Sun Shade / Shade Sail: Frequently Asked Questions

These are fabrics that are designed to help protect you from the harmful UV rays and intense heat of being directly exposed to the sun.
They are frequently suspended between buildings and/or posts with eye-catching designs that not only help water to run-off them but also to avoid trapping hot air beneath them.
They are usually highly tensioned and have curved edges to keep all the fabric taut to avoid the fatigue issues of them flapping in the wind.
There are now many regular sizes in both triangular and square shapes that can be purchased ready-made or companies that can offer a full installation service or simply supply a shade to the custom dimensions you may require.

Most are very effective at blocking the sun, usually having a shade factor between 85 – 100%, where 100% means that no visible light passes through (you cannot see through it).
However, that is not the full story. The shade factor is different to UV Block. The amount of dangerous suns rays that pass through the sail can actually be different to the shade factor and different manufacturer’s designs and material will offer different protection.
When selecting your sun shade you then need to decide on your preferred balance between these factors.
Eg
A shade offering 100% shade block that might make it dark underneath and not drain when it rains.
A light-colored shade that is aesthetically pleasing but is too bright to sit under etc
For further information the check out Planning for a Sun Shade- what you need to be thinking about
or more specifically the section Shade Factor

Like anything, this depends on the quality of the product bought and even more on the way it has been installed.
If installed correctly then good quality sun shades with appropriate fixings can stand winds up to around 75mph / 120Km/h
The installation of the shade is critical as considerations such as wind funneling, the strength of mounting points, if extensions have been used, the shape of the shade (flat, hypar etc) and the tension of installation, can all affect the ability of the shade to withstand higher wind strengths.
In all cases they should be taken down in extreme weather (snow, hurricane etc) as the damage that the shade can do, even if it doesn’t tear itself but simply flaps until it breaks a mounting point, can be devastating.
Check out Planning a Sun Shade or How to Install a Sun Shade for more information on the loads to be considered.

Yes and No! This depends on the manufacturer of the shade but the most common forms of ready-made shades are made from HDPE mesh and are not waterproof. The gaps in the mesh are small and in a gentle shower the run-off feature of the mesh, having being installed with a slope, may mean you do not get wet but in heavier downpours, water will come through the mesh like a sieve and run down both the outside and underside of the material.
There are some shades that are made to be impermeable so as to offer shelter in the rain and shade in the sun but these are more usually associated with commercial installations.

No.

It is true that lighter colors reflect more sunlight, which means the shade itself will not absorb the heat of the sun as quickly. This, in turn, means the area directly around the shade does not suffer as much from the radiated heat coming from the shade. This is not so important for a shade sail that is well ventilated but when the same shade cloth is used as part of a roller blind or against a window it can make a difference.

It is wrong, however, to assume that being under a darker shade will be hotter. Yes, the darker color will absorb more of the heat and light, rather than reflecting it, but the material is of such lightweight that it doesn’t really retain the heat, whereas something dense and solid, such as a flagstone does retain the heat and stay hot, even if it is a light color. The shade sail’s low thermal mass means that it cools easily just with the flow of air up through the mesh.

Lighter colors also have a lower shade factor (it is brighter underneath them) compared to darker colors of the same material. When light hits a lighter color the higher reflection causes the surface to appear brighter, with more glare, often making a darker color more suitable.

As with most things, shade sails come in a variety of different qualities and that is usually reflected in the price. The difference is mainly in the materials used to make the shade sail as the design of them is fairly standard.
Cheaper shade sails: 1~3 years
Brand Shade Sails: 5 ~ 12 years

The more expensive brand shade sails differentiate themselves not only with the features they provide but also with the warranty they offer. These will normally cover the shade as a whole (stitching, fittings etc) for between 1-2 years and then have a secondary warranty that covers the material for things like degradation, fading, UV protection etc for a period of 3-10 years.

In most cases the heaviness/thickness of the shade is a good indicator as to the quality and the longevity; the higher the GSM (grams per square meter) the better.

The single biggest factor that can reduce the life of your shade sail is poor installation. For further information check out Planning for a Sun Shade- what you need to be thinking about or How to Install and Tension a Sun Shade.

If you are looking to buy a ready-made shade sail to fit a particular area then having identified your strong mounting points you need to allow about 12″ / 30cm from each corner of the shade sail to the mounting point, for the tensioning device and fixings.
Eg. If you have two strong mounting points on the side of your house that are 10 feet apart then the maximum length for that edge of the sail should be 8 feet (10 feet – 12″ first corner- 12″ second corner).

Note: It is OK for the sail edge to be smaller than 8 feet and to then use an extension from the mounting point to the corner of the sail but if you buy a sail that is greater than 8 ft you may not be able to tension it correctly to get the best out of the sail.
For more information then do check out our Planning a Sun Shade – What you need to be thinking about. or more specifically Which Shade.

Most shade sails are made from HDPE – (High Density Polyethylene). These are monofilament threads that make an inherently mold and mildew resistant fabric. They are usually constructed into a knitted mesh which boast great dimensional stability, a high strength-to-weight ratio, and will not tear or fray if they’re cut or pierced. They can have different shade factor’s depending on the manufacturer and will drain when wet.

There are other types of material that do not let water through or that are made from a Vinyl thread rather than the HDPE but these tend to be more expensive and are found more frequently on commercial shades.

For more information check our Planning for a sun shade or more specifically Types of Material – What do they mean.

YES. Shade sails are made with special cloth but still come in regular rolls of material that are 118″ or 150″ (300cm – 380cm) wide. Shade sails that are larger than these dimensions are made by sewing them together.

Depending on the manufacturer they will also cut a hollow of about 7-12% out of the edges and then attach some edge reinforcement tape / webbing. This tape is also sewn on using regular sewing machines and it is possible to make your own shade sail as explained on Sailrite.com.

YES, it is possible, however, the loading on a post for a sun shade is different from those usually experienced by a fence post and as such the method that was used for installing the fence post may not be adequate to suit a sun shade.
Check out Attaching sun shade to a fence post.
Or read our complete article How to Install and Tension a Sun Shade for further suggestions.

Yes but…
As with everything to do with sun shades the mounting point strength is absolutely critical. As with fence posts, when the balcony, deck or dock was constructed the loading for a sun shade was not part of the design considerations and therefore the post dimensions and footing sizes may not be adequate to deal with these loads. As an example, it may be possible to very firmly attach a suitably sized shade post to an existing deck post but does that deck post have suitable footings and strength especially given the additional height of the shade post above the deck. It is therefore recommended that you get a professional to assess the requirements.

Yes, but how you attach it is very important as the loads involved can be much higher than the loads required to install it.
Check our suggested mounting points in our How to Install and Tension a Sun Shade article.

Yes, the bricks used to build structural walls can make great attachment points, as long as you use the correct fixing to suit the brick.
Check out mounting to bricks in our 
How to Install and Tension a Sun Shade article.
Note: Attaching to bricks that are part of a dividing/separating wall that is not load-bearing (ie it is cosmetic rather than a structural) is not recommended as they may not have the strength required at the height usually desired for a Sunshade.

No. It is strongly discouraged as these walls are primarily for appearance and are not designed to have the structural strength to have a sun shade pulling sideways. We would suggest that you install a post alongside the wall with suitable footings to support the shade. Check our suggested mounting points in our 
How to Install and Tension a Sun Shade article.
Check out How to install a Sun Shade Post for further information.

Horizontal shades may be the easiest to install and plan but they can cause you headaches later on. If you are planning to remove your shade during bad weather and to maintain it / keep it clean then a horizontal shade can be very convenient. However for shades that are more permanently installed, the benefits of not gathering debris, draining rain more quickly and not trapping hot air so readily make shade locations with built-in changes of height very popular. They can also look more appealing.
Recommendations for how much change of height to use are quite varied but the minimum suggested is ~30% of the distance between posts (~17 degrees) and the maximum is really up to your personal choice.
Check out Changes in Height in our 
How to Install and Tension a Sun Shade for further information.

Yes. It is rarely the case that you have suitably strong mounting points at exactly the correct position for all corners of the sail to get the location of the shade you require.
It is necessary to make the mounting point at least 12″ / 30cm further than the corner of the shade, to allow for the fixings and tensioning device but it is then possible to extend this distance by means of a chain, wire strop or even non-stretching rope. The length of the extension is theoretically as long as you want, however, in practice keeping it as short as is possible is preferred.
When you extend, you are making the whole installation more prone flapping in the wind and will therefore require greater tension and possibly stronger fixings. So, it is common to do, but avoid doing so if you can.
Check our How to Install and Tension a Sun Shade article.

No. This is really a factor of aesthetics.
It is possible to have posts that are vertical but they may need to be slightly larger / stronger than a post that is angled away from the center of the sun shade.
The problem is that of the posts bending / flexing or potentially even buckling when the loads are added to tension the shade correctly plus the additional loads from windy conditions.
To offset this the posts can be angled away from the centre of the shade, making them much less likely to bend.
The recommended angle for the post is between 5 and 10 degrees away from the center of the shade.
Check out ‘How to Measure Angle of lean on a post‘ or How to install a sun shade post.

The depth of the footing (the amount of the post that is underground, usually in concrete) depends on the loads that are going to be applied to the post and the height where they occur.
If you have a very long post (+20′ / +5m), even for a small sun shade, then the footing depth needed will be greater than for the same size sun shade at 7′ / 2m.
As a rough guide, it is suggested that the footing depth is 1/3 to 1/2 of the height above ground.
ie if the intended shade height is 10ft then you need a post that is 15ft long; 10ft above ground and 5ft in concrete
For further information on depths and diameter of the hole for a sun shade please check How to Install a Sun shade.

The loads on most sun shade posts can be much higher than those of fence posts so the footing sizes are usually larger, in most cases deeper.
For a shade that is 172sq ft / 16m² the footing required for each post is about:
Depth: 3′ 7″ / 1m
Diameter: 15 3/4″ / 400mm
Check out our Table with footing sizes and our recommendations for footing installation.