Andrew Yeckel > Stories > Shade sail installation

Installing a shade sail

This project required some study and deliberation before proceeding. Our deck is exposed to full sunshine for much of the day in summertime. The surface often reaches temperatures too hot for bare feet, so I decided to install a shade sail.

The house provides some attachment points, but at least one post is needed to complete the job. To figure out where to set the post, and where to place hardware on the house, I cut this scale model from a shoe box.

This is Minnesota, where frost heave is a problem. To anchor a 9 foot tall post, I dug a hole 42 inches deep to get below the frost line. The hole is 12 inches across, big enough to hold that cardboard tube in the picture.

Before filling the hole with cement, I braced the post with stakes to ensure that it remained plumb.

It took 320 pounds of cement to fill the hole. This meant mixing four 80 pound bags, one at a time, in a wheel barrow and shoveling it in there. It might seem like overkill, but this is the minimum footing size allowed in the local building code for a structural post.

A shade sail can put a lot of force on a free standing post in windy conditions, so I placed a large screw anchor in the ground to attach a guy wire to the post.

The guy wire pulls in a direction opposite the force of the shade sail, which prevents the post from bending.

Obviously installing the post was a lot of work. Attaching hardware to the house was straightforward, even though one of the corners is fairly high up the wall and I dislike working on an extension ladder.

It is critical to place the attachments at the correct distances and angles to evenly tension the sail, which is needed to remove the wrinkles from the edges. Getting this right is more complicated when the corners are attached at different heights like I have done.

One of the attachments can be reached from the balcony and the other from a small step stool, making it easy to strike the sail when a storm approaches.

Besides shading the deck, the sail also keeps the wall cooler, reducing the load on our air conditioner. After successful testing, I installed a second sail, which required a second post. To avoid using any guy wires, I used a 6x6 post with a much larger footing.

The footing required eight 80 pound bags of concrete mixed by hand, twice as much as the smaller 4x4 footing. This time I used a plastic tub and hoe, which is easier than than wheelbarrow.

The second sail attaches to the house where I can reach it from the balcony.

Without the shades the deck is a foot searing hellscape on a hot summer day. With them it is paradise. The rooms adjacent to the deck also stay notably cooler.

Also, I added a nifty clothesline for energy efficient drying of laundry.