Shade sail shapesDraw the seats before you draw the sail.
The best outline covers the people at the hour they use the yard. The fence is only one of the constraints.
Start with a four-corner sail for a broad rectangular sitting area, a triangle for a smaller wedge, and multiple panels for separate or awkwardly shaped zones. Then test the shade. The outline above your head and the shadow on the ground are different things.
Read the shape by what it leaves out
Triangle
Useful for a corner or a small zone with three suitable anchors. Its narrowing tips leave less central coverage than many people expect. Draw the chairs underneath before choosing it.
Four-corner hypar
A broad area with two diagonally opposite high corners and two low corners. The curved surface helps the sail hold its designed shape under tension.
Several sails or a multi-point sail
Useful around an L-shaped footprint or two activity areas. Compare the gaps, the shared supports and the access for future servicing.
Why the sides curve in
A sail does not fill a rectangle drawn between its fixings. The inward-curving edges and the space for corner hardware reduce the covered area. This is why ordering a sail from the patio's edge dimensions can leave the outer chairs exposed.
Tension, pattern and corner heights work together. A flat four-corner sheet will flap and sag; the twist is what keeps it tight. Kit-sail planning guides show the same alternating corners and the same need to leave room for the fittings. Exact dimensions belong to the selected design.
One 6 by 8 metre yard
Say the yard is 6 m wide and runs 8 m north from the house. A table sits on the paving near the back door; the lawn extends beyond it. The family uses the table from lunch into late afternoon. Those are the yard's dimensions; the sail ends up smaller.
Three choices to make on this plan
Protect the chairs, keep the route clear
Mark the table with chairs pulled out and the walk from the back door to the lawn. Place supports outside that route, subject to services and engineering.
Test one four-corner sail first
The sitting area is one broad zone. Test whether a single sail shades it before adding a second panel over lawn that may not need cover.
Check the afternoon edge
At the target hour, see which chairs lose shade. Moving or extending the cover towards the incoming sun may help. Check the result for your own date and site, because lowering one corner does not always fix it.
The two house connections in the drawing are only candidates. If the building cannot carry them, the layout needs independent supports. Likewise, the low corner near the house needs its runoff resolved away from the entrance. A neat plan still has to work in section.
The shadow keeps moving
Ask for a shade check at the hours that matter, with the actual orientation, season, heights and nearby obstructions. Try the Shade Designer to explore the layout, then have the fixing points and coverage confirmed on site. More than forty years of this, and the argument about shape usually settles the moment somebody marks the chairs on the paving.
How do I recognise the alternating corners?
Walk around the outline: high, low, high, low. The two corners next to any high corner are both low; the diagonally opposite corner is high. “High” and “low” are relative to each other, and the real heights come off the drawing. Leave changes to an existing sail's geometry to its installer.
Can a shade sail be round or curved?+
The edges already are. Every edge is cut with a concave scallop so the perimeter cable can carry the tension, and those curves stay once the sail is up and tight. A true circle is an umbrella or a framed canopy, which is a different structure with different supports underneath it.
What size sail do I need for my patio?+
Measure the area you want covered at the hour you actually sit there, with the chairs pulled out and marked on the paving. Add the room each corner fitting needs, then let the fabric size come back off that. If the yard is tight, a shade check at your own orientation and heights is worth doing before the size is settled.
How many posts will I need?+
Count the corners. Every extra corner means another post, unless something already on site is strong enough to take that corner: a wall, a properly checked fascia, an existing structure. That is the real price of a clever outline, and it is worth knowing before you fall for the shape.
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