Your Ultimate Guide to Shade Sails
 

Why Shade Sails?

Shade sails are rapidly rising in popularity for their range of benefits. They can cover large areas at a fraction of the time and cost as other canopy structures. They're especially effective in shading outdoor areas with greater sun exposure. Shade sails are great for playgrounds, pools, patios, seating areas, courtyards, and anywhere else a canopy is needed. Many fabricators, business owners, and homeowners prefer them for their streamlined, stylish look.

The Need for Shade

With the rise in average global temperatures and increase in skin cancer, the demand for shade is increasing. Many community playgrounds are now requiring shade structures to protect children from the sun. Homeowners need a cost-effective way to keep their pools from overheating. Backyard patio areas can be transformed into outdoor rooms with the addition of shade. All of these applications have one thing in common: they are large spaces that can all be protected with shade sails.

Five Steps
 

Here are your five basic steps in building a shade sail:
 

• Design - Fabricator works with customer to determine size, shape, coverage, and color.
• Certification - Fabricator engages engineer to determine loads and design attachment points with sufficient strength to hold the shade sail in place.
• Build Shade Sail - Fabricator builds the shade sail.
• Build Attachment Points - Fabricator or local contractor builds footings and/or installs attachment hardware.
• Install Shade Sail - Fabricator installs and tensions the shade sail.
  
   

With few exceptions, most conventional awning fabricators already have everything they need in their shop to build an industrial shade sail. A large open floor space for layout and a heavy-duty sewing machine are the basic tools needed for building a shade sail.

When it comes to installing the poles and attachment points, the fabricator should consider engaging a local contractor that has all of the necessary equipment to dig footings, install cement, etc.

Shade Sail Design Software

 

Due to the large sizes and odd shapes involved in most shade sails, many fabricators use a shade sail design software. Trivantage^® has teamed up with Meliar Design to create an interface between Awning Composer^® and MPanel Shade Designer that allows fabricators to visualize shade sails.

The Shade Designer software uses basic dimensions like length, width, and pole height to create a three-dimensional object. The object can then be exported and superimposed over a site picture in Awning Composer. You can choose from different fabric options, colors, and poles to aid in the final design decision.

Once the customer approves the rendering, the MPanel software can be used to calculate the compound curves for the shade sail. Some shops run these dimensions into a cutter and create kraft paper patterns that they tape to the floor to use during the layout process. Other shops just use a dimensions report from the MPanel software and mark a pattern on the floor with tape.

Cutting the fabric panels on an automated cutter is not very practical since the width of most shade sail fabrics exceeds the width of the average cutter. The fabric is also very slippery and because it is mesh, it does not lend itself to being held down by air vacuum systems on most cutters.

Determining Loads

 

All shade sail footings and attachment points must be designed by a certified engineer that has experience in calculating shade sail loads. Due to their large size, these sails can develop large point loads on each of the connection points.

When applying for a permit to install a shade sail, building inspectors will want to see the calculations that went into determining these loads and how the poles, footings, and connecting hardware will deal with these loads.

Engineers often use specialized software for these calculations. Stamped, engineered drawings for each shade sail job are the minimum that each fabricator should start with before building.

What to Consider When Designing

 

• Ideally, any one side of a shade sail should not be longer than 30–35 feet. Larger sails up to 70 feet are possible, but can be difficult to build and install as they require very large posts and footings.
• Long and narrow sails should be avoided. Ideally, the length of the longest side of a shade sail should not be more than twice the length of the shortest side. This is particularly true with triangle shade sails. The reason is that spreading the load along a narrow sail can be difficult.
• Triangles and other flat shade sails should slant sufficiently to prevent pooling rainwater. A slope of at least 1:6 is recommended. Larger triangles or flat sails require more of a slant to avoid sagging and facilitate shedding of rain.
• When installing square or rectangle shade sails, the strength may be increased by twisting the sail into a hyperbolic parabola which gives a three-dimensional stretch to the fabric. You can also achieve a third dimension by attaching one corner of the quadrilateral significantly higher than the other corners. This distribution of overall tension results in a stronger shade sail that lasts longer than two dimensional shade sails exposed to the same conditions.
• Shade sails are not intended to hold snow and should be taken down where snow is a possibility.
• To avoid chafing of the fabric, overlapping shade sails should have a minimum of 12 inches of distance between them. Otherwise, windy conditions may cause the sails to rub against each other and may damage the fabric over time.
• When fixing a shade sail to a roof or building, it is very important to ensure that the attachment point is structurally strong. Many buildings are not designed to take the stresses generated by shade sails.
• Poles are generally tipped outward, away from the center of the shade sail to provide a pleasing visual look, but they may also be installed vertically.

Building Your Shade Sail
 

There are many decisions that the fabricator must make when building a shade sail and most of these decisions revolve around how to reinforce the shade sail so it spreads out the loading forces. While there is no magic solution to this design problem, experience helps a great deal.

 

Here are some useful guidelines:

 

• Use a one-inch overlap seam for sewing panels together. Use a double-needle machine for sewing the overlap seam or sew it twice with a single-needle machine.
• Use the same fabric for reinforcement and orient it so it matches the bias of the underlying fabric to ensure that the reinforcement stretches uniformly with the underlying fabric.
• Pockets for holding the outer rope or cable should be built using the same fabric. Since these outer edges are usually curved, you need to cut the pocket to match the curve, sew it in with a 1/2-inch indent and then top-stitch it.
• Pockets are usually built from two layers of material. Sew one edge of the pocket to the top of the shade sail first. Then install corner reinforcement patches to the bottom of the shade sail. Then insert the outer rope or cable and close the pocket by sewing the other edge of the pocket to the bottom of the shade sail.
• Use three layers for reinforcement patches. Put the largest reinforcement patch down first and sew that into place. Then the second largest patch should be installed and sewn into place. Finally, the smallest patch is installed. This last patch will have to be sewn through four layers of material so make sure your sewing machine is up to the task.
• The edge of the patch that is closest to the center of the sail should have a curved edge that is a uniform curve calculated from the center of the attachment point.
• Samples of reinforcement patch sizes on past jobs:
  
   

• The fabric has a bias with the most stretch going down the roll and the least stretch across the roll. When building a triangular shade sail, the bias should be aligned so the least amount of stretch is along the longest side. When designing a hypar (four-sided) shape, then the bias should be aligned so the least amount of stretch is along the ridge of the shade sail.

• Use PTFE thread so it lasts as long as the fabric.
• Any exposed edges should be cut with a hot knife to seal the fabric.
• Some fabricators like to use webbing instead of cable or bolt ropes. The webbing does not stretch much and therefore, the shade sail must be pre-stretched before webbing is sewn on or wrinkles will form. This is not seen as a viable solution on larger shade sails as it can be a difficult task.

Building Support Poles
 

In all cases, the size of the support poles should be calculcated by an engineer.

However, there are some handy rules of thumb:
 

• Point load x length of pole will be roughly equal to footing load. Example: a 1,000-lb point load on a 10’ high pole will be equal to a 10,000-lb load at the foot of the pole.
• Shade sails usually require the installation of thick-walled steel poles. These steel posts are usually powder coated so they have a hard, long-lasting finish.
• Most shade sail posts are bolted to concrete footings that have bolts imbedded in the concrete. It is common for the top of a footing to be below ground level so that the nuts attaching the pole to the footing are hidden. If there are gussets on the base of the post, these will also be hidden below ground.
• A common way to make sure the post fits the footing is to build two wooden templates that will be used for the bolt pattern. One of these templates goes to the steel fabricator and the other to contractor building the footing. This ensures that the post will bolt up to the footing at installation time.
  
   

Common Shade Sail Design Layouts

 

There are multiple ways to rig a sail shade, depending on the look, effect, and space requirements. How you want to create your custom shade sail is up to you, your client, and an experienced engineer.

Some common shade sail configurations:

Shade Sail Fabric 101
 

While conventional awning fabrics like Sunbrella® acrylic can be used to build a shade sail, most shade sails are built using a specialized mesh material. These fabrics are specifically designed for building shade sails and have several advantages over conventional awning fabrics:

 

• Shade sail fabrics are mesh rather than solid fabrics, which allows water to drain through. They are often made with HDPE (High Density Polyethylene).
• Their stretch characteristics make them easier to work with and prevent wrinkles.
• They are stronger than conventional fabrics which make them ideal for handling the stresses incurred in shade sail structures.
• They come in widths up to 12.5 feet which reduces the number of panels needed for a shade sail.
• We recommend stitching with a PTFE thread, like GORE^® TENARA^® or Aruvo™.

A snapshot of the shade sail fabrics we carry:

 

• Commercial 95^® 340: great for mid-sized projects
• Polytex^®: features a “Raschel Knit”
• SolaMesh^®: tested in the world's toughest conditions
• Comtex^®: excellent fire rating
• Sunbrella^® Contour: legendary Sunbrella performance
• Commercial Heavy^® 430: great for large-scale jobs
• Architec 400^®: unique blend of fibers for maximum endurance
• Commercial FR 300^®: flame retardant and UV resistant

Shade Sail Hardware 101
 

While selecting the right fabric is key, the shade sail hardware is just as important. The fittings must be positioned correctly to withstand tension and severe weather. Since each part provides an important link, care should be taken when selecting and installing your shade sail hardware.

There are two choices of hardware for installing shade sails: galvanized or stainless steel. Most fabricators prefer to use stainless due to its long-lasting properties.

A couple notes on installing shade sail hardware:

 

• The outer ropes or cables are usually terminated onto D rings in each corner. It is common to use turnbuckles on all connection points which gives the maximum flexibility when tightening up the shade sail.
• A block and tackle is normally used during shade sail installation to take up the initial slack and to attach the last turnbuckle.

A quick breakdown of parts

Brackets and mounting plates
 

Used for: Mounting the shade sail to the support structure or ground
Types: Corner bracket, fascia bracket, deck post bracket, diamond pad eye, wall plate

Nuts and bolts
 

Used for: Linking or securing parts together; screwing into the support structure
Types: Eye nut, eye bolt, washer, lock nut, hex nut

Rings
 

Used for: Linking or securing parts together; connecting fabric edge with support structure
Types: Dee ring, dee ring thimble, triangle ring, triangle quick link

Thimbles
 

Used for: Underlining and supporting the wire rope threaded in the shade sail
Types: Thimble, round thimble, dee ring thimble

Turnbuckles
 

Used for: A link between the fabric and support structure
Types: Jaw/jaw, hook/hook, eye/eye

To minimize binding on turnbuckle threads, we recommend using an anti-seize product

Rope clamps
 

Used for: Clamping loose ends of wire rope
Types: SolaMesh™, Polyfab™ Pro

Shackles
 

Used for: Linking parts together; a link between the fabric and support structure
Types: Bow shackle, dee shackle, twisted dee shackle

Spring hooks
 

Used for: Linking parts together; a link between the fabric and support structure
Types: Spring hook, snap hook, quick link

Wire rope
 

Used for: Threading into edge of fabric for support and rigging
Types: Stainless steel

Final Note

We would like to thank all of the fabricators who contributed to this article for sharing information for the good of the industry. See additional resources below.

Happy shading!

References & Related Links

Our Shade Sail Fabrics

Our Shade Sail Hardware

Polyfab Pro Shade Sail Hardware Guide

SolaMesh Shade Sail Hardware Guide

Polyfab Shade Sail Edge Webbing

Thread and Bobbins

Awning Composer

MPanel Shade Designer

Disclaimer: The purpose of this guide is to give fabricators who are not familiar with building shade sails some background information, so they can decide if this is a market segment they want to expand into.

This guide should not be considered as the sole source of information on shade sails and should not be considered as advice or instructions on how to build shade sails. This guide is strictly informational and relays how some fabricators may build shade sails.

All shade sails footings and attachment points should be designed by a certified engineer that has experience in calculating shade sail loads.