. If those two measurements are the same, great. If not, then you'll have to customize your half-lap cuts for each rafter, which is a pain.

The rafters are the 2x6x10ft pieces. Bring these out, trace a new end treatment, and cut them out on all rafters, like the beams before. For my situation, the back of the rafters was against the siding of the house, so I left these ends square and only cut the fronts. Your situation may vary.

As before with the main beams, measure out and mark the half-lap notches for where the rafters overlap the main beams. Set your circular saw at about 1" depth, cut, and chisel out the notches.

Step 13: Installing the Rafters

Mark out the rafter locations on the main beams. This is easily done by measuring the distance you want the rafters to spread over and divide by the number of rafters minus 1. For example, say the distance is 100 inches and you have 11 rafters. Your center-to-center spacing would be (100 inches) / (11 - 1) = 10 inches. Mark the locations on one of the beams at each end of the pergola so that you can line them up parallel from front to back.

Installation of the rafters is exactly the same as the main beams, just that there are more of them.

Step 14: Cutting the Purlins

For my purlins, I used 2x4x14ft boards. Again I traced a simple curve on the ends and cut them with a jigsaw. After this, I flipped them bottom-up, lined the boards up, and clamped them together. Most likely the boards will all have some slight bend to them, so you may have to fiddle with the boards to get the bottom edge relatively even across all the boards.

Marking the half-laps where the purlins fit over the rafters uses the spacing determined in the previous step. In the previous example, a 10" spacing was determined, and 11 rafters total were used. Since the number of rafters is odd, one of them should be in the exact center of the purlin. You can then measure 10" increments on either side for spacing out the purlins, and then mark out the thickness of the rafters to cut the notches.

For cut depth here, I would use about 3/4" on the circular saw. Given all of the lap joints, cutting and chiseling them will take a little while. This is where the flush trim router bit comes in real handy when smoothing the bottoms of the notches.

Step 15: Install Purlins

Similar to the before, determine the spacing of the purlins on the rafters. Mark this spacing on either side of the pergola. If you have two people, it's then a relatively simple matter to stretch a chalk like across the pergola and snap marks for each purlin on the tops of the rafters. If you're working by yourself, as I was, this is also possible, though much more time-consuming.

Install the purlins in the same manner as the rafters and main beams. I found that, in a few spots, I had to clamp the purlin to the rafter at the half-lap because one of the boards had a bend in it and they weren't making full contact.

Once all the purlins are installed, the top of the pergola is done!

Step 16: Cut, Glue, and Nail Braces Together

Ok, home stretch!

The braces for this pergola are simple double 2x6 pieces, glued and nailed together. Trace out and cut a fancy pattern in the braces if you so desire, or just leave them plain.

Mark a 45-degree cut at the end of one of the 2x6x8ft boards, and another one 4ft away from that. Make both cuts with the circular saw, then take the cut-off piece, lay it against the first board, and use it to trace the final 45-degree cut. Make this cut as well.

Squeeze out an exterior-rated glue (Titebond III, in my case) on one of the pieces and clamp the other piece to it. Nail the two boards together in a zig-zag pattern, with nails spaced about 6" apart.

Repeat for all braces.

Step 17: Install Braces

Since my pergola is asymmetric from front to back, the rear braces are installed a little differently from those in the front. Your situation may be different, so please adapt as necessary.

Clamp the brace to the post (if possible) and to the beam at the other end. Once satisfied with the location, pre-drill four holes at each attachment point, and drive in HeadLOK screws to fasten the brace to the post and the beam.

If your brace butts against the post (last two photos), then pre-drill angled holes in the brace and fasten that way.

Repeat until all braces are installed.

Step 18: Finished!

Congratulations! You've completed your pergola! Take a couple minutes to walk around it and admire your handiwork.

I hope you've enjoyed reading my Instructable, and more importantly, I hope I've given you enough detail that you can tackle this project yourself. If you have any questions, please feel free to ask them in the comments and I will help as much as I can.

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