How to Build a Pergola (attached to a house)

I’ve been determined to make our backyard space more inviting. I also went down a slippery slope when deciding how to accomplish this task. Basically I went from needing a new patio umbrella canopy, to then needing a tilted umbrella (to block the setting sun), to wanting a retractable awning, to building a pergola. Makes sense.

So I spent hours looking at dreamy pergolas on Pinterest and Insta. I could get everything I wanted if I had a pergola – I thought! An inviting outdoor room, beautiful vines, hanging outdoor curtains to block the sun, lanterns and Edison lights for summer nights! I was sold! But…I also found out that these structures could cost thousands of dollars. You know I don’t compute “thousands” – but I can compute $400 – which is how much my pergola ended up costing!

Disclaimer: There is not a standard size for a pergola (attached to a house). Your dimensions will depend on the size of your space. Therefore you should adjust its dimensions accordingly. My pergola dimensions are 14 feet wide and 11 feet deep with 12 foot cross beams and 7.5 feet in height – therefore the lumber required meets those specs.

Materials
(2) 6″ x 6″ x 10′ pressure treated posts
(1) 2″ x 8″ x 14′ pressure treated lumber for the ledger board
(2) 2″ x 8″ x 14′ pressure treated lumber for the support beams
(10) 2″ x 8″ x 12′ pressure treated lumber for the cross beams
(2) 2″ x 4″ x 8′ lumber (used for keeping posts plumb while concrete sets)
(10) 2″ x 8″ Joint Hangers 
(100) #10 1-1/2 in. External Hex Flange Hex-Head Structural-Connector Screw
(10) Hurricane Ties
(4) ThruLOK 9-1/2″ Bolt 
(12) LedgerLOK 3-5/8″ Ledger Board Fastener
(8) Bags of Sakrete 80 lb. Concrete Mix 
Post Level
Shovel
Drill
Clamps
Miter Saw
Measuring Tape
Level

Installing the Support Posts
Before beginning the actual work, you will have to decide the anchoring system for your pergola support posts. I decided I wanted our support posts to be anchored in concrete. I started by removing the paver stones on our patio and dug (2) 18″ x 18″ x 30″ holes. The distance between the (2) holes was 12 feet on center. Once set in the ground, the 10′ support posts would actually become  7.5′ – which is the height of the pergola.

 

Next, place each post into center of the hole (mine was in the center but was set back closer to the paver wall). Use 4 bags of high-strength concrete mix per hole. Follow the directions on the bag for the proper mixing instructions. If available – I recommend mixing the concrete in a wheelbarrow plus it also helps with transporting the concrete to the holes.

Fill each hole with the concrete mix. Pour mix so it’s level with the bottom of the paver stones. This allows you to place the paver stones back once the concrete is dry.

Using a post level – adjust the posts until they are plumb in both directions. Screw a 2″ x 4″x 8′ board into each post and stake the board into the ground. This helps to keep the posts vertical in both directions while the concrete sets. Remove 2″ x 4″ boards once the posts are stable (usually 24 – 48 hours).

Pergola Rafter Tail Design
Pergolas usually have a distinct design on the ends of the cross and support beams. Some people also call these rafter tails. I thought about doing a curved design but quickly realized that I would have to be very accurate with a jig saw 14 times. 10 times for each cross beam (since the other side is attached to the house) and 4 times for both support beams. I measured 3″ up from the bottom of the 2″ x 8″ beam and 3″ over to make a right triangle. Then cut the design using a miter saw at 45 degrees.

Attaching the Support Beams
Next, you’ll need to attach the 2″ x 8″ x 14′ support beams to the 6″ x 6″ support posts. Since the distance between the 2 support posts is 12′ – you will have 12″ of “overhang” on each support post. Attach both support beams to the top of the support posts using heavy duty clamps. Make sure that the support beams are level in both directions. Use (2) 9-1/2 in. Hex-Head Replacement Specialty Bolts (with caps removed) per post to attach the support beams. These allow you drill the bolts directly through the (2) beams and 6″ post without the need to pre-drill a pilot hole. Attach the end caps to the bolts once they are in place.

Installing the Ledger Board to Your House
Next, attach a 2″ x 8″ x 14′ piece of lumber to the house. This is also known as the Ledger Board. Position the ledger board so it is aligned with support beams (including the same height). Attach the ledger board to your house with (12) 3- 5/8″ LedgerLOK deck ledger fasteners (assuming if this part of your house is wood).

Next,  attach your first and last joist hanger to the ledger board. These should start  roughly 12 inches in from the edges of the ledger board. This allows your first and last cross beam to lay on the outside of your support posts.  Also, make sure the bottom of the joist hangers are at the same height as the top of your support beam in order for the cross beams to be level. Attach joist hangers to the ledger board using #10 structural-connector screws. Attach the (8) remaining joist hangers. These should be equally spaced – roughly 16 inches on center.

Installing the Cross Beams
Install each of the (10) 2″ x 8″ x 12′ cross beams. Place the end with the rafter tail on the support beam and slide the flat end on the beam into a joist hanger. Measure the distance between each cross beam on the support beam to make sure they are the same distance apart as the corresponding joist hanger. Also confirm that each cross beam is level.

Once all the beams are level and spaced correctly – attach the cross beams to the joist hangers using the same #10 structural-connector screws. Then attach a hurricane tie to each of the (10) cross beams and secure it to the support beam using #10 structural-connector screws.

Then step back and say “Holy shit! I built a pergola!”

Note: Pressure treated wood needs time (a few months) to dry out before you apply any paint or stain. To test whether the surface is dry, pour a small amount of water on it. – if the water beads up immediately instead of being absorbed, you should wait a little bit longer.

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