Select Flashing Materials

Lead is not compatible with ZINCALUME® steel or COLORBOND® steel. ZINCALUME® steel or COLORBOND® steel, in contact with or receiving run off water from lead is prone to corrosion.

Instead of lead, the recommended flashing materials that can be formed on-site are soft zinc or aluminium.

Other popular flashing materials are COLORBOND® steel or ZINCALUME® steel sheet formed to suit the application. While zinc-coated steel can be used with ZINCALUME® steel or COLORBOND® steel, its generally lesser life span makes it impractical in the long term.

When using COLORBOND® Stainless steel we recommend the use of stainless steel flashing products. Flashings made from zinc-coated, zinc/aluminium alloy-coated and COLORBOND® prepainted steel should not be used with COLORBOND® Stainless steel.

Roof penetration flashings are also available in a wide range of rubber and aluminium materials, and these are commonly used.

In the event of roof renewals where lead flashing already exists and its re-use is desirable, the ZINCALUME® steel or COLORBOND® steel should be insulated from the lead by a suitable barrier. This can be achieved by painting the underside of the lead. Plastic film can also be used to separate the surfaces, provided it is robust enough and will not tear, eg Polyethylene damp-course.

Painting the underside of lead flashings already existing on an old building well enough to ensure separation is not easy. Polyethylene damp-course placed between the lead and ZINCALUME® steel or COLORBOND® steel sheet is a better alternative.

Lead in the water run-off can be avoided by painting the top surface of the lead flashing. Applying two or three coats of water-based acrylic is suitable but any painting should be maintained so that it will not break down and expose any of the lead surface.

This information is intended as a guide only. For further information, please see "Technical Bulletin 8 - Flashing Materials for ZINCALUME® steel and COLORBOND® steel Sheet" on our Technical Bulletins page.