Pergolas and shading — πέργκολες

The meltemi decides the design

Owners arrive with a picture of a pergola from a Mediterranean garden centre. It will not survive here, and the failure is not gradual — it is one night in July when the meltemi gets up and the whole thing leaves the terrace.

• Fabric must come off, or fold away. Any shade sail or canopy that cannot be furled or removed is a sail in the literal sense. The structures that survive are the ones whose fabric spends the windiest nights in a cupboard.
• Uplift, not downforce, is the design case. Wind over a terrace lifts. A structure held down by its own weight is a structure that has never met a gust here, and the fixings are the whole job.
• Section sizes are bigger than they look elsewhere. A slender frame that reads beautifully in a photograph is undersized here, and an installer who works on this island will say so.
• Exposure varies enormously. Imerovigli on the rim and a sheltered courtyard in Megalochori are different design problems on the same island. Nobody can specify this properly without seeing the site.

Fixing into what is actually there

The second problem is the substrate. Terraces here are rendered concrete, rubble stone, or excavated tuff, and each takes a fixing differently.

Expansion bolts rely on a strong, homogeneous material to grip against. Volcanic tuff is neither — it crumbles locally around the anchor under cyclic wind loading, so the bolt is tight on the day and loose after a season. The answer is resin anchoring into a cleaned hole, sized for the pull-out load rather than for the bolt diameter.

On a rendered rubble wall the anchor has to reach past the render into something structural, which means somebody has to find out what is behind it first. On a yposkafo, fixing into the vault at all is a question for an engineer rather than an installer, because the loads go somewhere.

What planning will allow

In the traditional settlements — and that is most of the ones people want to build a terrace in — the external appearance of a property is controlled. A pergola is external appearance.

• Size, height and projection are commonly limited, and a large fixed structure may need a permit where a removable one does not.
• Materials and colour are constrained. Timber and painted steel in muted colours generally pass; bright fabric and reflective aluminium frequently do not.
• Anything visible from the caldera path attracts more scrutiny than something in a rear courtyard.
• A structure that is judged permanent can affect the building's recorded footprint, which is a separate and more serious problem at sale.

The practical route is to establish what is allowed before choosing what you want, which is the reverse of how most people do it. Traditional settlement compliance covers the rules; building permits covers when you need one.

What this trade covers

• Timber and steel pergolas designed for local wind exposure.
• Bioclimatic and louvred systems, which close against wind and rain.
• Shade sails, including the anchor design that actually holds them.
• Retractable awnings with wind sensors — worth having, and worth testing.
• Reed and cane traditional shading, replaced on a cycle.
• Repairs and re-fixing after wind damage, which is a steady trade here every summer.
• Seasonal removal and refitting of fabric.