How to Build a Patio Sunshade using Triangular Fabric

Your backyard area doesn’t have to be all about soaking in the sun. It’s nice sometimes to relax in a shady spot, shielded from the harsh rays. But what if you don’t have any large tree in the backyard to make shade in any specific area? To solve this problem, I’ve anchored freestanding posts to concrete and attached a triangular patio sunshade fabric to the structure.

The west side of our house has a large concrete slab area that extends from the house to the neighbors’ fence. During the summer the afternoon sun reflects the heat from the concrete onto the house causing the bedrooms on that side of the house to be very hot. The concrete slap also gets hot and becomes practically unusable during the hot days. So adding a sunshade to that areas would reduce the heat in the summer and potentially be used for building other projects.

When thinking about how to attach the triangular sunshade sail canopy over the area, I didn’t want to attach it to the fence or the house. The triangular sunshade fabric is 20’x20’x20. If attached to the house, during the windy days the fabric will flap up and down and will constantly vibrate and jerk the attachment. This most likely may cause damage to the house.

Because of the large concrete slab, the only option I had was to anchor the posts into the concrete and use those posts to stretch the fabric. Concrete is very strong and could withstand a lot of pressure from the sunshade constant pulling and jerking.

For this project, I used three triangular sunshade pieces with only four posts that are anchored to the concrete. I’ve used different methods of attaching these fabric pieces to the post.

Disclosure: Some of the links on this page as well as links in “tools for this project” and “material list” sections are affiliate links.

Step 1 – Make Four Post for the Sunshade

If you have the proper equipment these posts could be easily made at home. But because I didn’t have a welding machine, I’ve asked a local sheet metal shop to make them for me. I wanted the posts to be 10 feet tall so I could adjust the elevation of the sunshade attachment.

The post consists of 2″ stainless steel pipe and an 8″x8″ flat sheet metal plate that’s 1/4″ thick. The metal plate has four 5/8″ holes drilled 1″ from the edge on all four corners. Then the 8″x8″ plate is welded to the 2″ pipe in the center. Since this post will be installed outdoors and exposed to weather, the top of the post has a welded end cap. This will prevent the water from filling up in the pipe when it rains. 

Step 2 – Drill Holes in the Concrete

First, determine the exact locations of the posts. If you’re installing only one triangular sunshade, you may need only three posts. 

Since I have 10 feet long posts, I decided to use 1/2″ x 4 1/2″ concrete expansion anchors. When you stretch and tighten the sunshade fabric, you’re putting a lot of pressure on the post. Also, during windy days, the fabric will flap causing the post to vibrate and jerk. With that in mind, four of these 1/2″ anchors per post will hold it firmly. 

When drilling the holes in the concrete, make sure you’re at least 4″ from the edge of slap. If the hole is closer to the edge, the concrete might crack or break off during drilling. 

To drill the holes in concrete, you need to use a rotary hammer drill that is made for Slotted Drive System (SDS) plus drill bits. The hammer drill vibrates up and down while drilling, making it easy to drill through concrete. You also need to use a 1/2″ concrete drill bit specifically designed for an SDS plus hammer drill. These hammer drills are not very expensive and could be found for a good price especially used. 

Drill your first hole in the concrete. Use a shop vacuum to suck out concrete dust out of the hole.

Step 3 – Hammer in Expansion Anchors into Concrete

Now take the anchor and hammer it into the hole so that the threaded part is about 1″ sticking out from the ground. Insert the post over the anchor and tighten the nut with your fingers. Then drill the second hole on the opposite side while the post is in place over the first anchor. Vacuum the dust and hammer in the second anchor into the hole and tighten the nut. Finish drilling the remaining holes and hammer the anchors in. 

Having the base plate in place on concrete while drilling helps the concrete hole to be perfectly aligned with the hole in the metal plate. If you don’t use the bottom plate as a guide for drilling holes, the anchors will be slightly off and you will not be able to insert the plate over the four anchors. Especially when you just start drilling, the vibration of the hammer drill will cause the bit to slightly shift and will not align with the base plate.  

Step 4 – Secure Post to the Concrete Anchors

Before tightening the anchor nuts, make sure the post is leveled vertically. If it is not leveled, unscrew the nut and pull out the post. The side that needs to be raised up, place one washer over the anchor on the concrete. Then place the plate and post back over the anchors keeping the washer under the bottom plate. This will level the base plate and the post. 

Now place a washer on each of the anchors and then tighten the nut. Repeat the process to install the remaining posts. 

Wedge anchors are two-piece concrete anchors that are assembled into one unit. The steel rod is threaded on one end and the opposite end starts out slightly smaller in diameter and tapers out to the full diameter of the rod. A clip is then permanently attached to this end of the rod. A wedge anchor is inserted into a hole in concrete until the threads are below the surface of the concrete. The nut and washer are placed on the threads and tightened until finger tight. Using a wrench, the nut is then turned, which pulls the anchor up to wedge the clip between the stud and the wall of the concrete. 

Step 5 – Attach a 2″ Split Ring Hanger to the Post

To attach the fabric to the post I used 2″ split ring hanger that is typically used for hanging pipes. This hanger has a 3/8″ thread in the center for a rod. Attach this 2″ split ring hanger to the pipe post at the desired elevation. Then screw in a 3/8″ eyebolt to the pipe hanger. Make sure the eyebolt is pointed in the direction where the fabric will be attached to.

Step 6 – Clip Sunshade Fabric to the Post with a Snap Link

For this project, I used 20x20x20 triangular sunshade fabric that I purchased on Amazon. There are many different sizes and shapes that you could find, but I think the triangular sunshades looks really nice. Triangle canopy sail shades block up to 95% of UV rays. They won’t fade, rot, mildew, or mold. Each edge has a stainless steel D-ring for easy installation. 

There are several different ways to attach the fabric to the post. The first and easiest is to just use a snap link. Insert the snap link into the D-ring on the fabric and then clip it to the eyebolt on the post. 

Having snap links on all four posts makes it easier to take the sunshade down during the winter or on windy days. 

Step 7 – Attach Sunshade to the Post with Cable

If the second post is too far away and the sunshade could not be attached with a snap link, you could use a rope or a cable.  

Instead of using a rope, my preferred choice was to use 1/8″ aircraft cable. It’s much thinner than a rope and the breaking point is much higher. Cable does not rust and would last a long time outdoors. 

To connect the fabric to the post using a cable, I used the same method of attachment as on the zipline. Check out the zipline project that I’ve built in our backyards. The only difference is the cable size of the zipline is thicker. 

Take a thimble for 1/8″ cable, and pry it slightly open with a screwdriver. Snap it on to the D-ring of the sunshade fabric. Then feed the cable thru the D-ring and around the thimble. Secure the cable with two cable clamps. Stretch the fabric and measure the remaining distance from the fabric to the post. Cut the cable with a grinder slightly longer to wrap around the second thimble. 

Attaching the second end of the cable to the post is a little bit challenging. You need to make sure the fabric is stretched at the same time you need to wrap the cable around the thimble and secure it with cable clamps. To make this process easier, pull the cable thru the snap link stretching the fabric. Then fold the cable around the snap link. When you release the cable, you will see where you made the fold. Place a thimble in that fold and secure it with two cable clamps. Then with the thimble in place stretch the cable and clip it onto the snap link.  Enjoy the shade!