EN 988

EN 988, Zinc and zinc alloys – Specifications for rolled flat products for building, is the European Standard for architectural zinc, the material often called titanium-zinc. It is published by CEN through technical committee CEN/TC 209 (Zinc and zinc alloys). The edition in use is EN 988:1996; CEN completed a periodic review of it in December 2024.

Scope

The standard sets requirements for rolled flat products made from a zinc-copper-titanium alloy and supplied as strip, sheet or cut lengths for building. It covers:

• thicknesses from 0.6 to 1.0 mm (about 0.024 to 0.039 in)
• widths from 100 to 1,000 mm (about 4 to 39 in)

It does not cover formed or shaped products, or products processed other than by cutting to size.

Why the alloy matters

Unalloyed zinc is too brittle for roll-forming, folding and deep drawing. Small additions of copper and titanium improve strength, creep resistance and formability, which allows standing seam roofs, flat-lock panels, gutters and downpipes to be made from it. EN 988 sets limits for alloy composition, mechanical properties and dimensional tolerances so products from different mills behave consistently.

Use

Zinc roofing has a long history in continental Europe, especially France, Belgium, Germany and the Netherlands, and is used on roofs, façades and rainwater systems. Over time zinc forms a blue-grey patina of zinc carbonate that protects the metal. Pre-weathered and pigmented finishes are also produced so the patinated look is present from installation.

Installation considerations

Zinc must be detailed so that its underside is ventilated or otherwise protected, because moisture trapped against the back of the sheet can cause corrosion. Contact with copper run-off and some timbers should also be avoided. National rules such as the German ZVDH and French DTU documents give detailing requirements.

Related standards

European product standards for metal roofing sheet reference EN 988 for zinc. In North America, there is no widely used equivalent ASTM product standard, and European zinc is commonly supplied to EN 988.