A sign can look perfect the day it goes up and look tired by the end of its first summer. In the Eastern Province a sign gets hit by four things at once: fierce sun, high temperatures, humid salty air near the coast, and fine dust blowing in on the wind. The right materials can take all four. The wrong ones fade, rust or go dark.

This is what we'd ask for, and what we'd avoid, when ordering an outdoor sign.

Metals: get the right grade of stainless

Stainless steel is a favourite for 3D letters because it looks expensive and doesn't need painting. Not all stainless is the same, though.

  • Grade 304 is fine indoors and away from the sea.
  • Grade 316 has molybdenum in it, which makes it much better at resisting salt. On the coast in Dammam, Khobar and Jubail, the salt in the air eats into 304 and leaves little brown pits. For any outdoor sign that gets sea air, ask for 316.

Aluminium is light and doesn't rust, which makes it great for letter sides, backs and fascia frames. Ask for a powder-coated finish. Plain paint goes chalky and fades much faster in strong sun.

Don't forget the small parts. A stainless sign hung on mild-steel brackets will still get rust streaks. The fixings should be at least as good as the sign.

Plastics: cast acrylic and polycarbonate

Acrylic is the usual material for the face of a lit sign, and there are two kinds:

  • Cast acrylic is more stable and usually resists going yellow in the sun.
  • Extruded acrylic is cheaper, but it's more likely to discolour and crack after years in the sun.

If the face needs to take knocks, say on a low sign that people walk past, polycarbonate is tougher. Outdoors it has to be a UV-stabilised grade.

Vinyl and printed faces

The graphics stuck onto signs and glass come in two main types:

  • Cast vinyl is thin, moulds well to shapes, and keeps its colour and size longer outside.
  • Calendered vinyl is cheaper and fine for short jobs, but it shrinks and fades sooner.

For printed faces, ask for UV-resistant inks with a protective laminate on top. Without it, reds and yellows are usually the first colours to wash out.

LEDs and power supplies

When a lit sign fails in summer, it's rarely the LEDs. It's usually the power supply. Drivers are rated for a maximum surrounding temperature, and a closed sign box in direct sun gets much hotter than the air outside it.

Ask whoever is quoting:

  • Are the LED modules sealed and rated IP65 or higher for outdoor use?
  • Is the power supply rated for high temperatures, and is it somewhere air can move around it?
  • Can someone reach the drivers to replace them without taking the whole sign down?

Dust and sealing

Fine dust gets into every gap. Inside a light box it settles on the LEDs and the back of the face and dims the whole sign. Good signs have sealed access panels and sealed letter backs, with small drain holes so condensation can get out.

A quick checklist

When you compare quotes, make sure the outdoor sign includes:

  1. Grade 316 stainless steel on coastal sites, or powder-coated aluminium.
  2. Cast acrylic or UV-stabilised polycarbonate faces.
  3. Cast vinyl or UV-laminated prints.
  4. Sealed LED modules rated for outdoors.
  5. Power supplies rated for high temperatures, somewhere ventilated and easy to reach.
  6. Stainless fixings and sealed joints.

Cheaper materials can bring the first price down, but they often cost you more later when the sign needs a new face or a rebuild. Not sure what a quote actually includes? Send it to us and we'll go through it line by line.